Parametrisierte Tests mit @CsvSource und @MethodSource

Warum parametrisierte Tests?

@ValueSource: Einfache Tests mit einem Wert

@ParameterizedTest
@ValueSource(strings = {"", "  ", "\t"})
void blank_strings_are_rejected(String input) {
    assertThrows(IllegalArgumentException.class, () -> validator.validate(input));
}

@CsvSource: Mehrere Parameter inline

@ParameterizedTest
@CsvSource({
    "Alice, 30, true",
    "Bob,   17, false",
    "Carol, 0,  false"
})
void test_adult_check(String name, int age, boolean expectedAdult) {
    User user = new User(name, age);
    assertEquals(expectedAdult, user.isAdult());
}

@CsvSource mit delimiterString

@ParameterizedTest
@CsvSource(value = {
    "Alice | 30 | ADMIN",
    "Bob   | 25 | USER"
}, delimiterString = "|")
void test_roles(String name, int age, String role) { ... }

@CsvFileSource: Externe Datendateien

@ParameterizedTest
@CsvFileSource(resources = "/test-data/users.csv", numLinesToSkip = 1)
void test_from_file(String name, int age, boolean expected) {
    assertEquals(expected, service.isEligible(name, age));
}

@MethodSource: Komplexe Parameter

@ParameterizedTest
@MethodSource("provideOrders")
void test_total_calculation(Order order, BigDecimal expected) {
    assertEquals(expected, orderService.calculateTotal(order));
}
static Stream<Arguments> provideOrders() {
    return Stream.of(
        Arguments.of(new Order(List.of(item(10), item(20))), BigDecimal.valueOf(30)),
        Arguments.of(new Order(List.of()),                   BigDecimal.ZERO)
    );
}

@EnumSource: Alle Enum-Werte testen

@ParameterizedTest
@EnumSource(value = UserStatus.class, mode = EnumSource.Mode.EXCLUDE, names = "DELETED")
void test_active_statuses(UserStatus status) {
    assertTrue(notificationService.shouldNotify(status));
}

@NullAndEmptySource

@ParameterizedTest
@NullAndEmptySource
void null_and_empty_are_invalid(String input) {
    assertFalse(validator.isValid(input));
}

Benutzerdefinierte Anzeigenamen

@ParameterizedTest(name = "age={1} should be adult={2}")
@CsvSource({"Alice, 30, true", "Bob, 17, false"})
void test_adult(String name, int age, boolean expected) { ... }

Quellen mit @ArgumentsSource kombinieren

public class UserArgumentsProvider implements ArgumentsProvider {
    public Stream<? extends Arguments> provideArguments(ExtensionContext ctx) {
        return Stream.of(
            Arguments.of(new User("Alice", 30)),
            Arguments.of(new User("Bob", 17))
        );
    }
}
@ParameterizedTest
@ArgumentsSource(UserArgumentsProvider.class)
void test_user(User user) { ... }

Parametrisierte Tests für Grenzwerte

@ParameterizedTest
@CsvSource({"0, false", "1, true", "100, true", "101, false"})
void test_range_boundaries(int value, boolean expected) {
    assertEquals(expected, validator.isInRange(value, 1, 100));
}

Kurzer Test

Zusammenfassung