Allow Stream<? extends TestTemplateInvocationContext> return types (#4750)

For consistency with `ClassTemplateInvocationContextProvider` and to
make implementations simpler, this commit changes the return type of the
`provideTestTemplateInvocationContexts(ExtensionContext)` method of the
`TestTemplateInvocationContextProvider` interface to allow more concrete
`Streams` to be returned.

This change is source compatible, meaning implementations will still
compile when declaring `Stream<TestTemplateInvocationContext>` as method
return type. To check for binary compatibility, I used Pioneer's
`RetryingTestExtension` with a 6.0.0-SNAPSHOT that included this change.
The extension kept working. Nevertheless, I included this change as
potentially breaking in the release notes.

Resolves #3577.

Author: marcphilipp

documentation/src/docs/asciidoc/release-notes/release-notes-6.0.0-M2.adoc

@@ -61,7 +61,10 @@ repository on GitHub.
 [[release-notes-6.0.0-M2-junit-jupiter-deprecations-and-breaking-changes]]
 ==== Deprecations and Breaking Changes
 
-* ❓
+* Change return type of `provideTestTemplateInvocationContexts(ExtensionContext)` method
+  of the `TestTemplateInvocationContextProvider` interface from
+  `Stream<TestTemplateInvocationContext>` to
+  `Stream<? extends TestTemplateInvocationContext>`.
 
 [[release-notes-6.0.0-M2-junit-jupiter-new-features-and-improvements]]
 ==== New Features and Improvements

junit-jupiter-api/src/main/java/org/junit/jupiter/api/extension/TestTemplateInvocationContextProvider.java

@@ -91,7 +91,7 @@ public interface TestTemplateInvocationContextProvider extends Extension {
 	 * @see #supportsTestTemplate
 	 * @see ExtensionContext
 	 */
-	Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context);
+	Stream<? extends TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context);
 
 	/**
 	 * Signal that this provider may provide zero

junit-jupiter-engine/src/main/java/org/junit/jupiter/engine/extension/RepeatedTestExtension.java

@@ -20,7 +20,6 @@
 
 import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.extension.ExtensionContext;
-import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContextProvider;
 import org.junit.platform.commons.util.Preconditions;
 
@@ -38,7 +37,7 @@ public boolean supportsTestTemplate(ExtensionContext context) {
 	}
 
 	@Override
-	public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context) {
+	public Stream<RepeatedTestInvocationContext> provideTestTemplateInvocationContexts(ExtensionContext context) {
 		Method testMethod = context.getRequiredTestMethod();
 		String displayName = context.getDisplayName();
 		RepeatedTest repeatedTest = findAnnotation(testMethod, RepeatedTest.class).get();

junit-jupiter-params/src/main/java/org/junit/jupiter/params/ParameterizedClassContext.java

@@ -28,13 +28,12 @@
 import java.util.function.Predicate;
 
 import org.junit.jupiter.api.TestInstance;
-import org.junit.jupiter.api.extension.ClassTemplateInvocationContext;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.platform.commons.JUnitException;
 import org.junit.platform.commons.support.HierarchyTraversalMode;
 import org.junit.platform.commons.util.ReflectionUtils;
 
-class ParameterizedClassContext implements ParameterizedDeclarationContext<ClassTemplateInvocationContext> {
+class ParameterizedClassContext implements ParameterizedDeclarationContext<ParameterizedClassInvocationContext> {
 
 	private final Class<?> testClass;
 	private final ParameterizedClass annotation;
@@ -124,7 +123,7 @@ public ResolverFacade getResolverFacade() {
 	}
 
 	@Override
-	public ClassTemplateInvocationContext createInvocationContext(ParameterizedInvocationNameFormatter formatter,
+	public ParameterizedClassInvocationContext createInvocationContext(ParameterizedInvocationNameFormatter formatter,
 			Arguments arguments, int invocationIndex) {
 		return new ParameterizedClassInvocationContext(this, formatter, arguments, invocationIndex);
 	}

junit-jupiter-params/src/main/java/org/junit/jupiter/params/ParameterizedClassExtension.java

@@ -21,7 +21,6 @@
 import java.util.stream.Stream;
 
 import org.junit.jupiter.api.TestInstance;
-import org.junit.jupiter.api.extension.ClassTemplateInvocationContext;
 import org.junit.jupiter.api.extension.ClassTemplateInvocationContextProvider;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
@@ -35,7 +34,7 @@
 /**
  * @since 5.13
  */
-class ParameterizedClassExtension extends ParameterizedInvocationContextProvider<ClassTemplateInvocationContext>
+class ParameterizedClassExtension extends ParameterizedInvocationContextProvider<ParameterizedClassInvocationContext>
 		implements ClassTemplateInvocationContextProvider, ParameterResolver {
 
 	private static final String DECLARATION_CONTEXT_KEY = "context";
@@ -70,7 +69,7 @@ public boolean supportsClassTemplate(ExtensionContext extensionContext) {
 	}
 
 	@Override
-	public Stream<? extends ClassTemplateInvocationContext> provideClassTemplateInvocationContexts(
+	public Stream<ParameterizedClassInvocationContext> provideClassTemplateInvocationContexts(
 			ExtensionContext extensionContext) {
 
 		return provideInvocationContexts(extensionContext, getDeclarationContext(extensionContext));

junit-jupiter-params/src/main/java/org/junit/jupiter/params/ParameterizedTestContext.java

@@ -12,7 +12,6 @@
 
 import java.lang.reflect.Method;
 
-import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.platform.commons.util.Preconditions;
 
@@ -22,7 +21,7 @@
  *
  * @since 5.3
  */
-class ParameterizedTestContext implements ParameterizedDeclarationContext<TestTemplateInvocationContext> {
+class ParameterizedTestContext implements ParameterizedDeclarationContext<ParameterizedTestInvocationContext> {
 
 	private final Class<?> testClass;
 	private final Method method;
@@ -77,7 +76,7 @@ public ResolverFacade getResolverFacade() {
 	}
 
 	@Override
-	public TestTemplateInvocationContext createInvocationContext(ParameterizedInvocationNameFormatter formatter,
+	public ParameterizedTestInvocationContext createInvocationContext(ParameterizedInvocationNameFormatter formatter,
 			Arguments arguments, int invocationIndex) {
 		return new ParameterizedTestInvocationContext(this, formatter, arguments, invocationIndex);
 	}

junit-jupiter-params/src/main/java/org/junit/jupiter/params/ParameterizedTestExtension.java

@@ -18,13 +18,12 @@
 
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ExtensionContext.Namespace;
-import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContextProvider;
 
 /**
  * @since 5.0
  */
-class ParameterizedTestExtension extends ParameterizedInvocationContextProvider<TestTemplateInvocationContext>
+class ParameterizedTestExtension extends ParameterizedInvocationContextProvider<ParameterizedTestInvocationContext>
 		implements TestTemplateInvocationContextProvider {
 
 	static final String DECLARATION_CONTEXT_KEY = "context";
@@ -45,7 +44,7 @@ public boolean supportsTestTemplate(ExtensionContext context) {
 	}
 
 	@Override
-	public Stream<TestTemplateInvocationContext> provideTestTemplateInvocationContexts(
+	public Stream<ParameterizedTestInvocationContext> provideTestTemplateInvocationContexts(
 			ExtensionContext extensionContext) {
 
 		return provideInvocationContexts(extensionContext, getDeclarationContext(extensionContext));