Add: Code coverage to the plugin tests (#62)

Author: Rolf-Smit

.github/workflows/build.yml

@@ -16,4 +16,8 @@ jobs:
         uses: reactivecircus/android-emulator-runner@v2
         with:
           api-level: 28
-          script: ./gradlew clean test --stacktrace
+          script: ./gradlew clean test --stacktrace
+      - name: upload coverage
+        uses: codecov/codecov-action@v2
+        with:
+          files: ./plugin/build/reports/jacoco/test/jacocoTestReport.xml

README.md

@@ -1,6 +1,7 @@
 [![Gradle Plugin Portal](https://img.shields.io/maven-metadata/v/https/plugins.gradle.org/m2/nl.neotech.plugin/android-root-coverage-plugin/maven-metadata.xml.svg?label=Gradle%20Plugin%20Portal)](https://plugins.gradle.org/plugin/nl.neotech.plugin.rootcoverage)
 [![Maven Central](https://img.shields.io/maven-central/v/nl.neotech.plugin/android-root-coverage-plugin?label=Maven%20Central)](https://search.maven.org/artifact/nl.neotech.plugin/android-root-coverage-plugin)
 [![Build](https://github.com/NeoTech-Software/Android-Root-Coverage-Plugin/actions/workflows/build.yml/badge.svg?branch=master)](https://github.com/NeoTech-Software/Android-Root-Coverage-Plugin/actions/workflows/build.yml)
+[![Coverage](https://img.shields.io/codecov/c/gh/NeoTech-Software/Android-Root-Coverage-Plugin/branch/master?token=4I3MXF2WLX)](https://app.codecov.io/gh/NeoTech-Software/Android-Root-Coverage-Plugin/branch/master)
 
 # Android-Root-Coverage-Plugin
 **Automatically configures Jacoco code coverage tasks for both combined and per module coverage reports.**

plugin/build.gradle

@@ -1,6 +1,7 @@
 plugins {
     // Core Gradle plugins
     id "java-gradle-plugin"
+    id "jacoco"
 
     // Third-party plugins
     alias(libs.plugins.kotlinJvm)
@@ -23,6 +24,13 @@ java {
     targetCompatibility = JavaVersion.VERSION_1_8
 }
 
+jacocoTestReport {
+    reports {
+        xml.required = true
+        csv.required = false
+    }
+}
+
 plugins.withId("com.vanniktech.maven.publish") {
     mavenPublish {
         sonatypeHost = "S01"
@@ -76,3 +84,47 @@ dependencies {
     testImplementation gradleTestKit()
     testImplementation libs.mockk
 }
+
+// Setup Jacoco for Gradle TestKit
+pluginManager.withPlugin("jacoco") {
+
+    // Extracts the JaCoCo runtime jar from the configured JaCoCo Agent
+    def extractJacocoRuntimeTask = tasks.register("extractJacocoTestKitRuntime", Copy) {
+        from {
+            zipTree(project.configurations.getByName(JacocoPlugin.AGENT_CONFIGURATION_NAME).asPath).matching { include 'jacocoagent.jar' }.singleFile
+        }
+        into file("${buildDir}/testkit")
+    }
+
+    def javaTestTask = tasks.named(JavaPlugin.TEST_TASK_NAME)
+
+    def destinationFileProvider = javaTestTask.map {
+        (it.extensions.getByType(JacocoTaskExtension.class) as JacocoTaskExtension).destinationFile
+    }
+
+    // Generates a gradle.properties file that contains the correct JVM arguments to run with the extracted JaCoCo agent
+    def generateGradlePropertiesTask = tasks.register("generateJacocoTestKitGradleProperties", WriteProperties.class) {
+        it.group = "reporting"
+        it.description = "Generates testkit-gradle.properties file which can be read and added to a TestKit build as gradle.properties"
+        it.dependsOn(extractJacocoRuntimeTask)
+        it.outputFile = new File(buildDir, "testkit/${javaTestTask.name}/gradle.properties")
+        it.property("org.gradle.jvmargs", "\"-javaagent:${buildDir}/testkit/jacocoagent.jar=destfile=${destinationFileProvider.get()}\"")
+    }
+
+    // Make the generated gradle.properties file available on the test classpath as resource
+    dependencies.add(JavaPlugin.TEST_RUNTIME_ONLY_CONFIGURATION_NAME, files(new File(buildDir, "testkit/${javaTestTask.name}")))
+
+    // "Fixes": https://github.com/gradle/gradle/issues/16603
+    def jacocoTestReport = tasks.named("jacocoTestReport")
+    jacocoTestReport.configure {
+        it.doFirst {
+            sleep(1000)
+        }
+    }
+
+    // Setup task dependencies
+    javaTestTask.configure {
+        it.dependsOn(generateGradlePropertiesTask)
+        it.finalizedBy(jacocoTestReport)
+    }
+}

plugin/src/test/kotlin/org/neotech/plugin/rootcoverage/IntegrationTest.kt

@@ -10,6 +10,7 @@ import org.junit.runners.Parameterized
 import org.neotech.plugin.rootcoverage.util.SystemOutputWriter
 import org.neotech.plugin.rootcoverage.util.createGradlePropertiesFile
 import org.neotech.plugin.rootcoverage.util.createLocalPropertiesFile
+import org.neotech.plugin.rootcoverage.util.put
 import java.io.File
 import java.util.Properties
 import kotlin.test.assertEquals
@@ -27,6 +28,10 @@ class IntegrationTest(
         createLocalPropertiesFile(projectRoot)
         createGradlePropertiesFile(projectRoot, properties = Properties().apply {
             put("android.useAndroidX", "true")
+            put(Properties().apply {
+                val resource = GradleRunner::class.java.classLoader.getResourceAsStream("gradle.properties")
+                load(resource)
+            })
         })
 
         val runner = GradleRunner.create()

plugin/src/test/kotlin/org/neotech/plugin/rootcoverage/util/ProjectGeneration.kt

@@ -20,6 +20,18 @@ internal fun createGradlePropertiesFile(root: File, properties: Properties) {
     File(root, "gradle.properties").outputStream().use { properties.store(it, null) }
 }
 
+internal fun Properties.put(properties: Properties) {
+    properties.forEach {
+        put(it.key, it.value)
+    }
+}
+
+internal fun File.getProperties(): Properties = inputStream().use {
+        Properties().apply {
+            load(it)
+        }
+    }
+
 /**
  * Tries to resolve the Android SDK directory. This function first tries the ANDROID_HOME system
  * environment variable if this variable does not exist it tries to find and parse the