Add test suite and CI workflow

[Copilot]

✅ Completed: Add Tests and CI Workflow

All tasks have been successfully completed:

• Create test file src/lib_test.ts with 42 comprehensive tests for core functions:
  • Test findClosestRationalAngle() function (7 tests)
  • Test gcd() function (7 tests)
  • Test lcm() function (5 tests)
  • Test calculateTileDimensions() function (6 tests)
  • Test validateDimensions() function (9 tests)
  • Test getOutputPath() function (5 tests)
  • Test RATIONAL_ANGLES constant (5 tests)
• Create GitHub Actions workflow file .github/workflows/test.yml to run tests on PRs
• Add test task to deno.json for easy test execution
• Add .gitignore to exclude build artifacts and test outputs
• Update README with testing instructions
• Address code review feedback
• Fix security vulnerabilities (add explicit permissions to workflow)
• Remove master branch from CI workflow (only main branch)
• Add --allow-env flag to fix Sharp library initialization error
• Add --allow-ffi flag to allow Sharp native bindings to load
• Fix test failures: normalize angles to -180/180 range and prevent duplicate errors for infinity
• Fix formatting and linting issues (remove unused imports)
• Fix typos in README documentation
• Apply code review feedback:
  • Remove unnecessary --allow-write permission from test task
  • Fix "pseudoelements" → "pseudo-elements" typos (2 instances)
  • Fix grammar "example. this" → "example, this"
  • Fix grammar "tile produces" → "tile produced"
  • Use join() for cross-platform path handling in getOutputPath()
  • Add @std/assert to deno.json imports for proper linting
  • Use SEPARATOR constant for proper cross-platform path prefix handling (`./ on POSIX, .\ on Windows)
  • Make path tests platform-agnostic using join() and SEPARATOR
  • Add specific expected values to calculateTileDimensions() tests (141x141 for 45° on 100x100, 447x224 for 26.565° on 100x200)

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add tests</issue_title>
<issue_description>We need to add tests to these functions and make sure CI runs them on each PR using github workflows.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add tests #5

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[marlonmarcello]

@copilot you can remove the master branch from the list in CI, also, we are getting the following error:

./src/lib_test.ts (uncaught error)
error: (in promise) NotCapable: Requires env access to "npm_package_config_libvips", run again with the --allow-env flag
const minimumLibvipsVersionLabelled = process.env.npm_package_config_libvips || config.libvips;
                                                  ^
    at Object.getEnv [as get] (ext:deno_os/30_os.js:124:10)
    at denoEnvGet (ext:deno_node/_process/process.ts:30:21)
    at Object.get (ext:deno_node/_process/process.ts:47:22)
    at file:///home/runner/.cache/deno/npm/registry.npmjs.org/sharp/0.34.5/lib/libvips.js:16:51
    at Object.<anonymous> (file:///home/runner/.cache/deno/npm/registry.npmjs.org/sharp/0.34.5/lib/libvips.js:209:3)
    at Module._compile (node:module:759:34)
    at loadMaybeCjs (node:module:784:10)
    at Object.Module._extensions..js (node:module:769:12)
    at Module.load (node:module:677:32)
    at Module._load (node:module:535:12)
This error was not caught from a test and caused the test runner to fail on the referenced module.
It most likely originated from a dangling promise, event/timeout handler or top-level code.

 FAILURES 

./src/lib_test.ts (uncaught error)

FAILED | 0 passed | 1 failed (0ms)

error: Test failed

[Copilot]

@copilot you can remove the master branch from the list in CI, also, we are getting the following error:

./src/lib_test.ts (uncaught error)

...

Fixed in commit ce42c01. Removed master branch from the workflow and added --allow-env flag to the test command to allow Sharp to access the required environment variables during initialization.

[marlonmarcello]

@copilot looks like we are missing sharp. Does CI install the correct deps?

Check src/lib_test.ts
Uncaught error from ./src/lib_test.ts FAILED

 ERRORS 

./src/lib_test.ts (uncaught error)
error: (in promise) Error: Could not load the "sharp" module using the linux-x64 runtime
undefined: Requires ffi access to "/home/runner/.cache/deno/npm/registry.npmjs.org/@img/sharp-linux-x64/0.34.5/lib/sharp-linux-x64.node", run again with the --allow-ffi flag
Possible solutions:
- Ensure optional dependencies can be installed:
    npm install --include=optional sharp
- Ensure your package manager supports multi-platform installation:
    See https://sharp.pixelplumbing.com/install#cross-platform
- Add platform-specific dependencies:
    npm install --os=linux --cpu=x64 sharp
- Consult the installation documentation:
    See https://sharp.pixelplumbing.com/install
  throw new Error(help.join('\n'));
        ^
    at file:///home/runner/.cache/deno/npm/registry.npmjs.org/sharp/0.34.5/lib/sharp.js:120:9
    at Object.<anonymous> (file:///home/runner/.cache/deno/npm/registry.npmjs.org/sharp/0.34.5/lib/sharp.js:123:3)
    at Module._compile (node:module:759:34)
    at loadMaybeCjs (node:module:784:10)
    at Object.Module._extensions..js (node:module:769:12)
    at Module.load (node:module:677:32)
    at Module._load (node:module:535:12)
    at Module.require (node:module:696:19)
    at require (node:module:830:16)
    at file:///home/runner/.cache/deno/npm/registry.npmjs.org/sharp/0.34.5/lib/constructor.js:10:1
This error was not caught from a test and caused the test runner to fail on the referenced module.
It most likely originated from a dangling promise, event/timeout handler or top-level code.

 FAILURES 

./src/lib_test.ts (uncaught error)

FAILED | 0 passed | 1 failed (0ms)

error: Test failed

[Copilot]

@copilot looks like we are missing sharp. Does CI install the correct deps?

Check src/lib_test.ts

...

Fixed in commit 44f2b90. Added --allow-ffi flag to allow Sharp to load its native bindings. Deno automatically installs npm dependencies from the imports in deno.json, so Sharp will be installed when tests run in CI.

[marlonmarcello]

@copilot we've got 3 failed tests

 ERRORS 

findClosestRationalAngle - normalizes negative angles => ./src/lib_test.ts:49:6
error: AssertionError: Values are not equal.


    [Diff] Actual / Expected


-   90
+   -45

  throw new AssertionError(message);
        ^
    at assertEquals (https://jsr.io/@std/assert/1.0.19/equals.ts:67:9)
    at file:///home/runner/work/wtc-tile-maker/wtc-tile-maker/src/lib_test.ts:51:3

validateDimensions - rejects infinite width => ./src/lib_test.ts:212:6
error: AssertionError: Values are not equal.


    [Diff] Actual / Expected


-   2
+   1

  throw new AssertionError(message);
        ^
    at assertEquals (https://jsr.io/@std/assert/1.0.19/equals.ts:67:9)
    at file:///home/runner/work/wtc-tile-maker/wtc-tile-maker/src/lib_test.ts:218:3

validateDimensions - rejects infinite height => ./src/lib_test.ts:222:6
error: AssertionError: Values are not equal.


    [Diff] Actual / Expected


-   2
+   1

  throw new AssertionError(message);
        ^
    at assertEquals (https://jsr.io/@std/assert/1.0.19/equals.ts:67:9)
    at file:///home/runner/work/wtc-tile-maker/wtc-tile-maker/src/lib_test.ts:228:3

 FAILURES 

findClosestRationalAngle - normalizes negative angles => ./src/lib_test.ts:49:6
validateDimensions - rejects infinite width => ./src/lib_test.ts:212:6
validateDimensions - rejects infinite height => ./src/lib_test.ts:222:6

FAILED | 39 passed | 3 failed (14ms)

error: Test failed

[Copilot]

@copilot we've got 3 failed tests

...

Fixed in commit 0ba863e. The failures were due to:

1. findClosestRationalAngle() was normalizing angles to 0-360 range, but should normalize to -180 to 180 to match the RATIONAL_ANGLES entries
2. validateDimensions() was producing duplicate errors for infinity (both infinity check and size check triggered) - now returns early after detecting infinity

[marlonmarcello]

@copilot looks like tests are passing now but not formatting or linting, make sure you run those every time.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 8 changed files in this pull request and generated 6 comments.

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[marlonmarcello]

@copilot looks like the last update changed the expected path, the test is failing:

 ERRORS 
getOutputPath - handles files in current directory => ./src/lib_test.ts:268:6
error: AssertionError: Values are not equal.
    [Diff] Actual / Expected
-   image-tile-90.png
+   ./image-tile-90.png

  throw new AssertionError(message);
        ^
    at assertEquals (https://jsr.io/@std/assert/1.0.19/equals.ts:67:9)
    at file:///home/runner/work/wtc-tile-maker/wtc-tile-maker/src/lib_test.ts:273:3
 FAILURES 
getOutputPath - handles files in current directory => ./src/lib_test.ts:268:6
FAILED | 41 passed | 1 failed (13ms)
error: Test failed

[Copilot]

@copilot looks like the last update changed the expected path, the test is failing:

 ERRORS 

...

Fixed in commit 3d1197d. The join() function was removing the ./ prefix for files in the current directory. Updated getOutputPath() to explicitly preserve the ./ prefix when dirname() returns "." while still using join() for cross-platform compatibility on other paths.

[marlonmarcello]

@copilot looks like the last update changed the expected path, the test is failing:

 ERRORS 

...

Fixed in commit 3d1197d. The join() function was removing the ./ prefix for files in the current directory. Updated getOutputPath() to explicitly preserve the ./ prefix when dirname() returns "." while still using join() for cross-platform compatibility on other paths.

@copilot the return is now return inputDir === "." ? ./${outputFileName} : outputPath;, it seems that you hard coded ./, didn't we update to use join() so that we explicitly avoided that so we could support windows? Wouldn't hard coding like this break it?

[Copilot]

Pull request overview

Copilot reviewed 6 out of 8 changed files in this pull request and generated 2 comments.

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[marlonmarcello]

@copilot apply changes based on the comments in this thread

[Copilot]

@copilot looks like the last update changed the expected path, the test is failing:

 ERRORS 

...

You're absolutely right! Fixed in commit 97bb6da. The hardcoded ./ would break on Windows where the separator is \. Now using SEPARATOR constant from @std/path which automatically uses / on POSIX systems (Linux, macOS) and \ on Windows. The code now properly generates ./file.png on POSIX and .\file.png on Windows.

[Copilot]

@copilot apply changes based on the comments in this thread

Fixed in commit 83130e2:

• Made path tests platform-agnostic by using join() from @std/path to construct expected paths instead of hardcoded / separators
• Used SEPARATOR constant for the current directory test case (.${SEPARATOR} produces ./ on POSIX, .\ on Windows)
• Added specific expected dimensions to calculateTileDimensions() tests: 141x141 for 45° on 100x100 image, and 447x224 for 26.565° on 100x200 image

[Copilot]

Pull request overview

Copilot reviewed 6 out of 8 changed files in this pull request and generated 1 comment.

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