diff --git a/tools/deobfuscator-js/build.gradle.kts b/tools/deobfuscator-js/build.gradle.kts
index 11acb0b4c..f681ba8bb 100644
--- a/tools/deobfuscator-js/build.gradle.kts
+++ b/tools/deobfuscator-js/build.gradle.kts
@@ -56,7 +56,7 @@ val generateLibJs by tasks.register<JavaExec>("generateLibJs") {
     mainClass.set("org.teavm.tooling.deobfuscate.js.Compiler")
     args(
         "org.teavm.tooling.deobfuscate.js.DeobfuscatorLib",
-        "\$teavm_deobfuscator",
+        "deobfuscator",
         File(buildDir, "teavm-lib").absolutePath,
         "deobfuscator-lib.js",
     )
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtensionImpl.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtensionImpl.java
index 6282c3b40..28c3114d9 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtensionImpl.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtensionImpl.java
@@ -21,17 +21,23 @@ import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Properties;
 import javax.inject.Inject;
+import org.gradle.api.Action;
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.Dependency;
+import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.provider.Provider;
+import org.teavm.gradle.api.TeaVMBaseExtension;
+import org.teavm.gradle.api.TeaVMLibraries;
+import org.teavm.gradle.api.TeaVMTests;
 import org.teavm.gradle.config.ArtifactCoordinates;
 
-public class TeaVMBaseExtensionImpl implements TeaVMBaseExtension {
+class TeaVMBaseExtensionImpl implements TeaVMBaseExtension {
     protected Project project;
     private Provider<Properties> properties;
+    private TeaVMTestsImpl tests;
 
     @Inject
-    public TeaVMBaseExtensionImpl(Project project) {
+    TeaVMBaseExtensionImpl(Project project, ObjectFactory objectFactory) {
         this.project = project;
         properties = project.provider(() -> {
             var result = new Properties();
@@ -44,6 +50,8 @@ public class TeaVMBaseExtensionImpl implements TeaVMBaseExtension {
             }
             return result;
         });
+        tests = new TeaVMTestsImpl(objectFactory);
+        tests.configure(this);
     }
 
     private void append(Properties target, File source) throws IOException {
@@ -102,4 +110,14 @@ public class TeaVMBaseExtensionImpl implements TeaVMBaseExtension {
             return project.getProviders().gradleProperty("teavm." + name).getOrElse(null);
         });
     }
+
+    @Override
+    public TeaVMTests getTests() {
+        return tests;
+    }
+
+    @Override
+    public void tests(Action<TeaVMTests> config) {
+        config.execute(tests);
+    }
 }
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtensionImpl.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtensionImpl.java
index 84e8ce605..f2eacb3e7 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtensionImpl.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtensionImpl.java
@@ -16,21 +16,26 @@
 package org.teavm.gradle;
 
 import java.io.File;
-import javax.inject.Inject;
 import org.gradle.api.Action;
 import org.gradle.api.Project;
 import org.gradle.api.model.ObjectFactory;
+import org.teavm.gradle.api.OptimizationLevel;
+import org.teavm.gradle.api.TeaVMCConfiguration;
+import org.teavm.gradle.api.TeaVMCommonConfiguration;
+import org.teavm.gradle.api.TeaVMExtension;
+import org.teavm.gradle.api.TeaVMJSConfiguration;
+import org.teavm.gradle.api.TeaVMWasiConfiguration;
+import org.teavm.gradle.api.TeaVMWasmConfiguration;
 
-public class TeaVMExtensionImpl extends TeaVMBaseExtensionImpl implements TeaVMExtension {
+class TeaVMExtensionImpl extends TeaVMBaseExtensionImpl implements TeaVMExtension {
     private TeaVMJSConfiguration js;
     private TeaVMWasmConfiguration wasm;
     private TeaVMWasiConfiguration wasi;
     private TeaVMCConfiguration c;
     private TeaVMCommonConfiguration all;
 
-    @Inject
-    public TeaVMExtensionImpl(Project project, ObjectFactory objectFactory) {
-        super(project);
+    TeaVMExtensionImpl(Project project, ObjectFactory objectFactory) {
+        super(project, objectFactory);
         js = objectFactory.newInstance(TeaVMJSConfiguration.class);
         wasm = objectFactory.newInstance(TeaVMWasmConfiguration.class);
         wasi = objectFactory.newInstance(TeaVMWasiConfiguration.class);
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSTestsImpl.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSTestsImpl.java
new file mode 100644
index 000000000..26c984df8
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSTestsImpl.java
@@ -0,0 +1,55 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle;
+
+import org.gradle.api.model.ObjectFactory;
+import org.gradle.api.provider.Property;
+import org.teavm.gradle.api.TeaVMJSTests;
+import org.teavm.gradle.api.TeaVMWebTestRunner;
+
+class TeaVMJSTestsImpl implements TeaVMJSTests {
+    private Property<Boolean> enabled;
+    private Property<TeaVMWebTestRunner> runner;
+    private Property<Boolean> decodeStack;
+
+    TeaVMJSTestsImpl(ObjectFactory objectFactory) {
+        enabled = objectFactory.property(Boolean.class);
+        runner = objectFactory.property(TeaVMWebTestRunner.class);
+        decodeStack = objectFactory.property(Boolean.class);
+    }
+
+    @Override
+    public Property<Boolean> getEnabled() {
+        return enabled;
+    }
+
+    @Override
+    public Property<TeaVMWebTestRunner> getRunner() {
+        return runner;
+    }
+
+    @Override
+    public Property<Boolean> getDecodeStack() {
+        return decodeStack;
+    }
+
+    void configure(TeaVMBaseExtensionImpl extension) {
+        enabled.convention(extension.property("tests.js.enabled").map(Boolean::parseBoolean).orElse(false));
+        runner.convention(extension.property("tests.js.runner").map(s -> TeaVMWebTestRunner.valueOf(s.toUpperCase()))
+                .orElse(TeaVMWebTestRunner.CHROME));
+        decodeStack.convention(extension.property("tests.js.decodeStack").map(Boolean::parseBoolean).orElse(true));
+    }
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraryPlugin.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraryPlugin.java
index 14f173992..4f40b9ab2 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraryPlugin.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraryPlugin.java
@@ -20,6 +20,7 @@ import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.model.ObjectFactory;
 import org.gradle.api.plugins.JavaPlugin;
+import org.teavm.gradle.api.TeaVMBaseExtension;
 import org.teavm.gradle.config.ArtifactCoordinates;
 
 public class TeaVMLibraryPlugin implements Plugin<Project> {
@@ -32,9 +33,10 @@ public class TeaVMLibraryPlugin implements Plugin<Project> {
 
     @Override
     public void apply(Project project) {
-        var extension = objectFactory.newInstance(TeaVMBaseExtensionImpl.class);
+        var extension = new TeaVMBaseExtensionImpl(project, objectFactory);
         project.getExtensions().add(TeaVMBaseExtension.class, TeaVMPlugin.EXTENSION_NAME, extension);
         project.getDependencies().add(JavaPlugin.TEST_IMPLEMENTATION_CONFIGURATION_NAME, ArtifactCoordinates.JUNIT);
-        project.getDependencies().add(JavaPlugin.TEST_IMPLEMENTATION_CONFIGURATION_NAME, ArtifactCoordinates.CLASSLIB);
+        project.getDependencies().add(JavaPlugin.TEST_RUNTIME_ONLY_CONFIGURATION_NAME, ArtifactCoordinates.CLASSLIB);
+        TeaVMTestConfigurator.configure(project, extension.getTests());
     }
 }
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMPlugin.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMPlugin.java
index e78a528b4..15d443fc9 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMPlugin.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMPlugin.java
@@ -27,7 +27,14 @@ import org.gradle.api.plugins.WarPlugin;
 import org.gradle.api.tasks.SourceSet;
 import org.gradle.api.tasks.SourceSetContainer;
 import org.gradle.api.tasks.bundling.War;
+import org.teavm.gradle.api.TeaVMConfiguration;
+import org.teavm.gradle.api.TeaVMExtension;
 import org.teavm.gradle.config.ArtifactCoordinates;
+import org.teavm.gradle.tasks.GenerateCTask;
+import org.teavm.gradle.tasks.GenerateJavaScriptTask;
+import org.teavm.gradle.tasks.GenerateWasiTask;
+import org.teavm.gradle.tasks.GenerateWasmTask;
+import org.teavm.gradle.tasks.TeaVMTask;
 
 public class TeaVMPlugin implements Plugin<Project> {
     public static final String EXTENSION_NAME = "teavm";
@@ -53,10 +60,11 @@ public class TeaVMPlugin implements Plugin<Project> {
         registerTasks(project);
         addDependencies(project);
         setupWarTask(project);
+        TeaVMTestConfigurator.configure(project, project.getExtensions().getByType(TeaVMExtension.class).getTests());
     }
 
     private void registerExtension(Project project) {
-        var extension = objectFactory.newInstance(TeaVMExtensionImpl.class);
+        var extension = new TeaVMExtensionImpl(project, objectFactory);
         project.getExtensions().add(TeaVMExtension.class, EXTENSION_NAME, extension);
     }
 
@@ -83,6 +91,7 @@ public class TeaVMPlugin implements Plugin<Project> {
         sourceSet.setCompileClasspath(sourceSet.getCompileClasspath().plus(main)
                 .plus(project.getConfigurations().getByName(JavaPlugin.COMPILE_CLASSPATH_CONFIGURATION_NAME)));
         sourceSet.java(java -> { });
+        project.getDependencies().add(JavaPlugin.TEST_IMPLEMENTATION_CONFIGURATION_NAME, sourceSet.getOutput());
     }
 
     private void registerTasks(Project project) {
@@ -145,6 +154,7 @@ public class TeaVMPlugin implements Plugin<Project> {
     private void addDependencies(Project project) {
         project.getDependencies().add(CONFIGURATION_NAME, ArtifactCoordinates.CLASSLIB);
         project.getDependencies().add(JavaPlugin.TEST_IMPLEMENTATION_CONFIGURATION_NAME, ArtifactCoordinates.JUNIT);
+        project.getDependencies().add(JavaPlugin.TEST_RUNTIME_ONLY_CONFIGURATION_NAME, ArtifactCoordinates.CLASSLIB);
     }
 
     private void setupWarTask(Project project) {
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestConfigurator.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestConfigurator.java
new file mode 100644
index 000000000..30eb82e0b
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestConfigurator.java
@@ -0,0 +1,60 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle;
+
+import java.io.File;
+import org.gradle.api.Project;
+import org.gradle.api.tasks.testing.Test;
+import org.teavm.gradle.api.TeaVMTests;
+import org.teavm.gradle.api.TeaVMWebTestRunner;
+
+class TeaVMTestConfigurator {
+    private TeaVMTestConfigurator() {
+    }
+
+    static void configure(Project project, TeaVMTests tests) {
+        project.getTasks().withType(Test.class).configureEach(test -> {
+            test.getSystemProperties().putIfAbsent("teavm.junit.target",
+                    new File(project.getBuildDir(), "tests/teavm"));
+            test.getSystemProperties().putIfAbsent("teavm.junit.threads", "1");
+
+            test.getSystemProperties().putIfAbsent("teavm.junit.js.enabled",
+                    tests.getJs().getEnabled().get());
+            test.getSystemProperties().putIfAbsent("teavm.junit.js.runner",
+                    tests.getJs().getRunner().map(TeaVMTestConfigurator::runnerToString).get());
+            test.getSystemProperties().putIfAbsent("teavm.junit.js.decodeStack",
+                    tests.getJs().getDecodeStack().get());
+
+            test.getSystemProperties().putIfAbsent("teavm.junit.wasm.enabled",
+                    tests.getWasm().getEnabled().get());
+            test.getSystemProperties().putIfAbsent("teavm.junit.wasm.runner",
+                    tests.getWasm().getRunner().map(TeaVMTestConfigurator::runnerToString).get());
+        });
+    }
+
+    private static String runnerToString(TeaVMWebTestRunner runner) {
+        switch (runner) {
+            case CHROME:
+                return "browser-chrome";
+            case FIREFOX:
+                return "browser-firefox";
+            case CUSTOM_BROWSER:
+                return "browser";
+            default:
+                return "none";
+        }
+    }
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestsImpl.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestsImpl.java
new file mode 100644
index 000000000..13a02f18b
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTestsImpl.java
@@ -0,0 +1,57 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle;
+
+import org.gradle.api.Action;
+import org.gradle.api.model.ObjectFactory;
+import org.teavm.gradle.api.TeaVMJSTests;
+import org.teavm.gradle.api.TeaVMTests;
+import org.teavm.gradle.api.TeaVMWasmTests;
+
+class TeaVMTestsImpl implements TeaVMTests {
+    private TeaVMJSTestsImpl js;
+    private TeaVMWasmTestsImpl wasm;
+
+    TeaVMTestsImpl(ObjectFactory objectFactory) {
+        js = new TeaVMJSTestsImpl(objectFactory);
+        wasm = new TeaVMWasmTestsImpl(objectFactory);
+    }
+
+    @Override
+    public TeaVMJSTests getJs() {
+        return js;
+    }
+
+    @Override
+    public void js(Action<TeaVMJSTests> config) {
+        config.execute(js);
+    }
+
+    @Override
+    public TeaVMWasmTests getWasm() {
+        return wasm;
+    }
+
+    @Override
+    public void wasm(Action<TeaVMWasmTests> config) {
+        config.execute(wasm);
+    }
+
+    void configure(TeaVMBaseExtensionImpl extension) {
+        js.configure(extension);
+        wasm.configure(extension);
+    }
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmTestsImpl.java b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmTestsImpl.java
new file mode 100644
index 000000000..a8134bff3
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmTestsImpl.java
@@ -0,0 +1,47 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle;
+
+import org.gradle.api.model.ObjectFactory;
+import org.gradle.api.provider.Property;
+import org.teavm.gradle.api.TeaVMWasmTests;
+import org.teavm.gradle.api.TeaVMWebTestRunner;
+
+class TeaVMWasmTestsImpl implements TeaVMWasmTests {
+    private Property<Boolean> enabled;
+    private Property<TeaVMWebTestRunner> runner;
+
+    TeaVMWasmTestsImpl(ObjectFactory objectFactory) {
+        enabled = objectFactory.property(Boolean.class);
+        runner = objectFactory.property(TeaVMWebTestRunner.class);
+    }
+
+    @Override
+    public Property<Boolean> getEnabled() {
+        return enabled;
+    }
+
+    @Override
+    public Property<TeaVMWebTestRunner> getRunner() {
+        return runner;
+    }
+
+    void configure(TeaVMBaseExtensionImpl extension) {
+        enabled.convention(extension.property("tests.wasm.enabled").map(Boolean::parseBoolean).orElse(false));
+        runner.convention(extension.property("tests.wasm.runner").map(s -> TeaVMWebTestRunner.valueOf(s.toUpperCase()))
+                .orElse(TeaVMWebTestRunner.CHROME));
+    }
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/OptimizationLevel.java b/tools/gradle/src/main/java/org/teavm/gradle/api/OptimizationLevel.java
similarity index 95%
rename from tools/gradle/src/main/java/org/teavm/gradle/OptimizationLevel.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/OptimizationLevel.java
index 480e11d9c..d92e732c0 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/OptimizationLevel.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/OptimizationLevel.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 public enum OptimizationLevel {
     NONE,
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtension.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMBaseExtension.java
similarity index 85%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtension.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMBaseExtension.java
index c1d54b21b..158250236 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMBaseExtension.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMBaseExtension.java
@@ -13,12 +13,17 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
+import org.gradle.api.Action;
 import org.gradle.api.provider.Provider;
 
 public interface TeaVMBaseExtension {
     TeaVMLibraries getLibs();
 
     Provider<String> property(String name);
+
+    TeaVMTests getTests();
+
+    void tests(Action<TeaVMTests> config);
 }
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMCConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMCConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCConfiguration.java
index 2f7c13cdd..119a86e0d 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMCConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMCommonConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCommonConfiguration.java
similarity index 97%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMCommonConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCommonConfiguration.java
index 787f374c4..9316f03d8 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMCommonConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMCommonConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import java.io.File;
 import org.gradle.api.provider.ListProperty;
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMConfiguration.java
index 2434c49a0..477f7a1c1 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtension.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMExtension.java
similarity index 97%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtension.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMExtension.java
index 3a9aef486..ca6732c50 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMExtension.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMExtension.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.Action;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSConfiguration.java
index 021fa0fdc..b33695eab 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMJSConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSTests.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSTests.java
new file mode 100644
index 000000000..20ffacccf
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMJSTests.java
@@ -0,0 +1,26 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle.api;
+
+import org.gradle.api.provider.Property;
+
+public interface TeaVMJSTests {
+    Property<Boolean> getEnabled();
+
+    Property<TeaVMWebTestRunner> getRunner();
+
+    Property<Boolean> getDecodeStack();
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraries.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMLibraries.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraries.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMLibraries.java
index 2dc31139a..4a2ad5c90 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMLibraries.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMLibraries.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.artifacts.Dependency;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMNativeBaseConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMNativeBaseConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMNativeBaseConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMNativeBaseConfiguration.java
index ce439b334..d915c013e 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMNativeBaseConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMNativeBaseConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMTests.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMTests.java
new file mode 100644
index 000000000..48a042cb1
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMTests.java
@@ -0,0 +1,28 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle.api;
+
+import org.gradle.api.Action;
+
+public interface TeaVMTests {
+    TeaVMJSTests getJs();
+
+    void js(Action<TeaVMJSTests> config);
+
+    TeaVMWasmTests getWasm();
+
+    void wasm(Action<TeaVMWasmTests> config);
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasiConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasiConfiguration.java
similarity index 95%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasiConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasiConfiguration.java
index a5d7203e4..f1e208359 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasiConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasiConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 public interface TeaVMWasiConfiguration extends TeaVMWasmBaseConfiguration, TeaVMConfiguration {
 }
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmBaseConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmBaseConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmBaseConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmBaseConfiguration.java
index 62cbac84d..f7bfdb559 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmBaseConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmBaseConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmConfiguration.java
similarity index 95%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmConfiguration.java
index d53af9cca..fd1a9392b 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWasmConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 public interface TeaVMWasmConfiguration extends TeaVMWebConfiguration, TeaVMWasmBaseConfiguration {
 }
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmTests.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmTests.java
new file mode 100644
index 000000000..6be07b69c
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWasmTests.java
@@ -0,0 +1,24 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle.api;
+
+import org.gradle.api.provider.Property;
+
+public interface TeaVMWasmTests {
+    Property<Boolean> getEnabled();
+
+    Property<TeaVMWebTestRunner> getRunner();
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWebConfiguration.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebConfiguration.java
similarity index 96%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMWebConfiguration.java
rename to tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebConfiguration.java
index 436a2af2b..da9ca073a 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMWebConfiguration.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebConfiguration.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.api;
 
 import org.gradle.api.provider.Property;
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebTestRunner.java b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebTestRunner.java
new file mode 100644
index 000000000..70414874d
--- /dev/null
+++ b/tools/gradle/src/main/java/org/teavm/gradle/api/TeaVMWebTestRunner.java
@@ -0,0 +1,23 @@
+/*
+ *  Copyright 2023 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.gradle.api;
+
+public enum TeaVMWebTestRunner {
+    CUSTOM_BROWSER,
+    CHROME,
+    FIREFOX,
+    NONE
+}
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/GenerateCTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateCTask.java
similarity index 98%
rename from tools/gradle/src/main/java/org/teavm/gradle/GenerateCTask.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateCTask.java
index cde3fc95f..2eab7fb38 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/GenerateCTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateCTask.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import org.gradle.api.provider.Property;
 import org.gradle.api.tasks.Input;
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/GenerateJavaScriptTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateJavaScriptTask.java
similarity index 98%
rename from tools/gradle/src/main/java/org/teavm/gradle/GenerateJavaScriptTask.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateJavaScriptTask.java
index 1131193e1..2b0d005d8 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/GenerateJavaScriptTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateJavaScriptTask.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import org.gradle.api.provider.Property;
 import org.gradle.api.tasks.Input;
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/GenerateWasiTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasiTask.java
similarity index 97%
rename from tools/gradle/src/main/java/org/teavm/gradle/GenerateWasiTask.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasiTask.java
index b18934b84..c877d844a 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/GenerateWasiTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasiTask.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import org.gradle.api.provider.Property;
 import org.gradle.api.tasks.Input;
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/GenerateWasmTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmTask.java
similarity index 97%
rename from tools/gradle/src/main/java/org/teavm/gradle/GenerateWasmTask.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmTask.java
index cdf38d187..e783bd314 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/GenerateWasmTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GenerateWasmTask.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import org.gradle.api.provider.Property;
 import org.gradle.api.tasks.Input;
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/GradleTeaVMToolLog.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GradleTeaVMToolLog.java
similarity index 89%
rename from tools/gradle/src/main/java/org/teavm/gradle/GradleTeaVMToolLog.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/GradleTeaVMToolLog.java
index 7611c9e66..2a7c4aa1d 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/GradleTeaVMToolLog.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/GradleTeaVMToolLog.java
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2015 Alexey Andreev.
+ *  Copyright 2023 Alexey Andreev.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -13,15 +13,15 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import org.gradle.api.logging.Logger;
 import org.teavm.tooling.TeaVMToolLog;
 
-public class GradleTeaVMToolLog implements TeaVMToolLog {
+class GradleTeaVMToolLog implements TeaVMToolLog {
     private Logger log;
 
-    public GradleTeaVMToolLog(Logger log) {
+    GradleTeaVMToolLog(Logger log) {
         this.log = log;
     }
 
diff --git a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTask.java b/tools/gradle/src/main/java/org/teavm/gradle/tasks/TeaVMTask.java
similarity index 98%
rename from tools/gradle/src/main/java/org/teavm/gradle/TeaVMTask.java
rename to tools/gradle/src/main/java/org/teavm/gradle/tasks/TeaVMTask.java
index e30ff6904..dd1e55fea 100644
--- a/tools/gradle/src/main/java/org/teavm/gradle/TeaVMTask.java
+++ b/tools/gradle/src/main/java/org/teavm/gradle/tasks/TeaVMTask.java
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.gradle;
+package org.teavm.gradle.tasks;
 
 import java.io.File;
 import java.io.IOException;
@@ -33,6 +33,7 @@ import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputDirectory;
 import org.gradle.api.tasks.TaskAction;
+import org.teavm.gradle.api.OptimizationLevel;
 import org.teavm.tooling.TeaVMProblemRenderer;
 import org.teavm.tooling.builder.BuildException;
 import org.teavm.tooling.builder.BuildStrategy;