ci: Add unit tests required check

.github/file-filters.yml

@@ -15,3 +15,27 @@ high_risk_code: &high_risk_code
   - "Sources/Sentry/SentryFileManager.m"
   - "Sources/Sentry/SentrySerialization.m"
   - "Sources/Sentry/SentrySerialization.h"
+
+run_unit_tests_for_prs: &run_unit_tests_for_prs # Code
+  - "Sources/**"
+  - "Tests/**"
+  - "SentryTestUtils/**"
+  - "SentryTestUtilsDynamic/**"
+
+  # GH Actions
+  - ".github/workflows/test.yml"
+  - ".github/file-filters.yml"
+
+  # Scripts
+  - "scripts/ci-select-xcode.sh"
+  - "scripts/sentry-xcodebuild.sh"
+  - "scripts/tests-with-thread-sanitizer.sh"
+
+  # Other
+  - "test-server/**"
+  - "Sentry.xcodeproj"
+  - "**/*.xctestplan"
+  - "fastlane/**"
+  - ".codecov.yml"
+  - "Brewfile*" # Dependency installation affects test environment
+  - "Makefile" # Make commands used for CI build setup

.github/workflows/test.yml

@@ -6,31 +6,36 @@ on:
       - release/**
 
   pull_request:
-    paths:
-      - "Sources/**"
-      - "Tests/**"
-      - "SentryTestUtils/**"
-      - "SentryTestUtilsDynamic/**" # Dynamic test utilities used by tests
-      - "test-server/**"
-      - ".github/workflows/test.yml"
-      - "fastlane/**"
-      - "scripts/tests-with-thread-sanitizer.sh"
-      - "scripts/ci-select-xcode.sh"
-      - "scripts/sentry-xcodebuild.sh"
-      - ".codecov.yml"
-      - "Sentry.xcodeproj"
-      - "**/*.xctestplan"
-      - "Makefile" # Make commands used for CI build setup
-      - "Brewfile*" # Dependency installation affects test environment
 
 # https://docs.github.com/en/actions/using-jobs/using-concurrency#example-using-a-fallback-value
 concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
 
 jobs:
+  # This job detects if the PR contains changes that require running unit tests.
+  # If yes, the job will output a flag that will be used by the next job to run the unit tests.
+  # If no, the job will output a flag that will be used by the next job to skip running the unit tests.
+  # At the end of this workflow, we run a check that validates that either all unit tests passed or were
+  # called unit-tests-required-check.
+  files-changed:
+    name: Detect File Changes
+    runs-on: ubuntu-latest
+    # Map a step output to a job output
+    outputs:
+      run_unit_tests_for_prs: ${{ steps.changes.outputs.run_unit_tests_for_prs }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Get changed files
+        id: changes
+        uses: dorny/paths-filter@de90cc6fb38fc0963ad72b210f1f284cd68cea36 # v3.0.2
+        with:
+          token: ${{ github.token }}
+          filters: .github/file-filters.yml
   build-test-server:
     name: Build test server
+    if: needs.files-changed.outputs.run_unit_tests_for_prs == 'true'
+    needs: files-changed
     runs-on: macos-15
     steps:
       - uses: actions/checkout@v4
@@ -300,3 +305,25 @@ jobs:
           verbose: true
           name: sentry-cocoa-unit-tests
           flags: unittests-${{ matrix.platform }}-${{ matrix.xcode }}-${{ matrix.test-destination-os }}, unittests
+
+  # This check validates that either all unit tests passed or were skipped, which allows us
+  # to make unit tests a required check with only running the unit tests when required.
+  # So, we don't have to run unit tests, for example, for Changelog or ReadMe changes.
+
+  unit-tests-required-check:
+    needs:
+      [
+        build-test-server,
+        unit-tests,
+      ]
+    name: Unit Tests
+    # This is necessary since a failed/skipped dependent job would cause this job to be skipped
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      # If any jobs we depend on fails gets cancelled or times out, this job will fail.
+      # Skipped jobs are not considered failures.
+      - name: Check for failures
+        if: contains(needs.*.result, 'failure') || contains(needs.*.result, 'cancelled')
+        run: |
+          echo "One of the unit test jobs has failed." && exit 1