Deprecate support for running JUnit tests

Closes #2847

Author: krmahadevan

CHANGES.txt

@@ -1,5 +1,6 @@
 Current
 Fixed: GITHUB-2792: JUnitTestClass sets XmlTest as null when running JUnit 4 Tests using TestNG (Krishnan Mahadevan)
+Fixed: GITHUB-2847: Deprecate support for running JUnit tests (Krishnan Mahadevan)
 Fixed: GITHUB-2844: Deprecate support for running Spock Tests (Krishnan Mahadevan)
 Fixed: GITHUB-550: Weird @BeforeMethod and @AfterMethod behaviour with dependsOnMethods (Krishnan Mahadevan)
 Fixed: GITHUB-893: TestNG should provide an Api which allow to find all dependent of a specific test (Krishnan Mahadevan)

testng-core/src/main/java/org/testng/TestRunner.java

@@ -15,6 +15,7 @@
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.PriorityBlockingQueue;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -646,7 +647,18 @@ private void invokeTestConfigurations(ITestNGMethod[] testConfigurationMethods)
 
   private ITestNGMethod[] m_allJunitTestMethods = new ITestNGMethod[] {};
 
+  private static final AtomicBoolean warnOnce = new AtomicBoolean(false);
+
   private void privateRunJUnit() {
+    if (warnOnce.compareAndSet(false, true)) {
+      String msg =
+          "Support to run JUnit tests using TestNG stands deprecated "
+              + "and will be removed in future versions. You can now use the JUnit5 TestNG "
+              + "engine to run both JUnit and TestNG tests. For more information refer to "
+              + "https://github.com/junit-team/testng-engine .";
+      Logger.getLogger(TestRunner.class).warn(msg);
+    }
+
     final ClassInfoMap cim = new ClassInfoMap(m_testClassesFromXml, false);
     final Set<Class<?>> classes = cim.getClasses();
     final List<ITestNGMethod> runMethods = Lists.newArrayList();
@@ -656,7 +668,7 @@ private void privateRunJUnit() {
     // The resolution process is not specified in the JVM spec with a specific implementation,
     // so it can be eager => failure
     workers.add(
-        new IWorker<ITestNGMethod>() {
+        new IWorker<>() {
           /** @see TestMethodWorker#getTimeOut() */
           @Override
           public long getTimeOut() {

testng-core/src/main/java/org/testng/junit/IJUnitTestRunner.java

@@ -9,7 +9,12 @@
 import org.testng.internal.ITestResultNotifier;
 import org.testng.internal.Utils;
 
-/** An abstraction interface over JUnit test runners. */
+/**
+ * An abstraction interface over JUnit test runners.
+ *
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public interface IJUnitTestRunner {
 
   void setInvokedMethodListeners(Collection<IInvokedMethodListener> listener);

testng-core/src/main/java/org/testng/junit/JUnit3TestClass.java

@@ -2,7 +2,10 @@
 
 import junit.framework.Test;
 
-/** @author lukas */
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit3TestClass extends JUnitTestClass {
 
   public JUnit3TestClass(Test test) {

testng-core/src/main/java/org/testng/junit/JUnit3TestMethod.java

@@ -6,6 +6,10 @@
 import org.testng.internal.ConstructorOrMethod;
 import org.testng.internal.Utils;
 
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit3TestMethod extends JUnitTestMethod {
 
   public JUnit3TestMethod(ITestObjectFactory objectFactory, JUnitTestClass owner, Test test) {

testng-core/src/main/java/org/testng/junit/JUnit3TestRecognizer.java

@@ -4,7 +4,10 @@
 import java.lang.reflect.Modifier;
 import junit.framework.Test;
 
-/** @author lukas */
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit3TestRecognizer implements JUnitTestRecognizer {
 
   public JUnit3TestRecognizer() {}

testng-core/src/main/java/org/testng/junit/JUnit4ConfigurationMethod.java

@@ -3,6 +3,10 @@
 import java.lang.reflect.Method;
 import org.testng.internal.ConstructorOrMethod;
 
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit4ConfigurationMethod extends ConstructorOrMethod {
 
   private final Class<?> declaringClass;

testng-core/src/main/java/org/testng/junit/JUnit4TestClass.java

@@ -2,7 +2,10 @@
 
 import org.junit.runner.Description;
 
-/** @author lukas */
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit4TestClass extends JUnitTestClass {
 
   public JUnit4TestClass(Description test) {

testng-core/src/main/java/org/testng/junit/JUnit4TestMethod.java

@@ -7,6 +7,10 @@
 import org.testng.internal.Utils;
 import org.testng.log4testng.Logger;
 
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public class JUnit4TestMethod extends JUnitTestMethod {
 
   private static final AtomicBoolean warnOnce = new AtomicBoolean(false);

testng-core/src/main/java/org/testng/junit/JUnit4TestRecognizer.java

@@ -4,7 +4,10 @@
 import java.lang.reflect.Method;
 import org.junit.runner.RunWith;
 
-/** @author lukas */
+/**
+ * @deprecated - Support for running JUnit tests stands deprecated as of TestNG <code>7.6.2</code>
+ */
+@Deprecated
 public final class JUnit4TestRecognizer implements JUnitTestRecognizer {
 
   public JUnit4TestRecognizer() {}