Add tests for git reference resolution functions

__tests__/git-resolve.test.ts

@@ -0,0 +1,95 @@
+import * as git from '../src/git'
+import * as exec from '@actions/exec'
+
+jest.mock('@actions/exec')
+const mockedGetExecOutput = jest.mocked(exec.getExecOutput)
+
+beforeEach(() => {
+  mockedGetExecOutput.mockReset()
+})
+
+describe('resolveRefToSha', () => {
+  test('resolves a branch name to its commit SHA', async () => {
+    mockedGetExecOutput.mockResolvedValue({
+      exitCode: 0,
+      stdout: '8b399ed1681b9efd6b1e048ca1c5cba47edf3855\n',
+      stderr: ''
+    })
+    const sha = await git.resolveRefToSha('master')
+    expect(sha).toBe('8b399ed1681b9efd6b1e048ca1c5cba47edf3855')
+    expect(mockedGetExecOutput).toHaveBeenCalledWith('git', ['rev-parse', 'master'])
+  })
+
+  test('resolves a tag to its commit SHA', async () => {
+    mockedGetExecOutput.mockResolvedValue({
+      exitCode: 0,
+      stdout: '8b399ed1681b9efd6b1e048ca1c5cba47edf3855\n',
+      stderr: ''
+    })
+    const sha = await git.resolveRefToSha('release-18')
+    expect(sha).toBe('8b399ed1681b9efd6b1e048ca1c5cba47edf3855')
+    expect(mockedGetExecOutput).toHaveBeenCalledWith('git', ['rev-parse', 'release-18'])
+  })
+
+  test('returns SHA as-is when given a full SHA', async () => {
+    const fullSha = '8b399ed1681b9efd6b1e048ca1c5cba47edf3855'
+    mockedGetExecOutput.mockResolvedValue({
+      exitCode: 0,
+      stdout: `${fullSha}\n`,
+      stderr: ''
+    })
+    const sha = await git.resolveRefToSha(fullSha)
+    expect(sha).toBe(fullSha)
+  })
+})
+
+describe('isBaseSameAsHead with SHA comparison', () => {
+  test('different ref names pointing to same commit are treated as same', async () => {
+    const sameSha = '8b399ed1681b9efd6b1e048ca1c5cba47edf3855'
+    mockedGetExecOutput.mockResolvedValue({
+      exitCode: 0,
+      stdout: `${sameSha}\n`,
+      stderr: ''
+    })
+
+    const base: string = 'master'
+    const head: string = 'release-18'
+    const baseSha = await git.resolveRefToSha(base)
+    const headSha = await git.resolveRefToSha(head)
+    const isBaseSameAsHead = base === head || baseSha === headSha
+
+    expect(base === head).toBe(false) // ref names differ
+    expect(isBaseSameAsHead).toBe(true) // but SHAs match
+  })
+
+  test('different ref names pointing to different commits are not same', async () => {
+    mockedGetExecOutput
+      .mockResolvedValueOnce({
+        exitCode: 0,
+        stdout: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n',
+        stderr: ''
+      })
+      .mockResolvedValueOnce({
+        exitCode: 0,
+        stdout: 'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n',
+        stderr: ''
+      })
+
+    const base: string = 'master'
+    const head: string = 'feature/xyz'
+    const baseSha = await git.resolveRefToSha(base)
+    const headSha = await git.resolveRefToSha(head)
+    const isBaseSameAsHead = base === head || baseSha === headSha
+
+    expect(isBaseSameAsHead).toBe(false)
+  })
+
+  test('same ref names are detected without SHA resolution', async () => {
+    const base: string = 'master'
+    const head: string = 'master'
+    const isBaseSameAsHead = base === head
+
+    expect(isBaseSameAsHead).toBe(true)
+    expect(mockedGetExecOutput).not.toHaveBeenCalled()
+  })
+})