diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/BaseCppTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/BaseCppTest.java
index 2d9579a82..d8c70ca23 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/BaseCppTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/cpp/BaseCppTest.java
@@ -44,6 +44,9 @@ import org.antlr.v4.tool.Grammar;
 import org.antlr.v4.tool.GrammarSemanticsMessage;
 import org.antlr.v4.tool.LexerGrammar;
 import org.antlr.v4.tool.Rule;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 import org.stringtemplate.v4.STGroup;
 import org.stringtemplate.v4.STGroupString;
@@ -89,6 +92,17 @@ public class BaseCppTest implements RuntimeTestSupport {
 	/** Errors found while running antlr */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	private String getPropertyPrefix() {
 		return "antlr-" + getLanguage().toLowerCase();
 	}
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/csharp/BaseCSharpTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/csharp/BaseCSharpTest.java
index a14067ee4..923b34298 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/csharp/BaseCSharpTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/csharp/BaseCSharpTest.java
@@ -121,6 +121,17 @@ public class BaseCSharpTest implements RuntimeTestSupport {
 	 */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	@Override
 	public void testSetUp() throws Exception {
 		if (CREATE_PER_TEST_DIRECTORIES) {
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/dart/BaseDartTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/dart/BaseDartTest.java
index 6ce699ae9..fd4da1cfb 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/dart/BaseDartTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/dart/BaseDartTest.java
@@ -26,6 +26,9 @@ import org.antlr.v4.test.runtime.*;
 import org.antlr.v4.test.runtime.descriptors.LexerExecDescriptors;
 import org.antlr.v4.test.runtime.descriptors.PerformanceDescriptors;
 import org.antlr.v4.tool.*;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 import org.stringtemplate.v4.STGroup;
 import org.stringtemplate.v4.STGroupString;
@@ -126,6 +129,17 @@ public class BaseDartTest implements RuntimeTestSupport {
 
 	private static String cacheDartPackages;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	private String getPropertyPrefix() {
 		return "antlr-dart";
 	}
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/go/BaseGoTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/go/BaseGoTest.java
index f5596db3e..0226d5023 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/go/BaseGoTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/go/BaseGoTest.java
@@ -41,6 +41,9 @@ import org.antlr.v4.tool.Grammar;
 import org.antlr.v4.tool.GrammarSemanticsMessage;
 import org.antlr.v4.tool.LexerGrammar;
 import org.antlr.v4.tool.Rule;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 import org.stringtemplate.v4.STGroup;
 import org.stringtemplate.v4.STGroupString;
@@ -86,6 +89,17 @@ public class BaseGoTest implements RuntimeTestSupport {
 	/** Errors found while running antlr */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	/**
 	 * Copies all files from go runtime to a temporary folder that is inside a valid GOPATH project structure.
 	 */
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/java/BaseJavaTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/java/BaseJavaTest.java
index 765ab9e9f..d142d1df3 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/java/BaseJavaTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/java/BaseJavaTest.java
@@ -42,6 +42,9 @@ import org.antlr.v4.tool.Grammar;
 import org.antlr.v4.tool.GrammarSemanticsMessage;
 import org.antlr.v4.tool.LexerGrammar;
 import org.antlr.v4.tool.Rule;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 import org.stringtemplate.v4.STGroup;
 import org.stringtemplate.v4.STGroupString;
@@ -170,6 +173,17 @@ public class BaseJavaTest implements RuntimeTestSupport {
 	 */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	@Override
 	public void testSetUp() throws Exception {
 //		STGroup.verbose = true;
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/BaseNodeTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/BaseNodeTest.java
index bfe98a21c..65fb05aba 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/BaseNodeTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/javascript/BaseNodeTest.java
@@ -15,6 +15,9 @@ import org.antlr.v4.semantics.SemanticPipeline;
 import org.antlr.v4.test.runtime.*;
 import org.antlr.v4.tool.Grammar;
 import org.antlr.v4.tool.LexerGrammar;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 
 import java.io.File;
@@ -46,6 +49,17 @@ public class BaseNodeTest implements RuntimeTestSupport {
 	/** Errors found while running antlr */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	@Override
 	public void testSetUp() throws Exception {
 		// new output dir for each test
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/php/BasePHPTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/php/BasePHPTest.java
index f164ffec8..89d9d081f 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/php/BasePHPTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/php/BasePHPTest.java
@@ -30,6 +30,9 @@ import org.antlr.v4.test.runtime.RuntimeTestSupport;
 import org.antlr.v4.test.runtime.StreamVacuum;
 import org.antlr.v4.tool.Grammar;
 import org.antlr.v4.tool.LexerGrammar;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 
 import static org.antlr.v4.test.runtime.BaseRuntimeTest.antlrOnString;
@@ -53,6 +56,17 @@ public class BasePHPTest implements RuntimeTestSupport {
 	 */
 	protected StringBuilder antlrToolErrors;
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	private String getPropertyPrefix() {
 		return "antlr-php";
 	}
diff --git a/runtime-testsuite/test/org/antlr/v4/test/runtime/swift/BaseSwiftTest.java b/runtime-testsuite/test/org/antlr/v4/test/runtime/swift/BaseSwiftTest.java
index 7f2158975..2efd08a64 100644
--- a/runtime-testsuite/test/org/antlr/v4/test/runtime/swift/BaseSwiftTest.java
+++ b/runtime-testsuite/test/org/antlr/v4/test/runtime/swift/BaseSwiftTest.java
@@ -11,6 +11,9 @@ import org.antlr.v4.test.runtime.ErrorQueue;
 import org.antlr.v4.test.runtime.RuntimeTestDescriptor;
 import org.antlr.v4.test.runtime.RuntimeTestSupport;
 import org.antlr.v4.test.runtime.StreamVacuum;
+import org.junit.rules.TestRule;
+import org.junit.rules.TestWatcher;
+import org.junit.runner.Description;
 import org.stringtemplate.v4.ST;
 
 import java.io.BufferedReader;
@@ -96,6 +99,17 @@ public class BaseSwiftTest implements RuntimeTestSupport {
 	 */
 	private final Set<String> sourceFiles = new HashSet<>();
 
+	@org.junit.Rule
+	public final TestRule testWatcher = new TestWatcher() {
+
+		@Override
+		protected void succeeded(Description description) {
+			// remove tmpdir if no error.
+			eraseTempDir();
+		}
+
+	};
+
 	@Override
 	public void testSetUp() throws Exception {
 		// new output dir for each test