Introduce support for injecting the current invocation index

This commit introduces a new @InvocationIndex annotation for injecting
the current invocation index into @test, @beforeeach, and @AfterEach
methods.

Furthermore, support has been added for injecting the repetition count
for @RepeatedTest methods using @InvocationIndex.

Issues: #14, #214

junit-jupiter-api/src/main/java/org/junit/jupiter/api/InvocationIndex.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2015-2017 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution and is available at
+ *
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+
+package org.junit.jupiter.api;
+
+import static org.junit.platform.commons.meta.API.Usage.Experimental;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.junit.platform.commons.meta.API;
+
+/**
+ * {@code @InvocationIndex} is used to inject the current <em>invocation index</em>
+ * into {@code @Test}, {@code @BeforeEach}, and {@code @AfterEach} methods.
+ *
+ * <p>An invocation index is a counter associated with a given
+ * {@link org.junit.jupiter.api.extension.TestTemplateInvocationContext
+ * TestTemplateInvocationContext}, such as the current repetition in a
+ * {@link RepeatedTest @RepeatedTest}.
+ *
+ * <p>If a method parameter is of type {@code int} or {@code Integer} and
+ * annotated with {@code @InvocationIndex}, JUnit will supply the current
+ * <em>invocation index</em> as the value for the parameter.
+ *
+ * @since 5.0
+ * @see RepeatedTest
+ */
+@Target(ElementType.PARAMETER)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@API(Experimental)
+public @interface InvocationIndex {
+}

junit-jupiter-api/src/main/java/org/junit/jupiter/api/RepeatedTest.java

@@ -28,7 +28,8 @@
  *
  * <p>Each invocation of the repeated test behaves like the execution of a
  * regular {@link Test @Test} method will full support for the same lifecycle
- * callbacks and extensions.
+ * callbacks and extensions. In addition, the current <em>invocation index</em>
+ * (i.e., repetition count) can be injected via {@link InvocationIndex @InvocationIndex}
  *
  * <p>{@code @RepeatedTest} methods must not be {@code private} or {@code static}
  * and must return {@code void}.
@@ -43,6 +44,7 @@
  *
  * @since 5.0
  * @see DisplayName
+ * @see InvocationIndex
  * @see TestInfo
  * @see TestTemplate
  * @see Test
@@ -68,7 +70,8 @@
 	 * <ul>
 	 * <li><code>{displayName}</code>: the {@linkplain TestInfo#getDisplayName
 	 * display name} of the {@code @RepeatedTest} method</li>
-	 * <li><code>{index}</code>: the current invocation index (i.e., repetition count)</li>
+	 * <li><code>{index}</code>: the current <em>invocation index</em> (i.e.,
+	 * repetition count)</li>
 	 * </ul>
 	 *
 	 * <p>Defaults to <code>"{displayName} :: repetition {index}"</code>.

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2015-2017 the original author or authors.
+ *
+ * All rights reserved. This program and the accompanying materials are
+ * made available under the terms of the Eclipse Public License v1.0 which
+ * accompanies this distribution and is available at
+ *
+ * http://www.eclipse.org/legal/epl-v10.html
+ */
+
+package org.junit.jupiter.engine.extension;
+
+import static org.junit.platform.commons.util.AnnotationUtils.isAnnotated;
+
+import org.junit.jupiter.api.InvocationIndex;
+import org.junit.jupiter.api.extension.ExtensionContext;
+import org.junit.jupiter.api.extension.ParameterContext;
+import org.junit.jupiter.api.extension.ParameterResolver;
+
+/**
+ * {@link ParameterResolver} that supports resolution of the current
+ * <em>invocation index</em> for parameters annotated with {@code @InvocationIndex}.
+ *
+ * @since 5.0
+ */
+class InvocationIndexParameterResolver implements ParameterResolver {
+
+	private final Integer invocationIndex;
+
+	InvocationIndexParameterResolver(int invocationIndex) {
+		this.invocationIndex = invocationIndex;
+	}
+
+	@Override
+	public boolean supports(ParameterContext parameterContext, ExtensionContext extensionContext) {
+		return isAnnotated(parameterContext.getParameter(), InvocationIndex.class);
+	}
+
+	@Override
+	public Integer resolve(ParameterContext parameterContext, ExtensionContext extensionContext) {
+		return this.invocationIndex;
+	}
+
+}

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

@@ -41,13 +41,11 @@ public Stream<TestTemplateInvocationContext> provide(ContainerExtensionContext c
 		Method templateMethod = Preconditions.notNull(context.getTestMethod().orElse(null),
 			"test method must not be null");
 
-		RepeatedTestInvocationContext testInvocationContext = new RepeatedTestInvocationContext(
-			createDisplayNameFormatter(templateMethod), context.getDisplayName());
-
 		// @formatter:off
 		return IntStream
 				.rangeClosed(1, getRepeatCount(templateMethod))
-				.mapToObj(n -> testInvocationContext);
+				.mapToObj(n -> new RepeatedTestInvocationContext(n, context.getDisplayName(),
+					createDisplayNameFormatter(templateMethod)));
 		// @formatter:on
 	}
 

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

@@ -10,7 +10,12 @@
 
 package org.junit.jupiter.engine.extension;
 
+import static java.util.Collections.singletonList;
+
+import java.util.List;
+
 import org.junit.jupiter.api.RepeatedTest;
+import org.junit.jupiter.api.extension.Extension;
 import org.junit.jupiter.api.extension.TestTemplateInvocationContext;
 
 /**
@@ -20,17 +25,26 @@
  */
 class RepeatedTestInvocationContext implements TestTemplateInvocationContext {
 
-	private final RepeatedTestDisplayNameFormatter formatter;
+	private final int repetition;
 	private final String displayName;
+	private final RepeatedTestDisplayNameFormatter formatter;
 
-	public RepeatedTestInvocationContext(RepeatedTestDisplayNameFormatter formatter, String displayName) {
-		this.formatter = formatter;
+	public RepeatedTestInvocationContext(int repetition, String displayName,
+			RepeatedTestDisplayNameFormatter formatter) {
+
+		this.repetition = repetition;
 		this.displayName = displayName;
+		this.formatter = formatter;
 	}
 
 	@Override
 	public String getDisplayName(int invocationIndex) {
-		return formatter.format(displayName, invocationIndex);
+		return this.formatter.format(this.displayName, invocationIndex);
+	}
+
+	@Override
+	public List<Extension> getAdditionalExtensions() {
+		return singletonList(new InvocationIndexParameterResolver(this.repetition));
 	}
 
 }

junit-jupiter-engine/src/test/java/org/junit/jupiter/engine/extension/RepeatedTestTests.java

@@ -14,7 +14,10 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.InvocationIndex;
 import org.junit.jupiter.api.RepeatedTest;
 import org.junit.jupiter.api.TestInfo;
 
@@ -27,10 +30,15 @@ class RepeatedTestTests {
 
 	private static int fortyTwo = 0;
 
-	@RepeatedTest(42)
-	void repeatedFortyTwoTimes(TestInfo testInfo) {
-		assertThat(testInfo.getDisplayName()).startsWith("repeatedFortyTwoTimes(TestInfo) :: repetition ");
-		fortyTwo++;
+	@BeforeEach
+	@AfterEach
+	void beforeAndAfterEach(TestInfo testInfo, @InvocationIndex int repetition) {
+		if (testInfo.getDisplayName().startsWith("repeatedOnce")) {
+			assertThat(repetition).isEqualTo(1);
+		}
+		else if (testInfo.getDisplayName().startsWith("repeatedFortyTwoTimes")) {
+			assertThat(repetition).isBetween(1, 42);
+		}
 	}
 
 	@AfterAll
@@ -53,6 +61,12 @@ void repeatedOnce(TestInfo testInfo) {
 		assertThat(testInfo.getDisplayName()).isEqualTo("repeatedOnce(TestInfo) :: repetition 1");
 	}
 
+	@RepeatedTest(42)
+	void repeatedFortyTwoTimes(TestInfo testInfo) {
+		assertThat(testInfo.getDisplayName()).startsWith("repeatedFortyTwoTimes(TestInfo) :: repetition ");
+		fortyTwo++;
+	}
+
 	@RepeatedTest(1)
 	void defaultDisplayName(TestInfo testInfo) {
 		assertThat(testInfo.getDisplayName()).isEqualTo("defaultDisplayName(TestInfo) :: repetition 1");
@@ -88,4 +102,16 @@ void defaultDisplayNameWithPatternIncludingDisplayNameAndIndex(TestInfo testInfo
 			"Repetition #1 for defaultDisplayNameWithPatternIncludingDisplayNameAndIndex(TestInfo)");
 	}
 
+	@RepeatedTest(value = 5, name = "{displayName}")
+	void injectInvocationIndexAsInt(TestInfo testInfo, @InvocationIndex int repetition) {
+		assertThat(testInfo.getDisplayName()).isEqualTo("injectInvocationIndexAsInt(TestInfo, int)");
+		assertThat(repetition).isBetween(1, 5);
+	}
+
+	@RepeatedTest(value = 5, name = "{displayName}")
+	void injectInvocationIndexAsInteger(TestInfo testInfo, @InvocationIndex Integer repetition) {
+		assertThat(testInfo.getDisplayName()).isEqualTo("injectInvocationIndexAsInteger(TestInfo, Integer)");
+		assertThat(repetition).isBetween(1, 5);
+	}
+
 }