Change detection using git "three dot" diff

.github/workflows/pull-request-verification.yml

@@ -75,7 +75,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - run: touch add.txt && rm README.md && echo "TEST" > LICENSE && git add -A
+    - name: configure GIT user
+      run: git config user.email "john@nowhere.local" && git config user.name "John Doe"
+    - name: modify working tree
+      run: touch add.txt && rm README.md && echo "TEST" > LICENSE
+    - name: commit changes
+      run: git add -A && git commit -a -m 'testing this action'
     - uses: ./
       id: filter
       with:

__tests__/git.test.ts

@@ -1,18 +1,11 @@
 import * as git from '../src/git'
-import {ExecOptions} from '@actions/exec'
 import {ChangeStatus} from '../src/file'
 
-describe('parsing of the git diff-index command', () => {
-  test('getChangedFiles returns files with correct change status', async () => {
-    const files = await git.getChangedFiles(git.FETCH_HEAD, (cmd, args, opts) => {
-      const stdout = opts?.listeners?.stdout
-      if (stdout) {
-        stdout(Buffer.from('A\u0000LICENSE\u0000'))
-        stdout(Buffer.from('M\u0000src/index.ts\u0000'))
-        stdout(Buffer.from('D\u0000src/main.ts\u0000'))
-      }
-      return Promise.resolve(0)
-    })
+describe('parsing output of the git diff command', () => {
+  test('parseGitDiffOutput returns files with correct change status', async () => {
+    const files = git.parseGitDiffOutput(
+      'A\u0000LICENSE\u0000' + 'M\u0000src/index.ts\u0000' + 'D\u0000src/main.ts\u0000'
+    )
     expect(files.length).toBe(3)
     expect(files[0].filename).toBe('LICENSE')
     expect(files[0].status).toBe(ChangeStatus.Added)

action.yml

@@ -17,15 +17,23 @@ inputs:
     required: false
   filters:
     description: 'Path to the configuration file or YAML string with filters definition'
-    required: false
+    required: true
   list-files:
     description: |
       Enables listing of files matching the filter:
         'none'  - Disables listing of matching files (default).
         'json'  - Matching files paths are serialized as JSON array.
         'shell' - Matching files paths are escaped and space-delimited. Output is usable as command line argument list in linux shell.
-    required: false
+    required: true
     default: none
+  initial-fetch-depth:
+    description: |
+      How many commits are initially fetched from base branch.
+      If needed, each subsequent fetch doubles the previously requested number of commits
+      until the merge-base is found or there are no more commits in the history.
+      This option takes effect only when changes are detected using git against different base branch.
+    required: false
+    default: '10'
 runs:
   using: 'node12'
   main: 'dist/index.js'