translate cache to configuration

Author: bruno-costanzo

lib/ruber.rb

@@ -4,7 +4,6 @@
 require "forwardable"
 require "ruber/configuration"
 require "ruber/authenticator"
-require "ruber/cache"
 
 # a Ruby wrapper for Uber API
 module Ruber
@@ -18,8 +17,8 @@ class << self
     extend Forwardable
 
     def_delegators(
-      :configuration, :customer_id, :client_id, :client_secret,
-      :customer_id=, :client_id=, :client_secret=, :cache_key, :cache_key=
+      :configuration, :customer_id, :client_id, :client_secret, :cache,
+      :customer_id=, :client_id=, :client_secret=, :cache_key, :cache_key=, :cache=
     )
   end
 end

lib/ruber/configuration.rb

@@ -1,10 +1,24 @@
 # frozen_string_literal: true
 
+require_relative "configuration/null_cache"
+
 module Ruber
   class Configuration
     attr_accessor :customer_id, :client_id, :client_secret
     attr_writer :cache_key
 
+    def cache
+      @cache ||= NullCache.new
+    end
+
+    def cache=(store)
+      unless %i[read write clear delete].all? { |method| store.respond_to?(method) }
+        raise ArgumentError, "cache_store must respond to read, write, clear, and delete"
+      end
+
+      @cache = store
+    end
+
     def cache_key
       @cache_key || "#{customer_id}_#{client_id}_access_token"
     end

lib/ruber/configuration/null_cache.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Ruber
+  class Configuration
+    class NullCache
+      def read(key) = memory_store[key]
+      def write(key, value, _options = {}) = memory_store[key] = value
+      def clear = memory_store.clear
+      def delete(key) = memory_store.delete(key)
+      def memory_store = @memory_store ||= {}
+    end
+  end
+end

test/ruber/configuration_test.rb

@@ -12,6 +12,14 @@ def setup
         cache_key: "custom_cache_key"
       }
 
+      @custom_cache = Class.new do
+        def read(key) = memory_store[key]
+        def write(key, value, _options = {}) = memory_store[key] = value
+        def clear = memory_store.clear
+        def delete(key) = memory_store.delete(key)
+        def memory_store = @memory_store ||= {}
+      end.new
+
       Ruber.configuration = nil
     end
 
@@ -66,6 +74,18 @@ def test_cache_key_can_be_set_explicitly
       assert_equal @config_values[:cache_key], Ruber.cache_key
     end
 
+    def test_cache_can_be_set_explicitly
+      Ruber.cache = @custom_cache
+
+      assert_equal @custom_cache, Ruber.cache
+    end
+
+    def test_cache_must_respond_to_read_write_clear_and_delete
+      assert_raises(ArgumentError) do
+        Ruber.cache = Object.new
+      end
+    end
+
     private
 
     def assert_configuration_values