Test plugin against multiple versions of Gradle

gradle-plugins/compose/build.gradle.kts

@@ -57,18 +57,29 @@ val jar = tasks.named<Jar>("jar") {
     this.duplicatesStrategy = DuplicatesStrategy.INCLUDE
 }
 
-val gradleVersionForTests = "6.7"
+val minGradleVersionForTests = "6.4"
+val maxGradleVersionForTests = "6.7"
 val java14Home: String? = when (JavaVersion.current()) {
     JavaVersion.VERSION_14 -> System.getProperty("java.home")
     else -> System.getenv("JDK_14")
 }
 val isWindows = getCurrentOperatingSystem().isWindows
 
-afterEvaluate {
+tasks.test {
-    tasks.named<Test>("test") {
+    configureTest(maxGradleVersionForTests)
+}
+
+tasks.register("testMinGradleVersion", Test::class.java) {
+    tasks.test.get().let { defaultTest ->
+        classpath = defaultTest.classpath
+    }
+    configureTest(minGradleVersionForTests)
+}
+
+fun Test.configureTest(gradleVersion: String) {
     dependsOn("publishToMavenLocal")
     systemProperty("compose.plugin.version", BuildProperties.deployVersion(project))
-        systemProperty("gradle.version.for.tests", gradleVersionForTests)
+    systemProperty("gradle.version.for.tests", gradleVersion)
 
     if (java14Home != null) {
         val executableFileName = if (isWindows) "java.exe" else "java"
@@ -77,4 +88,3 @@ afterEvaluate {
         doFirst { error("Use JDK 14 to run tests or set up JDK_14 env. var") }
     }
 }
-}

gradle-plugins/compose/src/test/kotlin/org/jetbrains/compose/test/TestProject.kt

@@ -5,8 +5,7 @@ import java.io.File
 
 data class TestProject(
     private val name: String,
-    private val workingDir: File,
+    private val workingDir: File
-    private val defaultGradleVersion: String = TestProperties.defaultGradleVersionForTests
 ) {
     private val additionalArgs = listOf("--stacktrace")
 
@@ -32,7 +31,7 @@ data class TestProject(
 
     fun gradle(vararg args: String): GradleRunner =
         GradleRunner.create().apply {
-            withGradleVersion(defaultGradleVersion)
+            withGradleVersion(TestProperties.gradleVersionForTests)
             withProjectDir(workingDir)
             withArguments(args.toList() + additionalArgs)
         }

gradle-plugins/compose/src/test/kotlin/org/jetbrains/compose/test/TestProperties.kt

@@ -7,6 +7,6 @@ object TestProperties {
     val composeVersion: String
         get() = System.getProperty("compose.plugin.version")!!
 
-    val defaultGradleVersionForTests: String
+    val gradleVersionForTests: String
         get() = System.getProperty("gradle.version.for.tests")!!
 }