test: add unit tests for src/main.ts

[Neev213]

Summary

Adds src/main.test.ts with comprehensive unit tests for the main module functions.

Changes

• New file: src/main.test.ts with vitest tests covering:

parseVersionFile()

• Trimming whitespace from version strings
• Stripping leading v prefix when followed by a digit (e.g., v0.2.0 → 0.2.0)
• Not stripping v when not followed by a digit (e.g., version-1.0.0 stays unchanged)
• Edge cases: empty strings, newlines, pre-release versions (v1.2.3-rc1)

strToBoolean()

• Truthy values: true, yes, 1, uppercase variants
• Falsy values: false, no, 0, '', undefined, null
• Case-insensitivity handling

getVersion()

• Parsing version from v version stdout output
• Throwing on stderr output
• Returning fallback 0.0.0 when stdout is empty

resolveVersionInput()

• Reading version directly from version input
• Reading from version-file when specified
• Throwing when version-file does not exist
• Warning when both version and version-file are specified
• Stripping v prefix from version-file contents

Cache logic (via run())

• Cache key generation: v-{version}-{platform}-{arch} format
• Cache hit path: Early return with cached outputs, no download
• Cache miss path: Downloads V, caches it, sets all outputs
• Skipping cache when cache input is false or version is not provided
• Architecture-specific cache keys

Error handling

• core.setFailed() called when run() throws
• Warning emitted when architecture is set but version is missing

Related issue

Closes #28

[ulises-jeremias]

Thanks @Neev213 for the comprehensive test suite (539 lines)! The CI build is failing because of a vitest mocking issue: the vi.mock factory functions reference top-level variables, which vitest does not support since vi.mock factories are hoisted above all imports.

To fix: use vi.hoisted to define mocks that can be referenced inside vi.mock factories:

const mockCore = vi.hoisted(() => ({ getInput: vi.fn(), ... }));
vi.mock("@actions/core", () => mockCore);

Once the build passes, this is the most comprehensive test suite for src/main.ts and we would love to merge it!

[ulises-jeremias]

Hey @Neev213! 👋 Thanks for picking up #28. Heads-up that #66 from @ifauzeee is working on the same issue with a more complete change set (modifies src/main.ts too and refreshes the dist/ bundle). Would you mind coordinating with them so we don't merge competing test rewrites?\n\nIf you'd like to keep this PR, consider:\n1. Rebasing off the latest main once any of these lands,\n2. Adapting to whatever shape the src/main.ts API takes after #66's refactor (you call getVersion, parseVersionFile, strToBoolean, resolveVersionInput, etc. — ifauzeee's version stripped some), and\n3. Re-running the build check (build is currently failing here).\n\nOtherwise feel free to close in favor of #66 once it merges — either way, super valuable first contribution!