[Gradle] Add tags count validator for Gradle integration tests

Our current test tasks setup relies on filtering tests by tags. When a
test accidentally has more than one tag, it will never run on CI because
every test task will filter it out.

Validator will check test method tags count and fail the test if they
are more than one.

^KT-59799 In Progress

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/KGPBaseTest.kt

@@ -27,6 +27,7 @@ import java.nio.file.Path
 @Tag("JUnit5")
 @TestInstance(TestInstance.Lifecycle.PER_CLASS)
 @WithMuteInDatabase
+@TagsCountValidator
 @TestDataPath("\$CONTENT_ROOT/resources/testProject")
 @OsCondition
 abstract class KGPBaseTest {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/testbase/tagsValidator.kt

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.gradle.testbase
+
+import org.junit.jupiter.api.extension.*
+import java.lang.reflect.Method
+
+/**
+ * Extension for JUnit 5 tests checking that only one test tag is applied to the test method.
+ *
+ * Just add it to the test class.
+ */
+@Target(AnnotationTarget.CLASS, AnnotationTarget.ANNOTATION_CLASS, AnnotationTarget.FUNCTION)
+@Retention(AnnotationRetention.RUNTIME)
+@ExtendWith(TagsCountValidatorInterceptor::class)
+annotation class TagsCountValidator
+
+class TagsCountValidatorInterceptor : InvocationInterceptor {
+    override fun interceptTestTemplateMethod(
+        invocation: InvocationInterceptor.Invocation<Void>,
+        invocationContext: ReflectiveInvocationContext<Method>,
+        extensionContext: ExtensionContext
+    ) {
+        val testTags = invocationContext.targetClass.classTags().toSet() +
+                invocationContext.executable.annotations.filterTestTags()
+        if (testTags.isEmpty()) {
+            invocation.skip()
+            throw IllegalStateException(
+                """
+                Test method either does not have test tag annotation (for example @JvmGradlePluginTests)
+                or test tag is not known to this validator.
+                """.trimIndent()
+            )
+        } else if (testTags.size > 1) {
+            invocation.skip()
+            throw IllegalStateException(
+                """
+                Test method should not have more then one test tag annotated on method and class combined!
+                Current test has ${testTags.joinToString()} test tags.
+                """.trimIndent()
+            )
+        } else {
+            invocation.proceed()
+        }
+    }
+
+    private fun Class<*>.classTags(): List<Annotation> {
+        return annotations.filterTestTags() + (superclass?.classTags() ?: emptyList())
+    }
+
+    private fun Array<Annotation>.filterTestTags() = filter {
+        it is JvmGradlePluginTests ||
+                it is DaemonsGradlePluginTests ||
+                it is JsGradlePluginTests ||
+                it is NativeGradlePluginTests ||
+                it is MppGradlePluginTests ||
+                it is AndroidGradlePluginTests ||
+                it is OtherGradlePluginTests
+    }
+}