diff --git a/libraries/stdlib/jdk7/build.gradle b/libraries/stdlib/jdk7/build.gradle
index 719642eb780..c95f2ed58ee 100644
--- a/libraries/stdlib/jdk7/build.gradle
+++ b/libraries/stdlib/jdk7/build.gradle
@@ -15,12 +15,6 @@ sourceSets {
     }
     test {
         kotlin {
-            srcDir 'test'
-            if(!BuildPropertiesKt.getKotlinBuildProperties(project).inIdeaSync) {
-                srcDir '../jvm/test'
-                srcDir '../common/test'
-                srcDir '../test'
-            }
         }
     }
     noJdk7Test {
@@ -94,20 +88,6 @@ configureFrontendIr(project)
 
 LibrariesCommon.configureJava9Compilation(project, 'kotlin.stdlib.jdk7')
 
-task testJdk6Tests(type: Test) {
-    dependsOn(':kotlin-stdlib:testClasses')
-    group = "verification"
-    def kotlinStdLibTestOutput = project(':kotlin-stdlib').sourceSets.test.output
-    def objectFactory = project.objects
-    doFirst {
-        testClassesDirs = kotlinStdLibTestOutput
-        classpath = objectFactory.fileCollection().from(
-                testClassesDirs,
-                sourceSets.test.compileClasspath
-        )
-    }
-}
-
 task testNoJdk7(type: Test, dependsOn: noJdk7TestClasses) {
     group = "verification"
 
@@ -115,5 +95,5 @@ task testNoJdk7(type: Test, dependsOn: noJdk7TestClasses) {
     classpath = sourceSets.noJdk7Test.runtimeClasspath
 }
 
-check.dependsOn testJdk6Tests, testNoJdk7
+check.dependsOn testNoJdk7
 
diff --git a/libraries/stdlib/jdk8/build.gradle b/libraries/stdlib/jdk8/build.gradle
index 0c999362e71..a297c7cf586 100644
--- a/libraries/stdlib/jdk8/build.gradle
+++ b/libraries/stdlib/jdk8/build.gradle
@@ -19,13 +19,6 @@ sourceSets {
     }
     test {
         kotlin {
-            srcDir 'test'
-            if(!BuildPropertiesKt.getKotlinBuildProperties(project).inIdeaSync) {
-                srcDir '../jvm/test'
-                srcDir '../common/test'
-                srcDir '../test'
-                srcDir '../jdk7/test'
-            }
         }
     }
     java9 {
@@ -89,28 +82,6 @@ configureFrontendIr(project)
 
 LibrariesCommon.configureJava9Compilation(project, 'kotlin.stdlib.jdk8')
 
-task testJdk6Tests(type: Test) { thisTask ->
-    dependsOn(':kotlin-stdlib:testClasses')
-    check.dependsOn(thisTask)
-    group = "verification"
-    def kotlinStdLibTestOutput = project(':kotlin-stdlib').sourceSets.test.output
-    def objectFactory = project.objects
-    doFirst {
-        testClassesDirs = kotlinStdLibTestOutput
-        classpath = objectFactory.fileCollection().from(
-                testClassesDirs,
-                sourceSets.test.compileClasspath
-        )
-    }
-}
-
-[JdkMajorVersion.JDK_9_0, JdkMajorVersion.JDK_10_0, JdkMajorVersion.JDK_11_0].forEach { jvmVersion ->
-    check.dependsOn(tasks.register("jdk${jvmVersion.majorVersion}Test", Test) { thisTask ->
-        group = "verification"
-        thisTask.javaLauncher.set(JvmToolchain.getToolchainLauncherFor(project, jvmVersion))
-    })
-}
-
 tasks.named("compileModuleTestJava", JavaCompile) {
     sourceCompatibility = JavaVersion.VERSION_1_9
     targetCompatibility = JavaVersion.VERSION_1_9
diff --git a/libraries/stdlib/jvm/build.gradle b/libraries/stdlib/jvm/build.gradle
index 39d039285d2..4b5ff5a0556 100644
--- a/libraries/stdlib/jvm/build.gradle
+++ b/libraries/stdlib/jvm/build.gradle
@@ -35,6 +35,8 @@ sourceSets {
     test {
         kotlin {
             srcDir 'test'
+            srcDir '../jdk7/test'
+            srcDir '../jdk8/test'
         }
     }
     longRunningTest {
@@ -77,6 +79,10 @@ dependencies {
     mainJdk8Api sourceSets.mainJdk7.output
 
     testApi project(':kotlin-test:kotlin-test-junit')
+    if (BuildPropertiesKt.getKotlinBuildProperties(project).inIdeaSync) {
+        testCompileOnly sourceSets.mainJdk7.output
+        testCompileOnly sourceSets.mainJdk8.output
+    }
 
     builtins project(':core:builtins')
 }
@@ -176,8 +182,10 @@ compileTestKotlin {
                 "-opt-in=kotlin.RequiresOptIn",
                 "-opt-in=kotlin.ExperimentalUnsignedTypes",
                 "-opt-in=kotlin.ExperimentalStdlibApi",
+                "-opt-in=kotlin.io.path.ExperimentalPathApi",
                 "-opt-in=kotlin.io.encoding.ExperimentalEncodingApi",
                 "-XXLanguage:+RangeUntilOperator",
+                "-Xallow-kotlin-package", // TODO: maybe rename test packages
         ]
         // This is needed for JavaTypeTest; typeOf for non-reified type parameters doesn't work otherwise, for implementation reasons.
         def args = new ArrayList(freeCompilerArgs)
@@ -186,8 +194,11 @@ compileTestKotlin {
     }
 }
 
-test {
-    systemProperty("supportsNamedCapturingGroup", false)
+[JdkMajorVersion.JDK_9_0, JdkMajorVersion.JDK_10_0, JdkMajorVersion.JDK_11_0].forEach { jvmVersion ->
+    check.dependsOn(tasks.register("jdk${jvmVersion.majorVersion}Test", Test) { thisTask ->
+        group = "verification"
+        thisTask.javaLauncher.set(JvmToolchain.getToolchainLauncherFor(project, jvmVersion))
+    })
 }
 
 compileLongRunningTestKotlin {