Small improvements and documentation following PR #3085

Author: juliette-derancourt

documentation/src/docs/asciidoc/release-notes/release-notes-5.10.0-M1.adoc

@@ -42,7 +42,8 @@ repository on GitHub.
 
 ==== New Features and Improvements
 
-* New `ArgumentsAccessor.getInvocationIndex` method to supply index of a `@ParameterizedTest` invocation.
+* New `ArgumentsAccessor.getInvocationIndex()` method that supplies the index of a
+  `@ParameterizedTest` invocation.
 
 
 [[release-notes-5.10.0-M1-junit-vintage]]

documentation/src/docs/asciidoc/user-guide/writing-tests.adoc

@@ -1769,6 +1769,9 @@ this API, you can access the provided arguments through a single argument passed
 test method. In addition, type conversion is supported as discussed in
 <<writing-tests-parameterized-tests-argument-conversion-implicit>>.
 
+Besides, you can retrieve the current test invocation index with
+`ArgumentsAccessor.getInvocationIndex()`.
+
 [source,java,indent=0]
 ----
 include::{testDir}/example/ParameterizedTestDemo.java[tags=ArgumentsAccessor_example]

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

@@ -213,7 +213,9 @@ Resolver createResolver(ParameterContext parameterContext) {
 	}
 
 	interface Resolver {
+
 		Object resolve(ParameterContext parameterContext, Object[] arguments, int invocationIndex);
+
 	}
 
 	static class Converter implements Resolver {

junit-jupiter-params/src/main/java/org/junit/jupiter/params/aggregator/DefaultArgumentsAccessor.java

@@ -35,13 +35,14 @@
 @API(status = INTERNAL, since = "5.2")
 public class DefaultArgumentsAccessor implements ArgumentsAccessor {
 
-	private final Object[] arguments;
 	private final int invocationIndex;
+	private final Object[] arguments;
 
 	public DefaultArgumentsAccessor(int invocationIndex, Object... arguments) {
+		Preconditions.condition(invocationIndex >= 1, () -> "invocation index must be >= 1");
 		Preconditions.notNull(arguments, "Arguments array must not be null");
-		this.arguments = arguments;
 		this.invocationIndex = invocationIndex;
+		this.arguments = arguments;
 	}
 
 	@Override

junit-jupiter-params/src/test/java/org/junit/jupiter/params/aggregator/AggregatorIntegrationTests.java

@@ -184,6 +184,20 @@ void reportsExceptionForErroneousAggregator() {
 					message("Error aggregating arguments for parameter at index 0: something went horribly wrong"))));
 	}
 
+	@ParameterizedTest
+	@CsvSource({ //
+			"first", //
+			"second" //
+	})
+	void argumentsAccessorInvocationIndex(ArgumentsAccessor arguments) {
+		if ("first".equals(arguments.getString(0))) {
+			assertEquals(1, arguments.getInvocationIndex());
+		}
+		if ("second".equals(arguments.getString(0))) {
+			assertEquals(2, arguments.getInvocationIndex());
+		}
+	}
+
 	private void testPersonAggregator(Person person) {
 		if (person.firstName.equals("Jane")) {
 			assertEquals("Jane Doe", person.getFullName());
@@ -208,17 +222,6 @@ private EngineExecutionResults execute(DiscoverySelector... selectors) {
 		return EngineTestKit.execute("junit-jupiter", request().selectors(selectors).build());
 	}
 
-	@ParameterizedTest
-	@CsvSource({ "first", "second" })
-	void argumentsAccessorInvocationIndex(ArgumentsAccessor arguments) {
-		if ("first".equals(arguments.getString(0))) {
-			assertEquals(1, arguments.getInvocationIndex());
-		}
-		if ("second".equals(arguments.getString(0))) {
-			assertEquals(2, arguments.getInvocationIndex());
-		}
-	}
-
 	// -------------------------------------------------------------------------
 
 	public static class Person {

junit-jupiter-params/src/test/kotlin/org/junit/jupiter/params/aggregator/ArgumentsAccessorKotlinTests.kt

@@ -21,14 +21,14 @@ class ArgumentsAccessorKotlinTests {
 
     @Test
     fun `get() with reified type and index`() {
-        assertEquals(1, DefaultArgumentsAccessor(0, 1).get<Int>(0))
-        assertEquals('A', DefaultArgumentsAccessor(0, 'A').get<Char>(0))
+        assertEquals(1, DefaultArgumentsAccessor(1, 1).get<Int>(0))
+        assertEquals('A', DefaultArgumentsAccessor(1, 'A').get<Char>(0))
     }
 
     @Test
     fun `get() with reified type and index for incompatible type`() {
         val exception = assertThrows<ArgumentAccessException> {
-            DefaultArgumentsAccessor(0, Integer.valueOf(1)).get<Char>(0)
+            DefaultArgumentsAccessor(1, Integer.valueOf(1)).get<Char>(0)
         }
 
         assertThat(exception).hasMessage(
@@ -38,13 +38,13 @@ class ArgumentsAccessorKotlinTests {
 
     @Test
     fun `get() with index`() {
-        assertEquals(1, DefaultArgumentsAccessor(0, 1).get(0))
-        assertEquals('A', DefaultArgumentsAccessor(0, 'A').get(0))
+        assertEquals(1, DefaultArgumentsAccessor(1, 1).get(0))
+        assertEquals('A', DefaultArgumentsAccessor(1, 'A').get(0))
     }
 
     @Test
     fun `get() with index and class reference`() {
-        assertEquals(1, DefaultArgumentsAccessor(0, 1).get(0, Integer::class.java))
-        assertEquals('A', DefaultArgumentsAccessor(0, 'A').get(0, Character::class.java))
+        assertEquals(1, DefaultArgumentsAccessor(1, 1).get(0, Integer::class.java))
+        assertEquals('A', DefaultArgumentsAccessor(1, 'A').get(0, Character::class.java))
     }
 }