Jqwik：如何检查是否涵盖了所有可能性？

Question

How to check if all possibilities (cartesian product of arguments) is covered in summary by N properties? Some of them can be tested few times by different properties.

Answer 1

There's no way in jqwik to assert exhaustive parameter generation across property methods. What you can do, though, is to check all property conditions in a single property method:

@Property(generation = GenerationMode.EXHAUSTIVE)
void fullCartesianProductProperty(
    @ForAll @IntRange(min = 0, max = 1) int p1,
    @ForAll @IntRange(min = 0, max = 3) int p2,
    @ForAll @IntRange(min = 1, max = 3) int p3
) {
    MyEnum result = toCheck(p1, p2, p3);
    if (p1 > 0) {
        // Will only be executed in 12 cases
        assertThat(result)...;
    }
    if (p2 <= 2) {
        // Will only be executed in 18 cases
        assertThat(result)...;
    }
    if (p3 > 1) {
        // Will only be executed in 16 cases
        assertThat(result)...;
    }
    // Will be executed in all 24 cases
    assertThat(result);
}

In this case, all 24 combinations will be executed.

Mind that generation = GenerationMode.EXHAUSTIVE is only necessary if the size of the cartesian product exceeds a property's number of tries (1000 by default).

Answer 2

I found a solution with AfterContainer, but I have a problem with disappearing Statistics after every Property.

private static final StatisticsCollectorImpl CLASS_STATISTICS_COLLECTOR = new StatisticsCollectorImpl("allCases");

Actually I am using manually created StatisticsCollectorImpl and updating it additionally in every Property. So, in result, I have statistics per property and per class.

Statistics.collect(p1, p2, p3);
CLASS_STATISTICS_COLLECTOR.collect(p1, p2, p3);

Fake property allCasesGenerator generates cartesian product.

@Property(generation = GenerationMode.EXHAUSTIVE)
void allCasesGenerator (
    @ForAll @IntRange(min = 0, max = 1) int p1,
    @ForAll @IntRange(min = 0, max = 3) int p2,
    @ForAll @IntRange(min = 1, max = 3) int p3
) {
    CLASS_STATISTICS_COLLECTOR.collect(p1, p2, p3);
}

In AfterContainer I am checking cases existing only once - only from allCasesGenerator.

@AfterContainer
    static void afterAll() {
        final List<String> presentOnlyInAllCasesGeneratorProperty = CLASS_STATISTICS_COLLECTOR.statisticsEntries()
                .stream()
                .filter(entry -> entry.count() <= 1)
                .map(StatisticsEntryImpl::name)
                .collect(Collectors.toList());
        assertThat(presentOnlyInAllCasesGeneratorProperty)
                .isEmpty();
    }