Feed multiple parameters in JUnit 5 test method

Acsor :

I want to provide my codebase with "polymorphic" test cases. Specifically, there are going to be multiple implementations of a Graph interface and would like to reuse the test code for all of them (ALGraph, AMGraph, ...).

I'd like to develop my test methods along the following lines

    @ParameterizedTest
    @MethodSource("graphFactory")
    // Note: JUnit 5 won't allow the following additional argument source
    @ValueSource(ints = {0, 31415, -31415})
    void testInsertDeleteNode(Graph g, Integer v) {
        g.insertNode(new Node<>(v));
        assertTrue(g.containsNode(new Node<>(v)));
        assertEquals(1, g.vertices().size());

        g.deleteNode(new Node<>(v));
        assertFalse(g.containsNode(new Node<>(v)));
        assertEquals(0, g.vertices().size());
    }

but the way JUnit is built is preventing me from accomplishing this scheme.

So basically I'd like to provide a cartesian product of multiple arguments to my tests. Is that possible with the out-of-the-box argument providers (ValueSource, NullSource, ...) or do I forcibly need to set up customized ones with the aid of @MethodSource?

Sormuras :

It's not supported out of the box -- but there already exists a feature request at https://github.com/junit-team/junit5/issues/1427

Find an example and proof of concept solution here: https://github.com/junit-team/junit5-samples/tree/master/junit5-jupiter-extensions

@CartesianProductTest({"0", "1"})
void threeBits(String a, String b, String c) {
    int value = Integer.parseUnsignedInt(a + b + c, 2);
    assertTrue((0b000 <= value) && (value <= 0b111));
}

@CartesianProductTest
@DisplayName("S ⨯ T ⨯ U")
void nFold(String string, Class<?> type, TimeUnit unit, TestInfo info) {
    assertTrue(string.endsWith("a"));
    assertTrue(type.isInterface());
    assertTrue(unit.name().endsWith("S"));
    assertTrue(info.getTags().isEmpty());
}

static CartesianProductTest.Sets nFold() {
    return new CartesianProductTest.Sets()
            .add("Alpha", "Omega")
            .add(Runnable.class, Comparable.class, TestInfo.class)
            .add(TimeUnit.DAYS, TimeUnit.HOURS);
}

Yields a test plan like:

Feed multiple parameters in JUnit 5 test method

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