feat(ci): shard test suite and enable JUnit 5 parallel execution (#4977)

.github/actions/gradle-setup/action.yml

@@ -13,6 +13,10 @@ inputs:
 runs:
   using: composite
   steps:
+    - name: Copy CI Gradle properties
+      shell: bash
+      run: mkdir -p ~/.gradle && cp .github/ci-gradle.properties ~/.gradle/gradle.properties
+
     - name: Validate Gradle Wrapper
       uses: gradle/actions/wrapper-validation@v6
 
@@ -29,7 +33,4 @@ runs:
         cache-read-only: ${{ inputs.cache_read_only }}
         cache-encryption-key: ${{ inputs.gradle_encryption_key }}
         cache-cleanup: on-success
-        build-scan-publish: true
-        build-scan-terms-of-use-url: 'https://gradle.com/terms-of-service'
-        build-scan-terms-of-use-agree: 'yes'
         add-job-summary: always

.github/ci-gradle.properties

@@ -0,0 +1,52 @@
+#
+# CI-specific Gradle properties.
+#
+# This file is copied to ~/.gradle/gradle.properties by the gradle-setup
+# composite action, overriding the dev-oriented values in the repo-root
+# gradle.properties. Inspired by the nowinandroid & sqldelight patterns.
+#
+
+# ── Daemon ────────────────────────────────────────────────────────────
+# Single-use CI runners never reuse a daemon, so the startup cost is pure
+# overhead. Disabling it also avoids "daemon disappeared" warnings.
+org.gradle.daemon=false
+
+# ── Memory ────────────────────────────────────────────────────────────
+# Standard GitHub runners have 7 GB RAM. Keep Gradle + Kotlin daemon
+# within budget (4g Gradle + 2g Kotlin daemon + 1g OS/tooling headroom).
+org.gradle.jvmargs=-Xmx4g -XX:+UseParallelGC -XX:MaxMetaspaceSize=1g -Dfile.encoding=UTF-8
+kotlin.daemon.jvm.options=-Xmx2g -XX:+UseParallelGC
+
+# ── Parallelism ───────────────────────────────────────────────────────
+org.gradle.parallel=true
+org.gradle.workers.max=4
+
+# ── Caching & Configuration ──────────────────────────────────────────
+org.gradle.caching=true
+org.gradle.configuration-cache=true
+org.gradle.configureondemand=false
+org.gradle.vfs.watch=false
+org.gradle.isolated-projects=true
+
+# ── Kotlin ────────────────────────────────────────────────────────────
+# Incremental compilation is wasted on fresh CI checkouts (no prior build
+# state to diff against). Disabling avoids the overhead of maintaining
+# incremental state that will never be reused.
+kotlin.incremental=false
+kotlin.code.style=official
+kotlin.parallel.tasks.in.project=true
+
+# ── KSP ──────────────────────────────────────────────────────────────
+# In CI, KSP incremental processing adds overhead without benefit (fresh
+# checkouts). Keep intermodule incremental off (no prior state).
+ksp.incremental=false
+ksp.run.in.process=true
+
+# ── Android ──────────────────────────────────────────────────────────
+android.experimental.lint.analysisPerComponent=true
+# Disable unused build features to reduce build time
+android.defaults.buildfeatures.resvalues=false
+android.defaults.buildfeatures.shaders=false
+
+# ── Misc ─────────────────────────────────────────────────────────────
+org.gradle.welcome=never

.github/workflows/pull-request.yml

@@ -99,15 +99,16 @@ jobs:
           PY
 
   # 2. VALIDATION & BUILD: Delegate to reusable-check.yml
-  # We disable instrumented tests for PRs to keep feedback fast (< 10 mins).
+  # We disable instrumented tests and coverage for PRs to keep feedback fast (< 10 mins).
   validate-and-build:
-    needs: [check-changes, verify-check-changes-filter]
+    needs: check-changes
     if: needs.check-changes.outputs.android == 'true'
     uses: ./.github/workflows/reusable-check.yml
     with:
       run_lint: true
       run_unit_tests: true
       run_instrumented_tests: false
+      run_coverage: false
       api_levels: '[35]'
       upload_artifacts: true
     secrets: inherit

.github/workflows/release.yml

@@ -113,11 +113,6 @@ jobs:
       GRADLE_CACHE_URL: ${{ secrets.GRADLE_CACHE_URL }}
       GRADLE_CACHE_USERNAME: ${{ secrets.GRADLE_CACHE_USERNAME }}
       GRADLE_CACHE_PASSWORD: ${{ secrets.GRADLE_CACHE_PASSWORD }}
-      GRADLE_OPTS: >-
-        -Dorg.gradle.jvmargs=-Xmx4g -XX:+UseParallelGC -XX:MaxMetaspaceSize=1g -Dfile.encoding=UTF-8
-        -Dorg.gradle.vfs.watch=false
-        -Dorg.gradle.workers.max=4
-        -Dkotlin.daemon.jvm.options=-Xmx2g -XX:+UseParallelGC
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
@@ -203,11 +198,6 @@ jobs:
       GRADLE_CACHE_URL: ${{ secrets.GRADLE_CACHE_URL }}
       GRADLE_CACHE_USERNAME: ${{ secrets.GRADLE_CACHE_USERNAME }}
       GRADLE_CACHE_PASSWORD: ${{ secrets.GRADLE_CACHE_PASSWORD }}
-      GRADLE_OPTS: >-
-        -Dorg.gradle.jvmargs=-Xmx4g -XX:+UseParallelGC -XX:MaxMetaspaceSize=1g -Dfile.encoding=UTF-8
-        -Dorg.gradle.vfs.watch=false
-        -Dorg.gradle.workers.max=4
-        -Dkotlin.daemon.jvm.options=-Xmx2g -XX:+UseParallelGC
     steps:
       - name: Checkout code
         uses: actions/checkout@v6

.github/workflows/reusable-check.yml

@@ -12,6 +12,9 @@ on:
       run_instrumented_tests:
         type: boolean
         default: true
+      run_coverage:
+        type: boolean
+        default: true
       api_levels:
         type: string
         default: '[35]'
@@ -44,29 +47,28 @@ env:
   GRADLE_CACHE_URL: ${{ secrets.GRADLE_CACHE_URL }}
   GRADLE_CACHE_USERNAME: ${{ secrets.GRADLE_CACHE_USERNAME }}
   GRADLE_CACHE_PASSWORD: ${{ secrets.GRADLE_CACHE_PASSWORD }}
-  # CI JVM tuning: override gradle.properties values (8g heap + 4g Kotlin daemon)
-  # that exceed the 7GB RAM on ubuntu-24.04 standard runners.
-  GRADLE_OPTS: >-
-    -Dorg.gradle.jvmargs=-Xmx4g -XX:+UseParallelGC -XX:MaxMetaspaceSize=1g -Dfile.encoding=UTF-8
-    -Dorg.gradle.vfs.watch=false
-    -Dorg.gradle.workers.max=4
-    -Dkotlin.daemon.jvm.options=-Xmx2g -XX:+UseParallelGC
+  # Fallback VERSION_CODE for the lint-check job itself (which computes the real
+  # value from git). Downstream jobs override this with the git-derived value.
+  VERSION_CODE: ${{ github.run_number }}
 
 jobs:
-  host-check:
+  # ── Lint & Static Analysis ──────────────────────────────────────────
+  lint-check:
     runs-on: ubuntu-24.04
     permissions:
       contents: read
-    timeout-minutes: 60
+    timeout-minutes: 30
     outputs:
       cache_read_only: ${{ steps.cache_config.outputs.cache_read_only }}
+      version_code: ${{ steps.version_code.outputs.version_code }}
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
         with:
           fetch-depth: 0
-          submodules: 'recursive'
+          filter: 'blob:none'
+          submodules: true
 
       - name: Determine cache read-only setting
         id: cache_config
@@ -78,64 +80,172 @@ jobs:
             echo "cache_read_only=true" >> "$GITHUB_OUTPUT"
           fi
 
+      - name: Calculate version code from git commit count
+        id: version_code
+        shell: bash
+        run: |
+          COMMIT_COUNT=$(git rev-list --count HEAD)
+          OFFSET=$(grep '^VERSION_CODE_OFFSET=' config.properties | cut -d'=' -f2 || echo 0)
+          VERSION_CODE=$((COMMIT_COUNT + OFFSET))
+          echo "version_code=$VERSION_CODE" >> "$GITHUB_OUTPUT"
+
       - name: Gradle Setup
         uses: ./.github/actions/gradle-setup
         with:
           gradle_encryption_key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
           cache_read_only: ${{ steps.cache_config.outputs.cache_read_only }}
 
-      - name: Code Style & Static Analysis
+      - name: Lint, Analysis & KMP Smoke Compile
         if: inputs.run_lint == true
-        run: ./gradlew spotlessCheck detekt -Pci=true --scan
+        run: ./gradlew spotlessCheck detekt app:lintFdroidDebug app:lintGoogleDebug core:barcode:lintFdroidDebug core:barcode:lintGoogleDebug core:api:lintDebug mesh_service_example:lintDebug kmpSmokeCompile -Pci=true --continue --scan
 
-      - name: Android Lint
-        if: inputs.run_lint == true
-        run: ./gradlew app:lintFdroidDebug app:lintGoogleDebug core:barcode:lintFdroidDebug core:barcode:lintGoogleDebug core:api:lintDebug mesh_service_example:lintDebug -Pci=true --continue --scan
-
-      - name: Shared Unit Tests & Coverage
-        if: inputs.run_unit_tests == true
-        run: ./gradlew test allTests koverXmlReport app:koverXmlReportFdroidDebug app:koverXmlReportGoogleDebug core:api:koverXmlReportDebug core:barcode:koverXmlReportFdroidDebug core:barcode:koverXmlReportGoogleDebug mesh_service_example:koverXmlReportDebug desktop:koverXmlReport -Pci=true --continue --scan
-
-      - name: KMP Smoke Compile
+      - name: KMP Smoke Compile (lint skipped)
+        if: inputs.run_lint == false
         run: ./gradlew kmpSmokeCompile -Pci=true --continue --scan
 
-      - name: Upload coverage results to Codecov
-        if: ${{ !cancelled() && inputs.run_unit_tests }}
-        uses: codecov/codecov-action@v6
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          slug: meshtastic/Meshtastic-Android
-          flags: host-unit
-          fail_ci_if_error: false
-          files: "**/build/reports/kover/report*.xml"
+  # ── Sharded Unit Tests ──────────────────────────────────────────────
+  # Tests are split into 3 shards that run in parallel:
+  #   shard-core:    core:* KMP module tests (allTests)
+  #   shard-feature: feature:* KMP module tests (allTests)
+  #   shard-app:     Pure-Android/JVM tests (app, desktop, core:barcode, etc.)
+  test-shards:
+    runs-on: ubuntu-24.04
+    permissions:
+      contents: read
+    timeout-minutes: 45
+    needs: lint-check
+    if: inputs.run_unit_tests == true
+    env:
+      VERSION_CODE: ${{ needs.lint-check.outputs.version_code }}
+    strategy:
+      fail-fast: false
+      matrix:
+        shard:
+          - name: shard-core
+            tasks: >-
+              :core:ble:allTests
+              :core:common:allTests
+              :core:data:allTests
+              :core:database:allTests
+              :core:domain:allTests
+              :core:model:allTests
+              :core:navigation:allTests
+              :core:network:allTests
+              :core:prefs:allTests
+              :core:repository:allTests
+              :core:service:allTests
+              :core:takserver:allTests
+              :core:testing:allTests
+              :core:ui:allTests
+            kover: >-
+              :core:ble:koverXmlReport
+              :core:common:koverXmlReport
+              :core:data:koverXmlReport
+              :core:database:koverXmlReport
+              :core:domain:koverXmlReport
+              :core:model:koverXmlReport
+              :core:navigation:koverXmlReport
+              :core:network:koverXmlReport
+              :core:prefs:koverXmlReport
+              :core:repository:koverXmlReport
+              :core:service:koverXmlReport
+              :core:takserver:koverXmlReport
+              :core:testing:koverXmlReport
+              :core:ui:koverXmlReport
+          - name: shard-feature
+            tasks: >-
+              :feature:connections:allTests
+              :feature:firmware:allTests
+              :feature:intro:allTests
+              :feature:map:allTests
+              :feature:messaging:allTests
+              :feature:node:allTests
+              :feature:settings:allTests
+            kover: >-
+              :feature:connections:koverXmlReport
+              :feature:firmware:koverXmlReport
+              :feature:intro:koverXmlReport
+              :feature:map:koverXmlReport
+              :feature:messaging:koverXmlReport
+              :feature:node:koverXmlReport
+              :feature:settings:koverXmlReport
+          - name: shard-app
+            tasks: >-
+              :app:testFdroidDebugUnitTest
+              :app:testGoogleDebugUnitTest
+              :desktop:test
+              :core:barcode:testFdroidDebugUnitTest
+              :core:barcode:testGoogleDebugUnitTest
+              :mesh_service_example:test
+            kover: >-
+              :app:koverXmlReportFdroidDebug
+              :app:koverXmlReportGoogleDebug
+              :core:barcode:koverXmlReportFdroidDebug
+              :core:barcode:koverXmlReportGoogleDebug
+              :desktop:koverXmlReport
+              :mesh_service_example:koverXmlReportDebug
 
-      - name: Upload unit test results to Codecov
-        if: ${{ !cancelled() && inputs.run_unit_tests }}
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 1
+          submodules: true
+
+      - name: Gradle Setup
+        uses: ./.github/actions/gradle-setup
+        with:
+          gradle_encryption_key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
+          cache_read_only: ${{ needs.lint-check.outputs.cache_read_only }}
+
+      - name: Run Tests & Coverage (${{ matrix.shard.name }})
+        run: |
+          kover_tasks=""
+          if [[ "${{ inputs.run_coverage }}" == "true" ]]; then
+            kover_tasks="${{ matrix.shard.kover }}"
+          fi
+          ./gradlew ${{ matrix.shard.tasks }} $kover_tasks -Pci=true --continue --scan
+
+      - name: Upload test results to Codecov
+        if: ${{ !cancelled() }}
         uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           slug: meshtastic/Meshtastic-Android
-          flags: host-unit
+          flags: ${{ matrix.shard.name }}
           fail_ci_if_error: false
           report_type: test_results
           files: "**/build/test-results/**/*.xml"
 
-      - name: Upload host reports
+      - name: Upload coverage to Codecov
+        if: ${{ !cancelled() }}
+        uses: codecov/codecov-action@v6
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          slug: meshtastic/Meshtastic-Android
+          flags: ${{ matrix.shard.name }}
+          fail_ci_if_error: false
+          files: "**/build/reports/kover/report*.xml"
+
+      - name: Upload shard reports
         if: ${{ always() && inputs.upload_artifacts }}
         uses: actions/upload-artifact@v7
         with:
-          name: reports-host
+          name: reports-${{ matrix.shard.name }}
           path: |
             **/build/reports
             **/build/test-results
           retention-days: 7
 
+  # ── Android Build & Instrumented Tests ──────────────────────────────
   android-check:
     runs-on: ubuntu-24.04
     permissions:
       contents: read
     timeout-minutes: 60
-    needs: host-check
+    needs: lint-check
+    env:
+      VERSION_CODE: ${{ needs.lint-check.outputs.version_code }}
     strategy:
       fail-fast: true
       matrix:
@@ -145,14 +255,14 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v6
         with:
-          fetch-depth: 0
-          submodules: 'recursive'
+          fetch-depth: 1
+          submodules: true
 
       - name: Gradle Setup
         uses: ./.github/actions/gradle-setup
         with:
           gradle_encryption_key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
-          cache_read_only: ${{ needs.host-check.outputs.cache_read_only }}
+          cache_read_only: ${{ needs.lint-check.outputs.cache_read_only }}
 
       - name: Determine matrix metadata
         id: matrix_meta
@@ -235,7 +345,7 @@ jobs:
       - name: Report App Size
         if: ${{ always() && steps.matrix_meta.outputs.is_first_api == 'true' }}
         run: |
-          echo "### 📦 App Size Report" >> $GITHUB_STEP_SUMMARY
+          echo "### App Size Report" >> $GITHUB_STEP_SUMMARY
           echo "| Artifact | Size |" >> $GITHUB_STEP_SUMMARY
           echo "| --- | --- |" >> $GITHUB_STEP_SUMMARY
           find app/build/outputs/apk -name "*.apk" -exec du -h {} + | awk '{print "| " $2 " | " $1 " |"}' >> $GITHUB_STEP_SUMMARY
@@ -250,26 +360,29 @@ jobs:
           retention-days: 7
           if-no-files-found: ignore
 
+  # ── Desktop Build ───────────────────────────────────────────────────
   build-desktop:
     name: Build Desktop Debug
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
     permissions:
       contents: read
     timeout-minutes: 60
-    needs: host-check
+    needs: lint-check
+    env:
+      VERSION_CODE: ${{ needs.lint-check.outputs.version_code }}
 
     steps:
       - name: Checkout code
         uses: actions/checkout@v6
         with:
-          fetch-depth: 0
-          submodules: 'recursive'
+          fetch-depth: 1
+          submodules: true
 
       - name: Gradle Setup
         uses: ./.github/actions/gradle-setup
         with:
           gradle_encryption_key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
-          cache_read_only: ${{ needs.host-check.outputs.cache_read_only }}
+          cache_read_only: ${{ needs.lint-check.outputs.cache_read_only }}
 
       - name: Build Desktop
         run: ./gradlew :desktop:packageDistributionForCurrentOS -Pci=true --scan