Merge pull request #20227 from wordpress-mobile/kapt_processing_tests

`:libs:processors` annotation processing unit test

libs/processors/build.gradle

@@ -14,6 +14,8 @@ dependencies {
     kapt "com.google.auto.service:auto-service:$googleAutoServiceVersion"
     implementation "com.squareup:kotlinpoet:$squareupKotlinPoetVersion"
 
+    testImplementation "com.github.tschuchortdev:kotlin-compile-testing:1.5.0"
     testImplementation "junit:junit:$junitVersion"
     testImplementation "org.assertj:assertj-core:$assertjVersion"
+    testImplementation "org.jetbrains.kotlin:kotlin-reflect:$gradle.ext.kotlinVersion"
 }

libs/processors/src/test/kotlin/org/wordpress/android/processor/RemoteConfigProcessorTest.kt

@@ -0,0 +1,151 @@
+package org.wordpress.android.processor
+
+import com.tschuchort.compiletesting.KotlinCompilation
+import com.tschuchort.compiletesting.SourceFile
+import org.assertj.core.api.Assertions.assertThat
+import org.jetbrains.kotlin.utils.addToStdlib.cast
+import org.junit.Test
+
+class RemoteConfigProcessorTest {
+    @Test
+    fun `given a class with features annotation, when compiling, generate expected configuration check`() {
+        // when
+        val result = compile(listOf(featureA))
+
+        // then
+        assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+        assertThat(result.classLoader.loadClass("org.wordpress.android.util.config.RemoteFeatureConfigCheck"))
+            .hasDeclaredMethods("checkRemoteFields")
+    }
+
+    @Test
+    fun `given a class with remote field annotation, when compiling, generate expected config defaults class`() {
+        // given
+        val remoteFieldA = SourceFile.kotlin(
+            "RemoteField.kt", """
+        import org.wordpress.android.annotation.RemoteFieldDefaultGenerater
+        import org.wordpress.android.util.config.AppConfig
+
+        @RemoteFieldDefaultGenerater(remoteField = "remoteField", defaultValue = "default")
+        class RemoteFieldA
+        """
+        )
+
+        // when
+        val result = compile(
+            listOf(
+                remoteFieldA,
+                featureA, /* adding a feature, as without it, annotation processor won't start */
+            )
+        )
+
+        // then
+        assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+        val remoteFieldConfigDefaultsClass =
+            result.classLoader.loadClass("org.wordpress.android.util.config.RemoteFieldConfigDefaults")
+        val remoteFieldConfigDefaultsObject = remoteFieldConfigDefaultsClass.kotlin.objectInstance
+
+        assertThat(
+            remoteFieldConfigDefaultsClass.getDeclaredField("remoteFieldConfigDefaults")
+                .apply { isAccessible = true }
+                .get(remoteFieldConfigDefaultsObject)
+                .cast<Map<String, Any>>()
+        ).containsEntry("remoteField", "default")
+    }
+
+    @Test
+    fun `given class with feature and experiment annotation, when compiling, generate config defaults class`() {
+        // given
+        val experiment = SourceFile.kotlin(
+            "Experiment.kt", """
+        import org.wordpress.android.annotation.Experiment
+        import org.wordpress.android.util.config.AppConfig
+
+        @Experiment("experimentFeature", "defaultVariant")
+        class Experiment
+        """
+        )
+
+        // when
+        val result = compile(listOf(featureA, experiment))
+
+        // then
+        assertThat(result.exitCode).isEqualTo(KotlinCompilation.ExitCode.OK)
+        val remoteFieldConfigDefaultsClass =
+            result.classLoader.loadClass("org.wordpress.android.util.config.RemoteFeatureConfigDefaults")
+        val remoteFieldConfigDefaultsObject = remoteFieldConfigDefaultsClass.kotlin.objectInstance
+
+        assertThat(
+            remoteFieldConfigDefaultsClass.getDeclaredField("remoteFeatureConfigDefaults")
+                .apply { isAccessible = true }
+                .get(remoteFieldConfigDefaultsObject)
+                .cast<Map<String, Any>>()
+        ).containsExactlyInAnyOrderEntriesOf(
+            mapOf(
+                "experimentFeature" to "defaultVariant",
+                "remoteField" to "false"
+            )
+        )
+    }
+
+    @Test
+    fun `given class with feature in development annotation, when compiling, generate expected list of classes`() {
+        // given
+        val experiment = SourceFile.kotlin(
+            "Experiment.kt", """
+        import org.wordpress.android.annotation.FeatureInDevelopment
+        import org.wordpress.android.util.config.AppConfig
+
+        @FeatureInDevelopment
+        class DevFeature
+        """
+        )
+
+        // when
+        val result = compile(
+            listOf(
+                experiment,
+                featureA, /* adding a feature, as without it, annotation processor won't start */
+            )
+        )
+
+        // then
+
+        val featuresInDevelopmentClass =
+            result.classLoader.loadClass("org.wordpress.android.util.config.FeaturesInDevelopment")
+        val featuresInDevelopmentObject = featuresInDevelopmentClass.kotlin.objectInstance
+        assertThat(
+            featuresInDevelopmentClass.getDeclaredField("featuresInDevelopment")
+                .apply { isAccessible = true }
+                .get(featuresInDevelopmentObject)
+                .cast<List<String>>()
+        ).containsOnly("DevFeature")
+    }
+
+    private fun compile(src: List<SourceFile>) = KotlinCompilation().apply {
+        sources = src + fakeAppConfig
+        annotationProcessors = listOf(RemoteConfigProcessor())
+        inheritClassPath = true
+        messageOutputStream = System.out
+    }.compile()
+
+    // Fake AppConfig is needed, as it's a class that is expected to be present in the classpath. Originally, this class
+    // is placed in `WordPress` module.
+    private val fakeAppConfig = SourceFile.kotlin(
+        "AppConfig.kt", """
+        package org.wordpress.android.util.config
+
+        class AppConfig
+    """
+    )
+
+    private val featureA = SourceFile.kotlin(
+        "Feature.kt", """
+        import org.wordpress.android.annotation.Feature
+        import org.wordpress.android.util.config.AppConfig
+
+        @Feature("remoteField", false)
+        class FeatureA(appConfig: AppConfig, val remoteField: String ="foo")
+        """
+    )
+}