Manually include Kotlin class folders (#82)

* Extend KotlinDirectoryProvider to construct folders manually, if the Kotlin plugin is applied after JUnit 5

Author: Marcel Schnelle

android-junit5-tests/src/test/groovy/de/mannodermaus/gradle/plugins/junit5/FunctionalSpec.groovy

@@ -192,8 +192,8 @@ class FunctionalSpec extends Specification {
   def "Executes Kotlin tests in flavor-specific source set"() {
     given:
     androidPlugin(flavorNames: ["free"])
-    kotlinPlugin()
     junit5Plugin()
+    kotlinPlugin()
     javaFile()
     kotlinTest()
     kotlinTest("free", null)

android-junit5-tests/src/test/kotlin/de/mannodermaus/gradle/plugins/junit5/PluginSpec.kt

@@ -6,8 +6,11 @@ import de.mannodermaus.gradle.plugins.junit5.internal.ConfigurationKind.ANDROID_
 import de.mannodermaus.gradle.plugins.junit5.internal.ConfigurationScope.RUNTIME_ONLY
 import de.mannodermaus.gradle.plugins.junit5.internal.android
 import de.mannodermaus.gradle.plugins.junit5.internal.find
+import de.mannodermaus.gradle.plugins.junit5.providers.JavaDirectoryProvider
+import de.mannodermaus.gradle.plugins.junit5.providers.KotlinDirectoryProvider
 import de.mannodermaus.gradle.plugins.junit5.tasks.AndroidJUnit5JacocoReport
 import de.mannodermaus.gradle.plugins.junit5.tasks.AndroidJUnit5UnitTest
+import de.mannodermaus.gradle.plugins.junit5.util.TaskUtils.argument
 import de.mannodermaus.gradle.plugins.junit5.util.TestEnvironment
 import de.mannodermaus.gradle.plugins.junit5.util.TestProjectFactory
 import de.mannodermaus.gradle.plugins.junit5.util.TestProjectFactory.TestProjectBuilder
@@ -505,6 +508,35 @@ class PluginSpec : Spek({
         }
       }
 
+      context("test folder detection") {
+        // The order of applying the Kotlin plugin shouldn't interfere
+        // with the detection of its source directories
+        // (https://github.com/mannodermaus/android-junit5/issues/72)
+        beforeEachTest { testProjectBuilder.applyKotlinPlugin() }
+
+        listOf("debug", "release").forEach { buildType ->
+
+          on("assembling the $buildType task") {
+            val project = testProjectBuilder.buildAndEvaluate()
+            val projectConfig = ProjectConfig(project)
+            val task = project.tasks.get<AndroidJUnit5UnitTest>("junitPlatformTest${buildType.capitalize()}")
+            val folders = argument(task, "--scan-class-path")?.split(":") ?: listOf()
+
+            val variant = projectConfig.unitTestVariants.find { it.name == buildType }
+            require(variant != null)
+
+            listOf(
+                JavaDirectoryProvider(variant!!),
+                KotlinDirectoryProvider(project, variant)).forEach { provider ->
+
+              it("contains all class folders of the ${provider.javaClass.simpleName}") {
+                assertThat(folders).containsAll(provider.classDirectories().map { it.absolutePath })
+              }
+            }
+          }
+        }
+      }
+
       context("jacoco integration") {
         beforeEachTest { testProjectBuilder.applyJacocoPlugin() }
 

android-junit5/src/main/kotlin/de/mannodermaus/gradle/plugins/junit5/providers/Kotlin.kt

@@ -2,10 +2,12 @@ package de.mannodermaus.gradle.plugins.junit5.providers
 
 import com.android.build.gradle.api.BaseVariant
 import com.android.builder.model.SourceProvider
+import de.mannodermaus.gradle.plugins.junit5.internal.agpLog
 import de.mannodermaus.gradle.plugins.junit5.internal.unitTestVariant
 import org.gradle.api.Project
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.api.internal.HasConvention
+import org.gradle.api.logging.LogLevel.WARN
 import org.jetbrains.kotlin.gradle.plugin.KOTLIN_DSL_NAME
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
@@ -34,8 +36,16 @@ class KotlinDirectoryProvider(
           .toSet()
 
   private fun classFoldersOf(variant: BaseVariant): Set<File> {
-    val kotlinTask = project.tasks.findByName(variant.kotlinTaskName) ?: return emptySet()
-    return setOf((kotlinTask as KotlinCompile).destinationDir)
+    val kotlinTask = project.tasks.findByName(variant.kotlinTaskName)
+    return if (kotlinTask != null) {
+      // Read folder directly from the Kotlin task
+      setOf((kotlinTask as KotlinCompile).destinationDir)
+    } else {
+      // If the Kotlin plugin is applied _after_ JUnit 5 in the build file,
+      // fall back to the expected path… However, make sure to log a warning to users!
+      project.logger.agpLog(WARN, "The kotlin-android plugin is currently applied after android-junit5! To guarantee full compatibility, please declare it above the JUnit 5 plugin.")
+      setOf(File(project.buildDir, "tmp/kotlin-classes/${variant.name}"))
+    }
   }
 }