From 5ab6e7e4b5303409b18e86b403d1393d9aed3bf2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Mon, 5 Jan 2026 02:12:08 +0100
Subject: [PATCH 1/6] feat: make 6.0.1 be the latest pinned version

---
 lua/neotest-java/default_config.lua | 30 ++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/lua/neotest-java/default_config.lua b/lua/neotest-java/default_config.lua
index 34b36d2f..855effd9 100644
--- a/lua/neotest-java/default_config.lua
+++ b/lua/neotest-java/default_config.lua
@@ -1,8 +1,23 @@
 local Path = require("neotest-java.model.path")
 
-local DEFAULT_VERSION = "1.10.1"
-local JUNIT_JAR_FILE_NAME = "junit-platform-console-standalone-" .. DEFAULT_VERSION .. ".jar"
-local DEFAULT_JUNIT_JAR_PATH = Path(vim.fn.stdpath("data")):append("neotest-java"):append(JUNIT_JAR_FILE_NAME)
+local JUNIT_JAR_FILE_NAME = function(version)
+	return "junit-platform-console-standalone-" .. version .. ".jar"
+end
+local DEFAULT_JUNIT_JAR_PATH = function(version)
+	return Path(vim.fn.stdpath("data")):append("neotest-java"):append(JUNIT_JAR_FILE_NAME(version))
+end
+
+local SUPPORTED_VERSIONS = {
+	{
+		version = "6.0.1",
+		sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",
+	},
+	{
+		version = "1.10.1",
+		sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
+	},
+}
+local LATEST_PINNED_VERSION = SUPPORTED_VERSIONS[1]
 
 --- @class neotest-java.JunitVersion
 --- @field version string
@@ -18,14 +33,11 @@ local DEFAULT_JUNIT_JAR_PATH = Path(vim.fn.stdpath("data")):append("neotest-java
 
 ---@type neotest-java.ConfigOpts
 local default_config = {
-	default_junit_jar_filepath = DEFAULT_JUNIT_JAR_PATH,
-	junit_jar = DEFAULT_JUNIT_JAR_PATH,
+	default_junit_jar_filepath = DEFAULT_JUNIT_JAR_PATH(LATEST_PINNED_VERSION.version),
+	junit_jar = DEFAULT_JUNIT_JAR_PATH(LATEST_PINNED_VERSION.version),
+	default_junit_jar_version = LATEST_PINNED_VERSION,
 	jvm_args = {},
 	incremental_build = true,
-	default_junit_jar_version = {
-		version = DEFAULT_VERSION,
-		sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
-	},
 	test_classname_patterns = {
 		"^.*Tests?$",
 		"^.*IT$",

From 8de91a3ca0d1274b67bf74522ed519ca0705b5e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Tue, 20 Jan 2026 22:56:26 +0100
Subject: [PATCH 2/6] feat: support junit jar updates

---
 README.md                                     |   1 +
 lua/neotest-java/context_holder.lua           |   2 +
 lua/neotest-java/default_config.lua           |  11 +
 lua/neotest-java/init.lua                     |  61 +++-
 lua/neotest-java/install.lua                  | 184 +++++++---
 .../util/junit_version_detector.lua           | 106 ++++++
 tests/unit/init_spec.lua                      |  27 ++
 tests/unit/install_spec.lua                   | 323 ++++++++++++++++++
 tests/unit/junit_version_detector_spec.lua    | 149 ++++++++
 9 files changed, 809 insertions(+), 55 deletions(-)
 create mode 100644 lua/neotest-java/util/junit_version_detector.lua
 create mode 100644 tests/unit/install_spec.lua
 create mode 100644 tests/unit/junit_version_detector_spec.lua

diff --git a/README.md b/README.md
index 18dcdc4b..3fd56074 100644
--- a/README.md
+++ b/README.md
@@ -84,6 +84,7 @@
 | `junit_jar`         | `string?`   | `stdpath("data") .. /nvim/neotest-java/junit-platform-console-standalone-[version].jar`        | Path to the JUnit Platform Console standalone JAR.      |
 | `jvm_args`          | `string[]`  | `{}`                                                                                            | Additional JVM arguments passed when running tests.     |
 | `incremental_build` | `boolean`   | `true`                                                                                          | Enable incremental compilation before running tests.   |
+| `disable_update_notifications` | `boolean`   | `false`                                                                                          | Disable notifications about available JUnit jar updates. |
 | `test_classname_patterns` | `string[]`  | `{"^.*Tests?$", "^.*IT$", "^.*Spec$"}` | Regular expressions used to include only classes whose names match these patterns. Classes not matching any pattern will be ignored. |
 
 ## :octocat: Contributing
diff --git a/lua/neotest-java/context_holder.lua b/lua/neotest-java/context_holder.lua
index c0986a22..cc95be01 100644
--- a/lua/neotest-java/context_holder.lua
+++ b/lua/neotest-java/context_holder.lua
@@ -2,4 +2,6 @@
 return {
 	--- @type neotest-java.Adapter | nil
 	adapter = nil,
+	--- @type boolean
+	update_notification_shown = false,
 }
diff --git a/lua/neotest-java/default_config.lua b/lua/neotest-java/default_config.lua
index 855effd9..1b8eb3b5 100644
--- a/lua/neotest-java/default_config.lua
+++ b/lua/neotest-java/default_config.lua
@@ -19,6 +19,12 @@ local SUPPORTED_VERSIONS = {
 }
 local LATEST_PINNED_VERSION = SUPPORTED_VERSIONS[1]
 
+--- Get supported JUnit versions
+--- @return table[]
+local function get_supported_versions()
+	return SUPPORTED_VERSIONS
+end
+
 --- @class neotest-java.JunitVersion
 --- @field version string
 --- @field sha256 string
@@ -30,6 +36,7 @@ local LATEST_PINNED_VERSION = SUPPORTED_VERSIONS[1]
 ---@field incremental_build boolean
 ---@field default_junit_jar_version neotest-java.JunitVersion
 ---@field test_classname_patterns string[] | nil
+---@field disable_update_notifications boolean | nil
 
 ---@type neotest-java.ConfigOpts
 local default_config = {
@@ -38,6 +45,7 @@ local default_config = {
 	default_junit_jar_version = LATEST_PINNED_VERSION,
 	jvm_args = {},
 	incremental_build = true,
+	disable_update_notifications = false,
 	test_classname_patterns = {
 		"^.*Tests?$",
 		"^.*IT$",
@@ -45,4 +53,7 @@ local default_config = {
 	},
 }
 
+-- Export getter function for supported versions
+default_config.get_supported_versions = get_supported_versions
+
 return default_config
diff --git a/lua/neotest-java/init.lua b/lua/neotest-java/init.lua
index 80c4e181..28d64553 100644
--- a/lua/neotest-java/init.lua
+++ b/lua/neotest-java/init.lua
@@ -11,8 +11,10 @@ local ch = require("neotest-java.context_holder")
 local Path = require("neotest-java.model.path")
 local nio = require("nio")
 local logger = require("neotest-java.logger")
-local install = require("neotest-java.install")
 local Binaries = require("neotest-java.command.binaries")
+local version_detector = require("neotest-java.util.junit_version_detector")
+local lib = require("neotest.lib")
+local exists = require("neotest.lib.file").exists
 
 local DEFAULT_CONFIG = require("neotest-java.default_config")
 
@@ -58,7 +60,7 @@ end
 --- @param deps? neotest-java.Dependencies
 --- @return neotest-java.Adapter
 local function NeotestJavaAdapter(config, deps)
-	config = config or {}
+	config = vim.tbl_extend("force", DEFAULT_CONFIG, config or {})
 	deps = deps or {}
 	local _root_finder = deps and deps.root_finder or root_finder
 
@@ -69,6 +71,27 @@ local function NeotestJavaAdapter(config, deps)
 	-- create data directory if it doesn't exist
 	mkdir(Path(vim.fn.stdpath("data")):append("neotest-java"))
 
+	-- Check for JUnit jar updates (only if user hasn't disabled notifications and not already shown)
+	if not config.disable_update_notifications and not ch.update_notification_shown then
+		local existing_version, _ = version_detector.detect_existing_version()
+		if existing_version then
+			local has_update, latest_version = version_detector.check_for_update(existing_version)
+			if has_update and latest_version then
+				-- Mark notification as shown to avoid duplicates
+				ch.update_notification_shown = true
+				-- Show notification about available update
+				lib.notify(
+					string.format(
+						"JUnit jar update available: %s → %s. Run :NeotestJava setup to upgrade. (Disable: set disable_update_notifications = true in config)",
+						existing_version.version,
+						latest_version.version
+					),
+					"info"
+				)
+			end
+		end
+	end
+
 	local cwd = vim.loop.cwd()
 
 	--- @type neotest-java.Path|nil
@@ -118,7 +141,37 @@ local function NeotestJavaAdapter(config, deps)
 	return setmetatable({
 
 		install = function()
-			install(config)
+			local Installer = require("neotest-java.install")
+			local installer = Installer({
+				exists = exists,
+				checksum = function(path)
+					local f = assert(io.open(path:to_string(), "rb"))
+					local data = f:read("*a")
+					f:close()
+					return vim.fn.sha256(data)
+				end,
+				download = function(url, output)
+					local out = vim.system({
+						"curl",
+						"--output",
+						output,
+						url,
+						"--create-dirs",
+					}):wait(10000)
+					return out
+				end,
+				delete_file = vim.fn.delete,
+				ask_user_consent = function(msg, chs, cb)
+					vim.ui.select(chs, {
+						prompt = msg,
+					}, function(choice)
+						cb(choice)
+					end)
+				end,
+				notify = lib.notify,
+				detect_existing_version = version_detector.detect_existing_version,
+			})
+			installer.install(config)
 		end,
 		config = config,
 		name = "neotest-java",
@@ -141,7 +194,7 @@ local function NeotestJavaAdapter(config, deps)
 		end,
 	}, {
 		__call = function(_, opts, user_deps)
-			local user_opts = vim.tbl_extend("force", config, opts or {})
+			local user_opts = vim.tbl_extend("force", DEFAULT_CONFIG, opts or {})
 
 			if type(user_opts.junit_jar) == "string" then
 				user_opts.junit_jar = Path(user_opts.junit_jar)
diff --git a/lua/neotest-java/install.lua b/lua/neotest-java/install.lua
index a1535b43..25455d45 100644
--- a/lua/neotest-java/install.lua
+++ b/lua/neotest-java/install.lua
@@ -1,62 +1,144 @@
-local exists = require("neotest.lib.file").exists
-local lib = require("neotest.lib")
 local logger = require("neotest-java.logger")
+local version_detector = require("neotest-java.util.junit_version_detector")
+local Path = require("neotest-java.model.path")
 
---- @param file_path neotest-java.Path
---- @return string hash
-local checksum = function(file_path)
-	local f = assert(io.open(file_path:to_string(), "rb"))
-	local data = f:read("*a")
-	f:close()
-	local hash = vim.fn.sha256(data)
-	return hash
-end
+---@class neotest-java.InstallDeps
+---@field exists fun(filepath: string): boolean
+---@field checksum fun(file_path: neotest-java.Path): string
+---@field download fun(url: string, output: string): { code: number, stderr: string }
+---@field delete_file fun(filepath: string): void
+---@field ask_user_consent fun(message: string, choices: string[], callback: fun(choice: string | nil)): void
+---@field notify fun(message: string, level?: string): void
+---@field detect_existing_version fun(deps?: neotest-java.JunitVersionDetectorDeps): neotest-java.JunitVersion | nil, neotest-java.Path | nil
 
---- @param config neotest-java.ConfigOpts
-local install = function(config)
-	local filepath = config.junit_jar:to_string()
+---@class neotest-java.Installer
+---@field install fun(config: neotest-java.ConfigOpts): void
 
-	if exists(filepath) then
-		lib.notify("Already setup!")
-		return
-	end
-	local default_junit_jar_filepath = config.default_junit_jar_filepath:to_string()
-
-	local out = vim.system({
-		"curl",
-		"--output",
-		default_junit_jar_filepath,
-		("https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console-standalone/%s/junit-platform-console-standalone-%s.jar"):format(
-			config.default_junit_jar_version.version,
-			config.default_junit_jar_version.version
-		),
-		"--create-dirs",
-	}):wait(10000)
-
-	if out.code ~= 0 then
-		lib.notify(string.format("Error while downloading: \n %s", out.stderr), "error")
-		logger.error(out.stderr)
-		return
-	end
+--- @param deps neotest-java.InstallDeps
+--- @return neotest-java.Installer
+local Installer = function(deps)
+	--- @type neotest-java.InstallDeps
+	local exists_fn = deps.exists
+	local checksum_fn = deps.checksum
+	local delete_file_fn = deps.delete_file
+	local notify_fn = deps.notify
+	local detect_existing_version_fn = deps.detect_existing_version
+	local download_fn = deps.download
+	local ask_user_consent_fn = deps.ask_user_consent
+
+	--- Download JUnit jar for a specific version
+	--- @param version_info neotest-java.JunitVersion
+	--- @param target_filepath string
+	--- @return boolean success
+	local function download_junit_jar(version_info, target_filepath)
+		local url = ("https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console-standalone/%s/junit-platform-console-standalone-%s.jar"):format(
+			version_info.version,
+			version_info.version
+		)
+
+		local out = download_fn(url, target_filepath)
+
+		if out.code ~= 0 then
+			notify_fn(string.format("Error while downloading: \n %s", out.stderr), "error")
+			logger.error(out.stderr)
+			return false
+		end
+
+		local sha = checksum_fn(Path(target_filepath))
+		local expected_sha = version_info.sha256
+		if sha ~= expected_sha then
+			local message = ([[
+				Checksum verification failed!
+				Expected: %s
+				Got:      %s
 
-	local sha = checksum(config.default_junit_jar_filepath)
-	local expected_sha = config.default_junit_jar_version.sha256
-	if sha ~= expected_sha then
-		local message = ([[
-			Checksum verification failed!
-			Expected: %s
-			Got:      %s
+				Removed the file at %s.
+			]]):format(expected_sha, sha, target_filepath)
 
-			Removed the file at %s.
-		]]):format(expected_sha, sha, default_junit_jar_filepath)
+			delete_file_fn(target_filepath)
 
-		vim.fn.delete(default_junit_jar_filepath)
+			notify_fn(message, "error")
+			logger.error(message)
+			return false
+		end
 
-		lib.notify(message, "error")
-		logger.error(message)
-		return
+		return true
 	end
-	lib.notify("Downloaded Junit Standalone successfully at: \n" .. default_junit_jar_filepath)
+
+	return {
+		--- @param config neotest-java.ConfigOpts
+		install = function(config)
+			local filepath = config.junit_jar:to_string()
+			local default_junit_jar_filepath = config.default_junit_jar_filepath:to_string()
+
+			-- Check if already installed with latest version
+			if exists_fn(filepath) then
+				-- Verify it's the correct version by checksum
+				local current_sha = checksum_fn(Path(filepath))
+				if current_sha == config.default_junit_jar_version.sha256 then
+					notify_fn("JUnit jar is already set up with the latest version!")
+					return
+				end
+			end
+
+			-- Detect existing version
+			local existing_version, existing_filepath = detect_existing_version_fn()
+			local has_update, latest_version = false, nil
+
+			if existing_version then
+				has_update, latest_version = version_detector.check_for_update(existing_version)
+			end
+
+			-- If there's an existing version and it's not the latest, ask for upgrade
+			if existing_version and has_update and latest_version then
+				local message = string.format(
+					"JUnit jar version %s is installed. A newer version %s is available. Would you like to upgrade?",
+					existing_version.version,
+					latest_version.version
+				)
+				ask_user_consent_fn(message, { "Yes, upgrade", "No, keep current version" }, function(choice)
+					if choice == "Yes, upgrade" then
+						-- Remove old version
+						if existing_filepath and exists_fn(existing_filepath:to_string()) then
+							delete_file_fn(existing_filepath:to_string())
+							logger.info("Removed old JUnit jar: " .. existing_filepath:to_string())
+						end
+
+						-- Download new version
+						if download_junit_jar(latest_version, default_junit_jar_filepath) then
+							notify_fn(
+								string.format(
+									"Upgraded JUnit jar from %s to %s successfully at: \n%s",
+									existing_version.version,
+									latest_version.version,
+									default_junit_jar_filepath
+								)
+							)
+						end
+					else
+						notify_fn("Keeping current JUnit jar version " .. existing_version.version)
+					end
+				end)
+				return
+			end
+
+			-- If no existing version or user wants fresh install, download latest
+			if not existing_version or not exists_fn(filepath) then
+				local message = "JUnit Platform Console Standalone jar is required. Would you like to download it now?"
+				ask_user_consent_fn(message, { "Yes, download", "No, cancel" }, function(choice)
+					if choice == "Yes, download" then
+						if download_junit_jar(config.default_junit_jar_version, default_junit_jar_filepath) then
+							notify_fn("Downloaded JUnit Standalone successfully at: \n" .. default_junit_jar_filepath)
+						end
+					else
+						notify_fn("Setup cancelled. You can run :NeotestJava setup later to download the JUnit jar.")
+					end
+				end)
+			else
+				notify_fn("JUnit jar is already set up!")
+			end
+		end,
+	}
 end
 
-return install
+return Installer
diff --git a/lua/neotest-java/util/junit_version_detector.lua b/lua/neotest-java/util/junit_version_detector.lua
new file mode 100644
index 00000000..d374fb10
--- /dev/null
+++ b/lua/neotest-java/util/junit_version_detector.lua
@@ -0,0 +1,106 @@
+local Path = require("neotest-java.model.path")
+local exists = require("neotest.lib.file").exists
+
+local DEFAULT_CONFIG = require("neotest-java.default_config")
+
+--- @param file_path neotest-java.Path
+--- @param file_reader? fun(path: string): string
+--- @return string hash
+local function checksum(file_path, file_reader)
+	file_reader = file_reader
+		or function(path)
+			local f = assert(io.open(path, "rb"))
+			local data = f:read("*a")
+			f:close()
+			return data
+		end
+	local data = file_reader(file_path:to_string())
+	local hash = vim.fn.sha256(data)
+	return hash
+end
+
+--- Get supported versions from default_config
+--- @return table[]
+local function get_supported_versions()
+	return DEFAULT_CONFIG.get_supported_versions()
+end
+
+---@class neotest-java.JunitVersionDetectorDeps
+---@field exists? fun(filepath: neotest-java.Path): boolean
+---@field checksum? fun(file_path: neotest-java.Path): string
+---@field scan? fun(dir: neotest-java.Path, opts: { search_patterns: string[] }): neotest-java.Path[]
+---@field stdpath_data? fun(): string
+
+--- Detect which version of JUnit jar exists in the data directory
+--- @param deps? neotest-java.JunitVersionDetectorDeps
+--- @return neotest-java.JunitVersion | nil, neotest-java.Path | nil
+-- Returns: version_info, filepath
+local function detect_existing_version(deps)
+	deps = deps or {}
+	-- Create a wrapper for exists that accepts Path instead of string
+	local exists_fn = deps.exists or function(path)
+		return exists(path:to_string())
+	end
+	local checksum_fn = deps.checksum or function(path)
+		return checksum(path)
+	end
+	local scan_fn = deps.scan or require("neotest-java.util.dir_scan")
+	local stdpath_data_fn = deps.stdpath_data or vim.fn.stdpath
+
+	local supported_versions = get_supported_versions()
+	local data_dir = Path(stdpath_data_fn("data")):append("neotest-java")
+
+	-- First, try to detect by filename
+	for _, version_info in ipairs(supported_versions) do
+		local jar_path = data_dir:append("junit-platform-console-standalone-" .. version_info.version .. ".jar")
+		if exists_fn(jar_path) then
+			-- Verify by checksum to be sure
+			local file_sha = checksum_fn(jar_path)
+			if file_sha == version_info.sha256 then
+				return version_info, jar_path
+			end
+		end
+	end
+
+	-- If not found by filename, try to detect by checksum
+	-- This handles cases where the file might have a different name
+	local ok, jar_files = pcall(function()
+		return scan_fn(data_dir, { search_patterns = { "junit-platform-console-standalone-.*%.jar" } })
+	end)
+
+	if ok and jar_files then
+		for _, jar_file in ipairs(jar_files) do
+			-- jar_file is a Path object
+			local file_sha = checksum_fn(jar_file)
+			for _, version_info in ipairs(supported_versions) do
+				if file_sha == version_info.sha256 then
+					return version_info, jar_file
+				end
+			end
+		end
+	end
+
+	return nil, nil
+end
+
+--- Check if there's a newer version available than the one currently installed
+--- @param current_version neotest-java.JunitVersion
+--- @return boolean, neotest-java.JunitVersion | nil
+-- Returns: has_update, latest_version
+local function check_for_update(current_version)
+	local supported_versions = get_supported_versions()
+	local latest_version = supported_versions[1] -- First is always latest
+
+	if current_version.version ~= latest_version.version then
+		return true, latest_version
+	end
+
+	return false, nil
+end
+
+return {
+	detect_existing_version = detect_existing_version,
+	check_for_update = check_for_update,
+	get_supported_versions = get_supported_versions,
+	_checksum = checksum, -- Exposed for testing
+}
diff --git a/tests/unit/init_spec.lua b/tests/unit/init_spec.lua
index 868df09d..0fe06651 100644
--- a/tests/unit/init_spec.lua
+++ b/tests/unit/init_spec.lua
@@ -25,4 +25,31 @@ describe("NeotestJava plugin", function()
 		})
 		eq(nil, adapter.root("some_dir"))
 	end)
+
+	it("should respect disable_update_notifications config option", function()
+		-- Test that the config option is properly merged
+		local adapter_with_notifications = require("neotest-java")({
+			disable_update_notifications = false,
+		}, {
+			root_finder = {
+				find_root = function()
+					return nil
+				end,
+			},
+		})
+
+		local adapter_without_notifications = require("neotest-java")({
+			disable_update_notifications = true,
+		}, {
+			root_finder = {
+				find_root = function()
+					return nil
+				end,
+			},
+		})
+
+		-- Both should have the config set correctly
+		eq(false, adapter_with_notifications.config.disable_update_notifications)
+		eq(true, adapter_without_notifications.config.disable_update_notifications)
+	end)
 end)
diff --git a/tests/unit/install_spec.lua b/tests/unit/install_spec.lua
new file mode 100644
index 00000000..35524369
--- /dev/null
+++ b/tests/unit/install_spec.lua
@@ -0,0 +1,323 @@
+local Installer = require("neotest-java.install")
+local Path = require("neotest-java.model.path")
+local eq = require("tests.assertions").eq
+
+describe("Installer", function()
+	local version_6_0_1 = {
+		version = "6.0.1",
+		sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",
+	}
+	local version_1_10_1 = {
+		version = "1.10.1",
+		sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
+	}
+
+	local default_config = {
+		junit_jar = Path("/data/junit-6.0.1.jar"),
+		default_junit_jar_filepath = Path("/data/junit-6.0.1.jar"),
+		default_junit_jar_version = version_6_0_1,
+	}
+
+	it("should notify when already set up with latest version", function()
+		local notifications = {}
+		local exists_fn = function(filepath)
+			return filepath == "/data/junit-6.0.1.jar"
+		end
+
+		local checksum_fn = function(_file_path)
+			return version_6_0_1.sha256
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return nil, nil
+			end,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		eq(1, #notifications)
+		eq("JUnit jar is already set up with the latest version!", notifications[1].message)
+	end)
+
+	it("should ask for upgrade when older version is detected", function()
+		local notifications = {}
+		local user_choices = {}
+		local downloads = {}
+
+		local exists_fn = function(filepath)
+			-- Return true for old version, false for new version (not downloaded yet)
+			return filepath == "/data/junit-1.10.1.jar"
+		end
+
+		local checksum_fn = function(file_path)
+			local path_str = file_path:to_string()
+			-- Return checksum based on file path
+			if path_str:match("1%.10%.1") then
+				return version_1_10_1.sha256
+			elseif path_str:match("6%.0%.1") then
+				return version_6_0_1.sha256
+			end
+			return version_6_0_1.sha256
+		end
+
+		local ask_user_consent_fn = function(message, choices, callback)
+			table.insert(user_choices, { message = message, choices = choices })
+			-- Simulate user choosing "Yes, upgrade"
+			callback("Yes, upgrade")
+		end
+
+		local download_fn = function(url, output)
+			table.insert(downloads, { url = url, output = output })
+			return { code = 0, stderr = "" }
+		end
+
+		local delete_file_fn = function(_filepath)
+			-- Mock delete
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return version_1_10_1, Path("/data/junit-1.10.1.jar")
+			end,
+			ask_user_consent = ask_user_consent_fn,
+			download = download_fn,
+			delete_file = delete_file_fn,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		-- Should have asked for upgrade
+		eq(1, #user_choices)
+		assert(user_choices[1].message:match("upgrade"), "Should ask about upgrade")
+
+		-- Should have downloaded new version
+		eq(1, #downloads)
+		assert(downloads[1].url:match("6%.0%.1"), "Should download version 6.0.1")
+
+		-- Should have notified about upgrade
+		local upgrade_notification = false
+		for _, notif in ipairs(notifications) do
+			if notif.message:match("Upgraded") then
+				upgrade_notification = true
+				break
+			end
+		end
+		assert(upgrade_notification, "Should notify about upgrade")
+	end)
+
+	it("should keep current version when user declines upgrade", function()
+		local notifications = {}
+		local user_choices = {}
+
+		local exists_fn = function(filepath)
+			return filepath == "/data/junit-1.10.1.jar"
+		end
+
+		local checksum_fn = function(_file_path)
+			return version_1_10_1.sha256
+		end
+
+		local ask_user_consent_fn = function(message, choices, callback)
+			table.insert(user_choices, { message = message, choices = choices })
+			-- Simulate user choosing "No, keep current version"
+			callback("No, keep current version")
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return version_1_10_1, Path("/data/junit-1.10.1.jar")
+			end,
+			ask_user_consent = ask_user_consent_fn,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		-- Should have asked for upgrade
+		eq(1, #user_choices)
+
+		-- Should have notified about keeping current version
+		local keep_notification = false
+		for _, notif in ipairs(notifications) do
+			if notif.message:match("Keeping current") then
+				keep_notification = true
+				break
+			end
+		end
+		assert(keep_notification, "Should notify about keeping current version")
+	end)
+
+	it("should ask for download when no version exists", function()
+		local notifications = {}
+		local user_choices = {}
+		local downloads = {}
+
+		local exists_fn = function()
+			return false
+		end
+
+		local ask_user_consent_fn = function(message, choices, callback)
+			table.insert(user_choices, { message = message, choices = choices })
+			-- Simulate user choosing "Yes, download"
+			callback("Yes, download")
+		end
+
+		local download_fn = function(url, output)
+			table.insert(downloads, { url = url, output = output })
+			return { code = 0, stderr = "" }
+		end
+
+		local checksum_fn = function(_file_path)
+			return version_6_0_1.sha256
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return nil, nil
+			end,
+			ask_user_consent = ask_user_consent_fn,
+			download = download_fn,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		-- Should have asked for download
+		eq(1, #user_choices)
+		assert(user_choices[1].message:match("download"), "Should ask about download")
+
+		-- Should have downloaded
+		eq(1, #downloads)
+		assert(downloads[1].url:match("6%.0%.1"), "Should download version 6.0.1")
+
+		-- Should have notified about download
+		local download_notification = false
+		for _, notif in ipairs(notifications) do
+			if notif.message:match("Downloaded") then
+				download_notification = true
+				break
+			end
+		end
+		assert(download_notification, "Should notify about download")
+	end)
+
+	it("should handle download error", function()
+		local notifications = {}
+
+		local exists_fn = function()
+			return false
+		end
+
+		local ask_user_consent_fn = function(_message, _choices, callback)
+			callback("Yes, download")
+		end
+
+		local download_fn = function(_url, _output)
+			return { code = 1, stderr = "Network error" }
+		end
+
+		local deps = {
+			exists = exists_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return nil, nil
+			end,
+			ask_user_consent = ask_user_consent_fn,
+			download = download_fn,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		-- Should have error notification
+		local error_notification = false
+		for _, notif in ipairs(notifications) do
+			if notif.level == "error" or notif.message:match("Error") then
+				error_notification = true
+				break
+			end
+		end
+		assert(error_notification, "Should notify about error")
+	end)
+
+	it("should handle checksum verification failure", function()
+		local notifications = {}
+		local deleted_files = {}
+
+		local exists_fn = function()
+			return false
+		end
+
+		local ask_user_consent_fn = function(_message, _choices, callback)
+			callback("Yes, download")
+		end
+
+		local download_fn = function(_url, _output)
+			return { code = 0, stderr = "" }
+		end
+
+		local checksum_fn = function(_file_path)
+			-- Return wrong checksum
+			return "wrong_checksum"
+		end
+
+		local delete_file_fn = function(filepath)
+			table.insert(deleted_files, filepath)
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			notify = function(message, level)
+				table.insert(notifications, { message = message, level = level })
+			end,
+			detect_existing_version = function()
+				return nil, nil
+			end,
+			ask_user_consent = ask_user_consent_fn,
+			download = download_fn,
+			delete_file = delete_file_fn,
+		}
+
+		local installer = Installer(deps)
+		installer.install(default_config)
+
+		-- Should have deleted the file
+		eq(1, #deleted_files)
+
+		-- Should have error notification about checksum
+		local checksum_error = false
+		for _, notif in ipairs(notifications) do
+			if notif.message:match("Checksum") then
+				checksum_error = true
+				break
+			end
+		end
+		assert(checksum_error, "Should notify about checksum error")
+	end)
+end)
diff --git a/tests/unit/junit_version_detector_spec.lua b/tests/unit/junit_version_detector_spec.lua
new file mode 100644
index 00000000..ce33f91d
--- /dev/null
+++ b/tests/unit/junit_version_detector_spec.lua
@@ -0,0 +1,149 @@
+local version_detector = require("neotest-java.util.junit_version_detector")
+local Path = require("neotest-java.model.path")
+local eq = require("tests.assertions").eq
+
+describe("JUnit Version Detector", function()
+	it("should detect existing version by filename", function()
+		local version_6_0_1 = {
+			version = "6.0.1",
+			sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",
+		}
+		local version_1_10_1 = {
+			version = "1.10.1",
+			sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
+		}
+
+		-- Use Path to construct expected path (works on both Windows and Unix)
+		local data_dir_str = "data"
+		-- Build the path exactly the same way the detector does
+		local data_dir = Path(data_dir_str):append("neotest-java")
+		local expected_jar_path = data_dir:append("junit-platform-console-standalone-6.0.1.jar")
+
+		local exists_fn = function(filepath)
+			if filepath ~= expected_jar_path then
+				return false
+			end
+			return true
+		end
+
+		local checksum_fn = function(file_path)
+			local path_str = file_path:to_string()
+			-- Mock checksum based on path
+			if path_str:match("6%.0%.1") then
+				return version_6_0_1.sha256
+			elseif path_str:match("1%.10%.1") then
+				return version_1_10_1.sha256
+			end
+			return "unknown"
+		end
+
+		local deps = {
+			exists = exists_fn,
+			checksum = checksum_fn,
+			stdpath_data = function()
+				return data_dir_str
+			end,
+		}
+
+		local detected_version, filepath = version_detector.detect_existing_version(deps)
+
+		assert(detected_version ~= nil, "detected_version should not be nil")
+		eq(version_6_0_1.version, detected_version.version)
+		eq(version_6_0_1.sha256, detected_version.sha256)
+		-- Compare using Path to handle different path formats (Windows vs Unix)
+		eq(expected_jar_path, filepath)
+	end)
+
+	it("should return nil when no version is found", function()
+		local exists_fn = function(_filepath)
+			return false
+		end
+
+		local scan_fn = function()
+			return {}
+		end
+
+		local deps = {
+			exists = exists_fn,
+			scan = scan_fn,
+			stdpath_data = function()
+				return "data"
+			end,
+		}
+
+		local detected_version, filepath = version_detector.detect_existing_version(deps)
+
+		eq(nil, detected_version)
+		eq(nil, filepath)
+	end)
+
+	it("should detect version by checksum when filename doesn't match", function()
+		local version_1_10_1 = {
+			version = "1.10.1",
+			sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
+		}
+
+		local data_dir_str = "data"
+		local data_dir = Path(data_dir_str):append("neotest-java")
+		local jar_file = data_dir:append("custom-junit.jar")
+		local jar_file_str = jar_file:to_string()
+
+		local exists_fn = function(_filepath)
+			return false -- No file with expected filename
+		end
+
+		local scan_fn = function()
+			return { jar_file }
+		end
+
+		local checksum_fn = function(file_path)
+			-- Compare using Path to handle different path formats (Windows vs Unix)
+			local file_path_str = Path(file_path:to_string()):to_string()
+			if file_path_str == jar_file_str then
+				return version_1_10_1.sha256
+			end
+			return "unknown"
+		end
+
+		local deps = {
+			exists = exists_fn,
+			scan = scan_fn,
+			checksum = checksum_fn,
+			stdpath_data = function()
+				return data_dir_str
+			end,
+		}
+
+		local detected_version, filepath = version_detector.detect_existing_version(deps)
+
+		assert(detected_version ~= nil, "detected_version should not be nil")
+		eq(version_1_10_1.version, detected_version.version)
+		eq(version_1_10_1.sha256, detected_version.sha256)
+		-- Compare using Path to handle different path formats (Windows vs Unix)
+		eq(jar_file, filepath)
+	end)
+
+	it("should check for update when current version is older", function()
+		local current_version = {
+			version = "1.10.1",
+			sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
+		}
+
+		local has_update, latest_version = version_detector.check_for_update(current_version)
+
+		eq(true, has_update)
+		eq("6.0.1", latest_version.version)
+	end)
+
+	it("should not find update when current version is latest", function()
+		local current_version = {
+			version = "6.0.1",
+			sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",
+		}
+
+		local has_update, latest_version = version_detector.check_for_update(current_version)
+
+		eq(false, has_update)
+		eq(nil, latest_version)
+	end)
+end)

From 0ae7e2d0d33d889db7a83410ffffde111431f72b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Tue, 20 Jan 2026 23:35:04 +0100
Subject: [PATCH 3/6] fix: make windows compatible

---
 lua/neotest-java/install.lua | 30 +++++++++++++++++-------------
 tests/unit/install_spec.lua  | 36 +++++++++++++++++++++++++++++++++---
 2 files changed, 50 insertions(+), 16 deletions(-)

diff --git a/lua/neotest-java/install.lua b/lua/neotest-java/install.lua
index 25455d45..c27a1f04 100644
--- a/lua/neotest-java/install.lua
+++ b/lua/neotest-java/install.lua
@@ -1,6 +1,5 @@
 local logger = require("neotest-java.logger")
 local version_detector = require("neotest-java.util.junit_version_detector")
-local Path = require("neotest-java.model.path")
 
 ---@class neotest-java.InstallDeps
 ---@field exists fun(filepath: string): boolean
@@ -28,7 +27,7 @@ local Installer = function(deps)
 
 	--- Download JUnit jar for a specific version
 	--- @param version_info neotest-java.JunitVersion
-	--- @param target_filepath string
+	--- @param target_filepath neotest-java.Path
 	--- @return boolean success
 	local function download_junit_jar(version_info, target_filepath)
 		local url = ("https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console-standalone/%s/junit-platform-console-standalone-%s.jar"):format(
@@ -36,7 +35,8 @@ local Installer = function(deps)
 			version_info.version
 		)
 
-		local out = download_fn(url, target_filepath)
+		local target_filepath_str = target_filepath:to_string()
+		local out = download_fn(url, target_filepath_str)
 
 		if out.code ~= 0 then
 			notify_fn(string.format("Error while downloading: \n %s", out.stderr), "error")
@@ -44,7 +44,7 @@ local Installer = function(deps)
 			return false
 		end
 
-		local sha = checksum_fn(Path(target_filepath))
+		local sha = checksum_fn(target_filepath)
 		local expected_sha = version_info.sha256
 		if sha ~= expected_sha then
 			local message = ([[
@@ -53,9 +53,9 @@ local Installer = function(deps)
 				Got:      %s
 
 				Removed the file at %s.
-			]]):format(expected_sha, sha, target_filepath)
+			]]):format(expected_sha, sha, target_filepath_str)
 
-			delete_file_fn(target_filepath)
+			delete_file_fn(target_filepath_str)
 
 			notify_fn(message, "error")
 			logger.error(message)
@@ -68,13 +68,14 @@ local Installer = function(deps)
 	return {
 		--- @param config neotest-java.ConfigOpts
 		install = function(config)
-			local filepath = config.junit_jar:to_string()
-			local default_junit_jar_filepath = config.default_junit_jar_filepath:to_string()
+			local filepath = config.junit_jar
+			local default_junit_jar_filepath = config.default_junit_jar_filepath
+			local filepath_str = filepath:to_string()
 
 			-- Check if already installed with latest version
-			if exists_fn(filepath) then
+			if exists_fn(filepath_str) then
 				-- Verify it's the correct version by checksum
-				local current_sha = checksum_fn(Path(filepath))
+				local current_sha = checksum_fn(filepath)
 				if current_sha == config.default_junit_jar_version.sha256 then
 					notify_fn("JUnit jar is already set up with the latest version!")
 					return
@@ -111,7 +112,7 @@ local Installer = function(deps)
 									"Upgraded JUnit jar from %s to %s successfully at: \n%s",
 									existing_version.version,
 									latest_version.version,
-									default_junit_jar_filepath
+									default_junit_jar_filepath:to_string()
 								)
 							)
 						end
@@ -123,12 +124,15 @@ local Installer = function(deps)
 			end
 
 			-- If no existing version or user wants fresh install, download latest
-			if not existing_version or not exists_fn(filepath) then
+			if not existing_version or not exists_fn(filepath_str) then
 				local message = "JUnit Platform Console Standalone jar is required. Would you like to download it now?"
 				ask_user_consent_fn(message, { "Yes, download", "No, cancel" }, function(choice)
 					if choice == "Yes, download" then
 						if download_junit_jar(config.default_junit_jar_version, default_junit_jar_filepath) then
-							notify_fn("Downloaded JUnit Standalone successfully at: \n" .. default_junit_jar_filepath)
+							notify_fn(
+								"Downloaded JUnit Standalone successfully at: \n"
+									.. default_junit_jar_filepath:to_string()
+							)
 						end
 					else
 						notify_fn("Setup cancelled. You can run :NeotestJava setup later to download the JUnit jar.")
diff --git a/tests/unit/install_spec.lua b/tests/unit/install_spec.lua
index 35524369..59de986a 100644
--- a/tests/unit/install_spec.lua
+++ b/tests/unit/install_spec.lua
@@ -20,8 +20,10 @@ describe("Installer", function()
 
 	it("should notify when already set up with latest version", function()
 		local notifications = {}
+		local expected_path = Path("/data/junit-6.0.1.jar")
 		local exists_fn = function(filepath)
-			return filepath == "/data/junit-6.0.1.jar"
+			-- Compare paths using Path to handle Windows/Unix differences
+			return Path(filepath) == expected_path
 		end
 
 		local checksum_fn = function(_file_path)
@@ -37,6 +39,15 @@ describe("Installer", function()
 			detect_existing_version = function()
 				return nil, nil
 			end,
+			ask_user_consent = function(_message, _choices, callback)
+				callback("No, cancel")
+			end,
+			download = function(_url, _output)
+				return { code = 0, stderr = "" }
+			end,
+			delete_file = function(_filepath)
+				-- Mock delete
+			end,
 		}
 
 		local installer = Installer(deps)
@@ -51,9 +62,11 @@ describe("Installer", function()
 		local user_choices = {}
 		local downloads = {}
 
+		local expected_old_path = Path("/data/junit-1.10.1.jar")
 		local exists_fn = function(filepath)
 			-- Return true for old version, false for new version (not downloaded yet)
-			return filepath == "/data/junit-1.10.1.jar"
+			-- Compare paths using Path to handle Windows/Unix differences
+			return Path(filepath) == expected_old_path
 		end
 
 		local checksum_fn = function(file_path)
@@ -122,8 +135,10 @@ describe("Installer", function()
 		local notifications = {}
 		local user_choices = {}
 
+		local expected_old_path = Path("/data/junit-1.10.1.jar")
 		local exists_fn = function(filepath)
-			return filepath == "/data/junit-1.10.1.jar"
+			-- Compare paths using Path to handle Windows/Unix differences
+			return Path(filepath) == expected_old_path
 		end
 
 		local checksum_fn = function(_file_path)
@@ -146,6 +161,12 @@ describe("Installer", function()
 				return version_1_10_1, Path("/data/junit-1.10.1.jar")
 			end,
 			ask_user_consent = ask_user_consent_fn,
+			download = function(_url, _output)
+				return { code = 0, stderr = "" }
+			end,
+			delete_file = function(_filepath)
+				-- Mock delete
+			end,
 		}
 
 		local installer = Installer(deps)
@@ -200,6 +221,9 @@ describe("Installer", function()
 			end,
 			ask_user_consent = ask_user_consent_fn,
 			download = download_fn,
+			delete_file = function(_filepath)
+				-- Mock delete
+			end,
 		}
 
 		local installer = Installer(deps)
@@ -249,6 +273,12 @@ describe("Installer", function()
 			end,
 			ask_user_consent = ask_user_consent_fn,
 			download = download_fn,
+			checksum = function(_file_path)
+				return version_6_0_1.sha256
+			end,
+			delete_file = function(_filepath)
+				-- Mock delete
+			end,
 		}
 
 		local installer = Installer(deps)

From da9196f9b52099273a205d7054f11431a74f50c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Tue, 20 Jan 2026 23:49:44 +0100
Subject: [PATCH 4/6] refactor: make junit version detector a constructor
 method

---
 lua/neotest-java/init.lua                     |   3 +-
 lua/neotest-java/install.lua                  |   5 +-
 .../util/junit_version_detector.lua           | 116 ++++++++++--------
 tests/unit/junit_version_detector_spec.lua    |  27 ++--
 4 files changed, 86 insertions(+), 65 deletions(-)

diff --git a/lua/neotest-java/init.lua b/lua/neotest-java/init.lua
index 28d64553..773ee7f8 100644
--- a/lua/neotest-java/init.lua
+++ b/lua/neotest-java/init.lua
@@ -12,7 +12,8 @@ local Path = require("neotest-java.model.path")
 local nio = require("nio")
 local logger = require("neotest-java.logger")
 local Binaries = require("neotest-java.command.binaries")
-local version_detector = require("neotest-java.util.junit_version_detector")
+local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
+local version_detector = JunitVersionDetector()
 local lib = require("neotest.lib")
 local exists = require("neotest.lib.file").exists
 
diff --git a/lua/neotest-java/install.lua b/lua/neotest-java/install.lua
index c27a1f04..c93df08c 100644
--- a/lua/neotest-java/install.lua
+++ b/lua/neotest-java/install.lua
@@ -1,5 +1,6 @@
 local logger = require("neotest-java.logger")
-local version_detector = require("neotest-java.util.junit_version_detector")
+local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
+local version_detector = JunitVersionDetector()
 
 ---@class neotest-java.InstallDeps
 ---@field exists fun(filepath: string): boolean
@@ -8,7 +9,7 @@ local version_detector = require("neotest-java.util.junit_version_detector")
 ---@field delete_file fun(filepath: string): void
 ---@field ask_user_consent fun(message: string, choices: string[], callback: fun(choice: string | nil)): void
 ---@field notify fun(message: string, level?: string): void
----@field detect_existing_version fun(deps?: neotest-java.JunitVersionDetectorDeps): neotest-java.JunitVersion | nil, neotest-java.Path | nil
+---@field detect_existing_version fun(): neotest-java.JunitVersion | nil, neotest-java.Path | nil
 
 ---@class neotest-java.Installer
 ---@field install fun(config: neotest-java.ConfigOpts): void
diff --git a/lua/neotest-java/util/junit_version_detector.lua b/lua/neotest-java/util/junit_version_detector.lua
index d374fb10..bfb54b80 100644
--- a/lua/neotest-java/util/junit_version_detector.lua
+++ b/lua/neotest-java/util/junit_version_detector.lua
@@ -31,12 +31,17 @@ end
 ---@field scan? fun(dir: neotest-java.Path, opts: { search_patterns: string[] }): neotest-java.Path[]
 ---@field stdpath_data? fun(): string
 
---- Detect which version of JUnit jar exists in the data directory
+---@class neotest-java.JunitVersionDetector
+---@field detect_existing_version fun(): neotest-java.JunitVersion | nil, neotest-java.Path | nil
+---@field check_for_update fun(current_version: neotest-java.JunitVersion): boolean, neotest-java.JunitVersion | nil
+---@field get_supported_versions fun(): table[]
+---@field _checksum fun(file_path: neotest-java.Path, file_reader?: fun(path: string): string): string
+
 --- @param deps? neotest-java.JunitVersionDetectorDeps
---- @return neotest-java.JunitVersion | nil, neotest-java.Path | nil
--- Returns: version_info, filepath
-local function detect_existing_version(deps)
+--- @return neotest-java.JunitVersionDetector
+local JunitVersionDetector = function(deps)
 	deps = deps or {}
+
 	-- Create a wrapper for exists that accepts Path instead of string
 	local exists_fn = deps.exists or function(path)
 		return exists(path:to_string())
@@ -47,60 +52,71 @@ local function detect_existing_version(deps)
 	local scan_fn = deps.scan or require("neotest-java.util.dir_scan")
 	local stdpath_data_fn = deps.stdpath_data or vim.fn.stdpath
 
-	local supported_versions = get_supported_versions()
-	local data_dir = Path(stdpath_data_fn("data")):append("neotest-java")
-
-	-- First, try to detect by filename
-	for _, version_info in ipairs(supported_versions) do
-		local jar_path = data_dir:append("junit-platform-console-standalone-" .. version_info.version .. ".jar")
-		if exists_fn(jar_path) then
-			-- Verify by checksum to be sure
-			local file_sha = checksum_fn(jar_path)
-			if file_sha == version_info.sha256 then
-				return version_info, jar_path
+	return {
+		--- Detect which version of JUnit jar exists in the data directory
+		--- @return neotest-java.JunitVersion | nil, neotest-java.Path | nil
+		-- Returns: version_info, filepath
+		detect_existing_version = function()
+			local supported_versions = get_supported_versions()
+			local data_dir = Path(stdpath_data_fn("data")):append("neotest-java")
+
+			-- First, try to detect by filename
+			for _, version_info in ipairs(supported_versions) do
+				local jar_path = data_dir:append("junit-platform-console-standalone-" .. version_info.version .. ".jar")
+				if exists_fn(jar_path) then
+					-- Verify by checksum to be sure
+					local file_sha = checksum_fn(jar_path)
+					if file_sha == version_info.sha256 then
+						return version_info, jar_path
+					end
+				end
 			end
-		end
-	end
 
-	-- If not found by filename, try to detect by checksum
-	-- This handles cases where the file might have a different name
-	local ok, jar_files = pcall(function()
-		return scan_fn(data_dir, { search_patterns = { "junit-platform-console-standalone-.*%.jar" } })
-	end)
+			-- If not found by filename, try to detect by checksum
+			-- This handles cases where the file might have a different name
+			local ok, jar_files = pcall(function()
+				return scan_fn(data_dir, { search_patterns = { "junit-platform-console-standalone-.*%.jar" } })
+			end)
 
-	if ok and jar_files then
-		for _, jar_file in ipairs(jar_files) do
-			-- jar_file is a Path object
-			local file_sha = checksum_fn(jar_file)
-			for _, version_info in ipairs(supported_versions) do
-				if file_sha == version_info.sha256 then
-					return version_info, jar_file
+			if ok and jar_files then
+				for _, jar_file in ipairs(jar_files) do
+					-- jar_file is a Path object
+					local file_sha = checksum_fn(jar_file)
+					for _, version_info in ipairs(supported_versions) do
+						if file_sha == version_info.sha256 then
+							return version_info, jar_file
+						end
+					end
 				end
 			end
-		end
-	end
 
-	return nil, nil
-end
+			return nil, nil
+		end,
 
---- Check if there's a newer version available than the one currently installed
---- @param current_version neotest-java.JunitVersion
---- @return boolean, neotest-java.JunitVersion | nil
--- Returns: has_update, latest_version
-local function check_for_update(current_version)
-	local supported_versions = get_supported_versions()
-	local latest_version = supported_versions[1] -- First is always latest
+		--- Check if there's a newer version available than the one currently installed
+		--- @param current_version neotest-java.JunitVersion
+		--- @return boolean, neotest-java.JunitVersion | nil
+		-- Returns: has_update, latest_version
+		check_for_update = function(current_version)
+			local supported_versions = get_supported_versions()
+			local latest_version = supported_versions[1] -- First is always latest
 
-	if current_version.version ~= latest_version.version then
-		return true, latest_version
-	end
+			if current_version.version ~= latest_version.version then
+				return true, latest_version
+			end
+
+			return false, nil
+		end,
+
+		--- Get supported versions from default_config
+		--- @return table[]
+		get_supported_versions = get_supported_versions,
 
-	return false, nil
+		--- @param file_path neotest-java.Path
+		--- @param file_reader? fun(path: string): string
+		--- @return string hash
+		_checksum = checksum, -- Exposed for testing
+	}
 end
 
-return {
-	detect_existing_version = detect_existing_version,
-	check_for_update = check_for_update,
-	get_supported_versions = get_supported_versions,
-	_checksum = checksum, -- Exposed for testing
-}
+return JunitVersionDetector
diff --git a/tests/unit/junit_version_detector_spec.lua b/tests/unit/junit_version_detector_spec.lua
index ce33f91d..757bba01 100644
--- a/tests/unit/junit_version_detector_spec.lua
+++ b/tests/unit/junit_version_detector_spec.lua
@@ -1,8 +1,9 @@
-local version_detector = require("neotest-java.util.junit_version_detector")
+local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
 local Path = require("neotest-java.model.path")
 local eq = require("tests.assertions").eq
 
 describe("JUnit Version Detector", function()
+	local version_detector = JunitVersionDetector()
 	it("should detect existing version by filename", function()
 		local version_6_0_1 = {
 			version = "6.0.1",
@@ -37,15 +38,15 @@ describe("JUnit Version Detector", function()
 			return "unknown"
 		end
 
-		local deps = {
+		local detector = JunitVersionDetector({
 			exists = exists_fn,
 			checksum = checksum_fn,
 			stdpath_data = function()
 				return data_dir_str
 			end,
-		}
+		})
 
-		local detected_version, filepath = version_detector.detect_existing_version(deps)
+		local detected_version, filepath = detector.detect_existing_version()
 
 		assert(detected_version ~= nil, "detected_version should not be nil")
 		eq(version_6_0_1.version, detected_version.version)
@@ -63,15 +64,15 @@ describe("JUnit Version Detector", function()
 			return {}
 		end
 
-		local deps = {
+		local detector = JunitVersionDetector({
 			exists = exists_fn,
 			scan = scan_fn,
 			stdpath_data = function()
 				return "data"
 			end,
-		}
+		})
 
-		local detected_version, filepath = version_detector.detect_existing_version(deps)
+		local detected_version, filepath = detector.detect_existing_version()
 
 		eq(nil, detected_version)
 		eq(nil, filepath)
@@ -105,16 +106,16 @@ describe("JUnit Version Detector", function()
 			return "unknown"
 		end
 
-		local deps = {
+		local detector = JunitVersionDetector({
 			exists = exists_fn,
 			scan = scan_fn,
 			checksum = checksum_fn,
 			stdpath_data = function()
 				return data_dir_str
 			end,
-		}
+		})
 
-		local detected_version, filepath = version_detector.detect_existing_version(deps)
+		local detected_version, filepath = detector.detect_existing_version()
 
 		assert(detected_version ~= nil, "detected_version should not be nil")
 		eq(version_1_10_1.version, detected_version.version)
@@ -124,24 +125,26 @@ describe("JUnit Version Detector", function()
 	end)
 
 	it("should check for update when current version is older", function()
+		local detector = JunitVersionDetector()
 		local current_version = {
 			version = "1.10.1",
 			sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
 		}
 
-		local has_update, latest_version = version_detector.check_for_update(current_version)
+		local has_update, latest_version = detector.check_for_update(current_version)
 
 		eq(true, has_update)
 		eq("6.0.1", latest_version.version)
 	end)
 
 	it("should not find update when current version is latest", function()
+		local detector = JunitVersionDetector()
 		local current_version = {
 			version = "6.0.1",
 			sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",
 		}
 
-		local has_update, latest_version = version_detector.check_for_update(current_version)
+		local has_update, latest_version = detector.check_for_update(current_version)
 
 		eq(false, has_update)
 		eq(nil, latest_version)

From 6ef7cb2a12025619c3f52d61aac5422a3d0a457a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Wed, 21 Jan 2026 00:06:01 +0100
Subject: [PATCH 5/6] refactor: enhance JUnit Version Detector with dependency
 injection for better configurability

---
 lua/neotest-java/init.lua                     | 14 ++++++++-
 lua/neotest-java/install.lua                  | 15 ++++++++-
 .../util/junit_version_detector.lua           | 26 ++++++----------
 tests/unit/junit_version_detector_spec.lua    | 31 +++++++++++++++++--
 4 files changed, 64 insertions(+), 22 deletions(-)

diff --git a/lua/neotest-java/init.lua b/lua/neotest-java/init.lua
index 773ee7f8..c19f9e65 100644
--- a/lua/neotest-java/init.lua
+++ b/lua/neotest-java/init.lua
@@ -13,7 +13,19 @@ local nio = require("nio")
 local logger = require("neotest-java.logger")
 local Binaries = require("neotest-java.command.binaries")
 local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
-local version_detector = JunitVersionDetector()
+local version_detector = JunitVersionDetector({
+	exists = function(path)
+		return File.exists(path:to_string())
+	end,
+	checksum = function(path)
+		local f = assert(io.open(path:to_string(), "rb"))
+		local data = f:read("*a")
+		f:close()
+		return vim.fn.sha256(data)
+	end,
+	scan = require("neotest-java.util.dir_scan"),
+	stdpath_data = vim.fn.stdpath,
+})
 local lib = require("neotest.lib")
 local exists = require("neotest.lib.file").exists
 
diff --git a/lua/neotest-java/install.lua b/lua/neotest-java/install.lua
index c93df08c..9bd63e31 100644
--- a/lua/neotest-java/install.lua
+++ b/lua/neotest-java/install.lua
@@ -1,6 +1,19 @@
 local logger = require("neotest-java.logger")
 local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
-local version_detector = JunitVersionDetector()
+local exists = require("neotest.lib.file").exists
+local version_detector = JunitVersionDetector({
+	exists = function(path)
+		return exists(path:to_string())
+	end,
+	checksum = function(path)
+		local f = assert(io.open(path:to_string(), "rb"))
+		local data = f:read("*a")
+		f:close()
+		return vim.fn.sha256(data)
+	end,
+	scan = require("neotest-java.util.dir_scan"),
+	stdpath_data = vim.fn.stdpath,
+})
 
 ---@class neotest-java.InstallDeps
 ---@field exists fun(filepath: string): boolean
diff --git a/lua/neotest-java/util/junit_version_detector.lua b/lua/neotest-java/util/junit_version_detector.lua
index bfb54b80..300b02a3 100644
--- a/lua/neotest-java/util/junit_version_detector.lua
+++ b/lua/neotest-java/util/junit_version_detector.lua
@@ -1,5 +1,4 @@
 local Path = require("neotest-java.model.path")
-local exists = require("neotest.lib.file").exists
 
 local DEFAULT_CONFIG = require("neotest-java.default_config")
 
@@ -26,10 +25,10 @@ local function get_supported_versions()
 end
 
 ---@class neotest-java.JunitVersionDetectorDeps
----@field exists? fun(filepath: neotest-java.Path): boolean
----@field checksum? fun(file_path: neotest-java.Path): string
----@field scan? fun(dir: neotest-java.Path, opts: { search_patterns: string[] }): neotest-java.Path[]
----@field stdpath_data? fun(): string
+---@field exists fun(filepath: neotest-java.Path): boolean
+---@field checksum fun(file_path: neotest-java.Path): string
+---@field scan fun(dir: neotest-java.Path, opts: { search_patterns: string[] }): neotest-java.Path[]
+---@field stdpath_data fun(): string
 
 ---@class neotest-java.JunitVersionDetector
 ---@field detect_existing_version fun(): neotest-java.JunitVersion | nil, neotest-java.Path | nil
@@ -37,20 +36,13 @@ end
 ---@field get_supported_versions fun(): table[]
 ---@field _checksum fun(file_path: neotest-java.Path, file_reader?: fun(path: string): string): string
 
---- @param deps? neotest-java.JunitVersionDetectorDeps
+--- @param deps neotest-java.JunitVersionDetectorDeps
 --- @return neotest-java.JunitVersionDetector
 local JunitVersionDetector = function(deps)
-	deps = deps or {}
-
-	-- Create a wrapper for exists that accepts Path instead of string
-	local exists_fn = deps.exists or function(path)
-		return exists(path:to_string())
-	end
-	local checksum_fn = deps.checksum or function(path)
-		return checksum(path)
-	end
-	local scan_fn = deps.scan or require("neotest-java.util.dir_scan")
-	local stdpath_data_fn = deps.stdpath_data or vim.fn.stdpath
+	local exists_fn = deps.exists
+	local checksum_fn = deps.checksum
+	local scan_fn = deps.scan
+	local stdpath_data_fn = deps.stdpath_data
 
 	return {
 		--- Detect which version of JUnit jar exists in the data directory
diff --git a/tests/unit/junit_version_detector_spec.lua b/tests/unit/junit_version_detector_spec.lua
index 757bba01..92a2982a 100644
--- a/tests/unit/junit_version_detector_spec.lua
+++ b/tests/unit/junit_version_detector_spec.lua
@@ -3,7 +3,6 @@ local Path = require("neotest-java.model.path")
 local eq = require("tests.assertions").eq
 
 describe("JUnit Version Detector", function()
-	local version_detector = JunitVersionDetector()
 	it("should detect existing version by filename", function()
 		local version_6_0_1 = {
 			version = "6.0.1",
@@ -125,7 +124,20 @@ describe("JUnit Version Detector", function()
 	end)
 
 	it("should check for update when current version is older", function()
-		local detector = JunitVersionDetector()
+		local detector = JunitVersionDetector({
+			exists = function(_path)
+				return false
+			end,
+			checksum = function(_path)
+				return "dummy"
+			end,
+			scan = function()
+				return {}
+			end,
+			stdpath_data = function()
+				return "data"
+			end,
+		})
 		local current_version = {
 			version = "1.10.1",
 			sha256 = "b42eaa53d13576d17db5fb8b280722a6ae9e36daf95f4262bc6e96d4cb20725f",
@@ -138,7 +150,20 @@ describe("JUnit Version Detector", function()
 	end)
 
 	it("should not find update when current version is latest", function()
-		local detector = JunitVersionDetector()
+		local detector = JunitVersionDetector({
+			exists = function(_path)
+				return false
+			end,
+			checksum = function(_path)
+				return "dummy"
+			end,
+			scan = function()
+				return {}
+			end,
+			stdpath_data = function()
+				return "data"
+			end,
+		})
 		local current_version = {
 			version = "6.0.1",
 			sha256 = "3009120b7953bfe63add272e65b2bbeca0d41d0dfd8dea605201db15b640e0ff",

From 7eca04562b9993f14d72cf2a630bdcd78aa64b52 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ricardo=20Cas=C3=ADa?=
 <31012661+rcasia@users.noreply.github.com>
Date: Wed, 21 Jan 2026 18:22:50 +0100
Subject: [PATCH 6/6] WIP

---
 lua/neotest-java/init.lua | 67 ++++++++++++++++++++++++++++---------
 tests/unit/init_spec.lua  | 70 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 122 insertions(+), 15 deletions(-)

diff --git a/lua/neotest-java/init.lua b/lua/neotest-java/init.lua
index c19f9e65..d3370999 100644
--- a/lua/neotest-java/init.lua
+++ b/lua/neotest-java/init.lua
@@ -40,18 +40,6 @@ local build_tools = require("neotest-java.build_tool")
 local detect_project_type = require("neotest-java.util.detect_project_type")
 local compilers = require("neotest-java.core.spec_builder.compiler")
 
---- @param filepath neotest-java.Path
-local check_junit_jar = function(filepath, default_version)
-	local _exists, _ = File.exists(filepath:to_string())
-	assert(
-		_exists,
-		([[
-    Junit Platform Console Standalone jar not found at %s
-    Please run the following command to download it: NeotestJava setup
-    Or alternatively, download it from https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console-standalone/%s/junit-platform-console-standalone-%s.jar
-  ]]):format(filepath, default_version, default_version)
-	)
-end
 
 local mkdir = function(dir)
 	vim.uv.fs_mkdir(dir:to_string(), 493)
@@ -66,8 +54,13 @@ end
 --- @field install fun()
 ---
 
+---@class neotest-java.CheckJunitJarDeps
+---@field file_exists? fun(filepath: string): boolean
+---@field version_detector? neotest-java.JunitVersionDetector
+
 --- @class neotest-java.Dependencies
---- @field root_finder { find_root: fun(dir: string): string | nil }
+---@field root_finder? { find_root: fun(dir: string): string | nil }
+---@field check_junit_jar_deps? neotest-java.CheckJunitJarDeps
 
 --- @param config neotest-java.ConfigOpts
 --- @param deps? neotest-java.Dependencies
@@ -76,6 +69,7 @@ local function NeotestJavaAdapter(config, deps)
 	config = vim.tbl_extend("force", DEFAULT_CONFIG, config or {})
 	deps = deps or {}
 	local _root_finder = deps and deps.root_finder or root_finder
+	local check_junit_jar_deps = deps.check_junit_jar_deps or {}
 
 	log.info("neotest-java adapter initialized")
 
@@ -84,6 +78,46 @@ local function NeotestJavaAdapter(config, deps)
 	-- create data directory if it doesn't exist
 	mkdir(Path(vim.fn.stdpath("data")):append("neotest-java"))
 
+	-- Local function to check JUnit jar with dependencies from constructor
+	--- @param filepath neotest-java.Path
+	--- @param default_version string
+	--- @return neotest-java.Path
+	local check_junit_jar = function(filepath, default_version)
+		local file_exists_fn = check_junit_jar_deps.file_exists or File.exists
+		local _exists, _ = file_exists_fn(filepath:to_string())
+		if not _exists then
+			-- Try to detect if any supported version exists
+			local detector = check_junit_jar_deps.version_detector
+				or JunitVersionDetector({
+					exists = function(path)
+						return File.exists(path:to_string())
+					end,
+					checksum = function(path)
+						local f = assert(io.open(path:to_string(), "rb"))
+						local data = f:read("*a")
+						f:close()
+						return vim.fn.sha256(data)
+					end,
+					scan = require("neotest-java.util.dir_scan"),
+					stdpath_data = vim.fn.stdpath,
+				})
+			local detected_version, detected_filepath = detector.detect_existing_version()
+			if detected_version and detected_filepath then
+				-- Found a supported version, use it
+				return detected_filepath
+			end
+		end
+		assert(
+			_exists,
+			([[
+    Junit Platform Console Standalone jar not found at %s
+    Please run the following command to download it: NeotestJava setup
+    Or alternatively, download it from https://repo1.maven.org/maven2/org/junit/platform/junit-platform-console-standalone/%s/junit-platform-console-standalone-%s.jar
+  ]]):format(filepath, default_version, default_version)
+		)
+		return filepath
+	end
+
 	-- Check for JUnit jar updates (only if user hasn't disabled notifications and not already shown)
 	if not config.disable_update_notifications and not ch.update_notification_shown then
 		local existing_version, _ = version_detector.detect_existing_version()
@@ -202,8 +236,11 @@ local function NeotestJavaAdapter(config, deps)
 			return _root_finder.find_root(dir)
 		end,
 		build_spec = function(args)
-			check_junit_jar(config.junit_jar, config.default_junit_jar_version.version)
-			return spec_builder_instance.build_spec(args, config)
+			-- Check if the configured jar exists, if not try to detect any supported version
+			local actual_jar = check_junit_jar(config.junit_jar, config.default_junit_jar_version.version)
+			-- Create a config copy with the actual jar to use
+			local build_config = vim.tbl_extend("force", config, { junit_jar = actual_jar })
+			return spec_builder_instance.build_spec(args, build_config)
 		end,
 	}, {
 		__call = function(_, opts, user_deps)
diff --git a/tests/unit/init_spec.lua b/tests/unit/init_spec.lua
index 0fe06651..b3b52ae1 100644
--- a/tests/unit/init_spec.lua
+++ b/tests/unit/init_spec.lua
@@ -1,4 +1,6 @@
 local default_config = require("neotest-java.default_config")
+local Path = require("neotest-java.model.path")
+local JunitVersionDetector = require("neotest-java.util.junit_version_detector")
 local eq = assert.are.same
 
 describe("NeotestJava plugin", function()
@@ -14,6 +16,74 @@ describe("NeotestJava plugin", function()
 		end
 	end)
 
+	it("should use detected version when configured jar does not exist", function()
+		local Tree = require("neotest.types").Tree
+		local configured_path = Path("/data/junit-6.0.1.jar")
+		local detected_path = Path("/data/junit-1.10.1.jar")
+		local file_exists_calls = {}
+		local mock_detector = JunitVersionDetector({
+			exists = function(_path)
+				return false
+			end,
+			checksum = function(_path)
+				return "dummy"
+			end,
+			scan = function()
+				return {}
+			end,
+			stdpath_data = function()
+				return "data"
+			end,
+		})
+		-- Mock detect_existing_version to return a version
+		mock_detector.detect_existing_version = function()
+			return { version = "1.10.1", sha256 = "dummy" }, detected_path
+		end
+
+		local adapter = require("neotest-java")({
+			junit_jar = configured_path,
+		}, {
+			root_finder = {
+				find_root = function()
+					return "/some/root"
+				end,
+			},
+			check_junit_jar_deps = {
+				file_exists = function(filepath)
+					table.insert(file_exists_calls, filepath)
+					-- Configured jar doesn't exist
+					return false
+				end,
+				version_detector = mock_detector,
+			},
+		})
+
+		-- Create a minimal tree for testing
+		local tree = Tree.from_list({
+			id = "com.example.Test#testMethod()",
+			path = "/some/root/src/test/java/com/example/Test.java",
+			name = "testMethod",
+			type = "test",
+		}, function(x)
+			return x
+		end)
+
+		-- Try to call build_spec - this should trigger check_junit_jar
+		-- We expect it to fail because we don't have all dependencies, but it should call check_junit_jar first
+		pcall(function()
+			adapter.build_spec({ tree = tree })
+		end)
+
+		-- Verify that file_exists was called with the configured path when checking for the jar
+		assert(#file_exists_calls >= 1, "file_exists should be called at least once")
+		eq(configured_path:to_string(), file_exists_calls[1])
+
+		-- The adapter should be initialized successfully
+		assert(adapter ~= nil)
+		-- The config should still have the configured path (not modified during init)
+		eq(configured_path, adapter.config.junit_jar)
+	end)
+
 	it("does not throw when adapter is initialized outside of a java project", function()
 		--- @type neotest-java.Adapter
 		local adapter = require("neotest-java")({}, {