feat: Add Jacoco coverage and report generation

.github/workflows/pr_code_coverage.yaml

@@ -0,0 +1,40 @@
+name: pr_code_coverage
+on:
+    pull_request:
+        branches:
+            - main
+        types: [opened, reopened, synchronize]
+
+jobs:
+    code-coverage:
+        runs-on: ubuntu-latest
+        name: Generate code coverage report
+        permissions:
+            pull-requests: write
+
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v4
+
+            - name: Setup JDK environment
+              uses: actions/setup-java@v4
+              with:
+                  distribution: "zulu"
+                  java-version: 17
+                  cache: 'gradle'
+
+            - name: Generate coverage report
+              run: ./gradlew jacocoCoreDebugCodeCoverage
+
+            - name: Add coverage to PR
+              id: jacoco
+              uses: madrapps/[email protected]
+              with:
+                  paths: |
+                      ${{ github.workspace }}/**/build/reports/jacoco/jacocoCoreDebugCodeCoverage/jacocoCoreDebugCodeCoverage.xml
+                  token: ${{ secrets.GITHUB_TOKEN }}
+                  min-coverage-overall: 40
+                  min-coverage-changed-files: 60
+                  title: Code Coverage
+                  update-comment: true
+                  debug-mode: true

app/build.gradle.kts

@@ -1,4 +1,5 @@
 import java.io.FileInputStream
+import java.util.Locale
 import java.util.Properties
 
 val keystorePropertiesFile = rootProject.file("keystore.properties")
@@ -16,6 +17,11 @@ plugins {
     id("io.gitlab.arturbosch.detekt")
     id("com.google.devtools.ksp") version "2.0.0-1.0.22" apply true
     id("de.mannodermaus.android-junit5") version "1.11.2.0"
+    id("jacoco")
+}
+
+jacoco {
+    toolVersion = "0.8.12"
 }
 
 val kotlinVersion by extra("2.0.0")
@@ -63,6 +69,8 @@ android {
     buildTypes {
         getByName("debug") {
             applicationIdSuffix = ".debug"
+            enableUnitTestCoverage = true
+            enableAndroidTestCoverage = true
         }
         getByName("release") {
             isMinifyEnabled = true
@@ -99,6 +107,46 @@ android {
     }
 
     namespace = "be.scri"
+
+    applicationVariants.all {
+        val variantName = this.name.replaceFirstChar { if (it.isLowerCase()) it.titlecase(Locale.getDefault()) else it.toString() }
+        val unitTests = "test${variantName}UnitTest"
+        val androidTests = "connected${variantName}AndroidTest"
+
+        val exclusions = listOf(
+            // data binding
+            "**/R.class",
+            "**/R\$*.class",
+            "**/BuildConfig.*",
+            "**/Manifest*.*",
+            "**/*Test*.*"
+        )
+
+        tasks.register<JacocoReport>("jacoco${variantName}CodeCoverage") {
+            dependsOn(listOf(unitTests, androidTests))
+            group = "Reporting"
+            description = "Generate Jacoco coverage reports for the $variantName build"
+            reports {
+                xml.required.set(true)
+                html.required.set(true)
+            }
+            // Set source directories to the main source directory
+            sourceDirectories.setFrom(layout.projectDirectory.dir("src/main"))
+            // Set class directories to compiled Java and Kotlin classes, excluding specified exclusions
+            classDirectories.setFrom(files(
+                fileTree(layout.buildDirectory.dir("intermediates/javac/")) {
+                    exclude(exclusions)
+                },
+                fileTree(layout.buildDirectory.dir("tmp/kotlin-classes/")) {
+                    exclude(exclusions)
+                }
+            ))
+            // Collect execution data from .exec and .ec files generated during test execution
+            executionData.setFrom(files(
+                fileTree(layout.buildDirectory) { include(listOf("**/*.exec", "**/*.ec")) }
+            ))
+        }
+    }
 }
 
 dependencies {
@@ -155,3 +203,10 @@ tasks.register<Copy>("moveFromi18n") {
 tasks.named("preBuild").configure {
     dependsOn(tasks.named("moveFromi18n"))
 }
+
+tasks.withType(Test::class) {
+    configure<JacocoTaskExtension> {
+        isIncludeNoLocationClasses = true
+        excludes = listOf("jdk.internal.*")
+    }
+}