Annotation Type MethodSource
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@Target({ANNOTATION_TYPE,METHOD}) @Retention(RUNTIME) @Documented @API(status=EXPERIMENTAL, since="5.0") @ArgumentsSource(org.junit.jupiter.params.provider.MethodArgumentsProvider.class) public @interface MethodSource@MethodSourceis anArgumentsSourcewhich provides access to values returned from factory methods of the class in which this annotation is declared or from static factory methods in external classes referenced by fully qualified method name.Each factory method must generate a stream of arguments, and each set of "arguments" within the "stream" will be provided as the physical arguments for individual invocations of the annotated
@ParameterizedTestmethod. Generally speaking this translates to aStreamofArguments(i.e.,Stream<Arguments>); however, the actual concrete return type can take on many forms. In this context, a "stream" is anything that JUnit can reliably convert into aStream, such asStream,DoubleStream,LongStream,IntStream,Collection,Iterator,Iterable, an array of objects, or an array of primitives. Each set of "arguments" within the "stream" can be supplied as an instance ofArguments, an array of objects (e.g.,Object[],String[], etc.), or a single value if the parameterized test method accepts a single argument.Please note that a one-dimensional array of objects supplied as a set of "arguments" will be handled differently than other types of arguments. Specifically, all of the elements of a one-dimensional array of objects will be passed as individual physical arguments to the
@ParameterizedTestmethod. This behavior can be seen in the table below for thestatic Stream<Object[]> factory()method: the@ParameterizedTestmethod accepts individualStringandintarguments rather than a singleObject[]array. In contrast, any multidimensional array supplied as a set of "arguments" will be passed as a single physical argument to the@ParameterizedTestmethod without modification. This behavior can be seen in the table below for thestatic Stream<int[][]> factory()andstatic Stream<Object[][]> factory()methods: the@ParameterizedTestmethods for those factories accept individualint[][]andObject[][]arguments, respectively.Examples
The following table displays compatible method signatures for parameterized test methods and their corresponding factory methods.
@ParameterizedTestmethodFactory method void test(int)static int[] factory()void test(int)static IntStream factory()void test(String)static String[] factory()void test(String)static List<String> factory()void test(String)static Stream<String> factory()void test(String, String)static String[][] factory()void test(String, int)static Object[][] factory()void test(String, int)static Stream<Object[]> factory()void test(String, int)static Stream<Arguments> factory()void test(int[])static int[][] factory()void test(int[])static Stream<int[]> factory()void test(int[][])static Stream<int[][]> factory()void test(Object[][])static Stream<Object[][]> factory()Factory methods within the test class must be
staticunless thePER_CLASStest instance lifecycle mode is used; whereas, factory methods in external classes must always bestatic. In any case, factory methods must not declare any parameters.- Since:
- 5.0
- See Also:
Arguments,ArgumentsSource,ParameterizedTest,TestInstance
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Optional Element Summary
Optional Elements Modifier and Type Optional Element Description java.lang.String[]valueThe names of factory methods within the test class or in external classes to use as sources for arguments.
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Element Detail
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value
java.lang.String[] value
The names of factory methods within the test class or in external classes to use as sources for arguments.Factory methods in external classes must be referenced by fully qualified method name — for example,
com.example.StringsProviders#blankStrings.If no factory method names are declared, a method within the test class that has the same name as the test method will be used as the factory method by default.
For further information, see the class-level Javadoc.
- Default:
- {""}
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