Protect against regression, fixes #33

Verified by executing test on master, and it lights up like a christmas tree.

settings.gradle.kts

@@ -16,6 +16,7 @@ enableFeaturePreviewQuietly("TYPESAFE_PROJECT_ACCESSORS", "Type-safe project acc
 include(":quality")
 include(":common")
 include(":test")
+include(":test:integration")
 include(":test:internal")
 
 listOf("checkstyle", "pmd").forEach {

test/integration/build.gradle.kts

@@ -0,0 +1,13 @@
+plugins {
+	kotlin
+	id("java-gradle-plugin")
+}
+
+dependencies {
+	implementation(projects.plugin)
+	implementation(projects.quality)
+	implementation(projects.test)
+
+	testImplementation(projects.test.internal)
+	testImplementation(testFixtures(projects.plugin.base))
+}

test/integration/src/test/kotlin/net/twisterrob/gradle/PluginIntegrationTest.kt

@@ -0,0 +1,326 @@
+package net.twisterrob.gradle
+
+import net.twisterrob.gradle.test.GradleBuildTestResources
+import net.twisterrob.gradle.test.GradleBuildTestResources.basedOn
+import net.twisterrob.gradle.test.GradleRunnerRule
+import net.twisterrob.gradle.test.GradleRunnerRuleExtension
+import net.twisterrob.gradle.test.assertHasOutputLine
+import net.twisterrob.gradle.test.assertSuccess
+import org.intellij.lang.annotations.Language
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+
+/**
+ * See all `gradlePlugin { plugins { create() { id =` blocks in this project's build.gradle.kts files.
+ */
+@ExtendWith(GradleRunnerRuleExtension::class)
+class PluginIntegrationTest : BaseIntgTest() {
+
+	override lateinit var gradle: GradleRunnerRule
+
+	/**
+	 * This is a meta-test, it's verifying the code in settings.gradle.kts that it's capable of flagging bad behavior.
+	 */
+	@Test
+	fun `eagerly created task is detected`() {
+		gradle.file(settings, "settings.gradle.kts")
+
+		@Language("gradle")
+		val script = """
+			task eagerlyCreated { }
+		""".trimIndent()
+
+		verifySingleTaskCreated(script, ":eagerlyCreated")
+	}
+
+	/**
+	 * This is a meta-test, it's verifying the code in settings.gradle.kts that it's capable of flagging bad behavior.
+	 */
+	@Test
+	fun `created task is detected`() {
+		gradle.file(settings, "settings.gradle.kts")
+
+		@Language("gradle")
+		val script = """
+			tasks.create("eagerlyCreated") { }
+		""".trimIndent()
+
+		verifySingleTaskCreated(script, ":eagerlyCreated")
+	}
+
+	/**
+	 * This is a meta-test, it's verifying the code in settings.gradle.kts that it's capable of flagging bad behavior.
+	 */
+	@Test
+	fun `registered task is not detected`() {
+		gradle.file(settings, "settings.gradle.kts")
+
+		@Language("gradle")
+		val script = """
+			tasks.register("lazilyRegistered") { }
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	/**
+	 * This is a meta-test, it's verifying the code in settings.gradle.kts that it's capable of flagging bad behavior.
+	 */
+	@Test
+	fun `registered task that is materialized is detected`() {
+		gradle.file(settings, "settings.gradle.kts")
+
+		@Language("gradle")
+		val script = """
+			def task = tasks.register("lazilyRegistered") { }
+			task.get()
+		""".trimIndent()
+
+		verifySingleTaskCreated(script, ":lazilyRegistered")
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			// Kotlin: "net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			// Android: "net.twisterrob.android-app", // :plugin
+			// Android: "net.twisterrob.android-library", // :plugin
+			// Android: "net.twisterrob.android-test", // :plugin
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			"net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `empty project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			"net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			// Android: "net.twisterrob.android-app", // :plugin
+			// Android: "net.twisterrob.android-library", // :plugin
+			// Android: "net.twisterrob.android-test", // :plugin
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			"net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `kotlin project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.kotlin)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			// Kotlin: "net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			// Android: "net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `android app project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.android)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "net.twisterrob.android-app"
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			// Kotlin: "net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			// Android: "net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `android library project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.android)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "net.twisterrob.android-library"
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			"net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			// Android: "net.twisterrob.android-app", // :plugin
+			// Android: "net.twisterrob.android-library", // :plugin
+			// Special: "net.twisterrob.android-test", // :plugin
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			// Android: "net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `android kotlin app project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.android)
+		gradle.basedOn(GradleBuildTestResources.kotlin)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "kotlin-android"
+			apply plugin: "net.twisterrob.android-app"
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@ValueSource(
+		strings = [
+			"net.twisterrob.root", // :plugin:base
+			"net.twisterrob.java", // :plugin:languages
+			"net.twisterrob.java-library", // :plugin:languages
+			"net.twisterrob.kotlin", // :plugin:languages
+			"net.twisterrob.vcs", // :plugin:versioning
+			// Android: "net.twisterrob.android-app", // :plugin
+			// Android: "net.twisterrob.android-library", // :plugin
+			// Special: "net.twisterrob.android-test", // :plugin
+			"net.twisterrob.quality", // :quality
+			"net.twisterrob.pmd", // :pmd
+			"net.twisterrob.checkstyle", // :checkstyle
+			// Android: "net.twisterrob.gradle.test", // :test
+		]
+	)
+	fun `android kotlin library project doesn't create tasks when using plugin`(pluginId: String) {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.android)
+		gradle.basedOn(GradleBuildTestResources.kotlin)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "kotlin-android"
+			apply plugin: "net.twisterrob.android-library"
+			apply plugin: "${pluginId}"
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	@Test
+	fun `android kotlin project doesn't create tasks when using all plugins`() {
+		gradle.file(settings, "settings.gradle.kts")
+		gradle.basedOn(GradleBuildTestResources.android)
+		gradle.basedOn(GradleBuildTestResources.kotlin)
+
+		@Language("gradle")
+		val script = """
+			apply plugin: "kotlin-android"
+			apply plugin: "net.twisterrob.android-app" // :plugin
+			// Android: apply plugin: "net.twisterrob.android-library" // :plugin
+			apply plugin: "net.twisterrob.root" // :plugin:base
+			apply plugin: "net.twisterrob.java" // :plugin:languages
+			apply plugin: "net.twisterrob.java-library" // :plugin:languages
+			apply plugin: "net.twisterrob.kotlin" // :plugin:languages
+			apply plugin: "net.twisterrob.vcs" // :plugin:versioning
+			apply plugin: "net.twisterrob.quality" // :quality
+			apply plugin: "net.twisterrob.pmd" // :pmd
+			apply plugin: "net.twisterrob.checkstyle" // :checkstyle
+			// Android: apply plugin: "net.twisterrob.gradle.test" // :test
+		""".trimIndent()
+
+		verifyTasksNotCreated(script)
+	}
+
+	private fun verifyTasksNotCreated(script: String) {
+		val result = gradle.run(script, ":help").build()
+
+		result.assertSuccess(":help")
+	}
+
+	private fun verifySingleTaskCreated(script: String, taskPath: String) {
+		val result = gradle.run(script, ":help").buildAndFail()
+
+		result.assertHasOutputLine("1 tasks created: $taskPath")
+		result.assertHasOutputLine(
+			Regex(
+				"""$taskPath: java\.lang\.Exception: """
+						+ """task '$taskPath' was created before root project '.*' was configured\."""
+			)
+		)
+	}
+
+	companion object {
+		@Language("gradle.kts")
+		val settings: String = """
+			val created: MutableMap<Task, Throwable> = mutableMapOf()
+			gradle.taskGraph.whenReady {
+				created.remove(created.keys.single { it.path == ":help" })
+				if (created.isNotEmpty()) {
+					val traces = created.entries.joinToString("\n") { (task, error) ->
+						"${'$'}{task.path}: ${'$'}{error.stackTraceToString()}"
+					}
+					error("${'$'}{created.size} tasks created: ${'$'}{created.keys.joinToString { it.path }}\n${'$'}{traces}")
+				}
+			}
+			gradle.beforeProject {
+				val project = this
+				project.tasks.configureEach {
+					val task = this
+					// Note: this will execute after whenReady in some cases, but it doesn't matter as no-one will read it.
+					val message =  "${'$'}{task} was created before ${'$'}{project} was configured."
+					created.put(task, Exception(message))
+				}
+			}
+		""".trimIndent()
+	}
+}