jqwik - Arbitrary Map - Generate a random number of entries within a Map

问题

This code works to generate a Single Map entry for elements. But I want to generate a random number of entries from within the Map using generateInputMapElements and pass to the statusReturnedFromApplyingRule()

@Property
        //@Report(Reporting.GENERATED)
    boolean statusReturnedFromApplyingRule(@ForAll("generateRule") Rule rule,
                                           @ForAll("generateInputMapElements") Iterable<Map<String, Object>> elements) {
        RangeMatchRule rangeMatchRule = new RangeMatchRule();
        final RuleIF.Status status = rangeMatchRule.applyRule(rule, elements);
        return RuleIF.getEnums().contains(status.toString());
    }

    @Provide
Arbitrary<Iterable<Map<String, Object>>> generateInputMapElements() {
    Arbitrary<Double> metricValueArb = Arbitraries.doubles()
            .between(0, 50.0);

    Arbitrary<Map<String, Object>> inputMapArb =
            metricValueArb.map(metricsValue -> {
                Map<String, Object> inputMap = new HashMap<>();
                inputMap.put(Utils.METRIC_VALUE, metricsValue);
                return inputMap;
            });
    return inputMapArb.map(inputMap -> {
        List<Map<String, Object>> inputMapLst = new ArrayList<>();
        inputMapLst.add(inputMap);
        return inputMapLst;
    });
}

How to write a jqwik generator method with nested generators

回答1:

Assuming that you want a list (iterable) of maps with a single entry, I see two basic options.

Option 1 - Use Arbitrary.list() to generate a list and specify min and max size directly in the generator code:

@Provide
Arbitrary<List<Map<String, Object>>> generateInputMapElements() {
    Arbitrary<Double> metricValueArb = Arbitraries.doubles()
                                                  .between(0, 50.0);

    return metricValueArb
        .map(metricsValue -> {
            Map<String, Object> inputMap = new HashMap<>();
            inputMap.put(Utils.METRIC_VALUE, metricsValue);
            return inputMap;
        })
        .list().ofMinSize(1).ofMaxSize(10);
}

Option 2 - Generate only the individual maps and use standard annotations for the iterable:

@Property
@Report(Reporting.GENERATED)
boolean statusReturnedFromApplyingRule2(
    @ForAll("generateRule") Rule rule,
    @ForAll @Size(min = 1, max = 10) Iterable<@From("generateInputMap") Map<String, Object>> elements
) {
    ...
}

@Provide
Arbitrary<Map<String, Object>> generateInputMap() {
    Arbitrary<Double> metricValueArb = Arbitraries.doubles()
                                                  .between(0, 50.0);

    return metricValueArb
        .map(metricsValue -> {
            Map<String, Object> inputMap = new HashMap<>();
            inputMap.put(Utils.METRIC_VALUE, metricsValue);
            return inputMap;
        });
}

I'd personally go with option 2 because it requires less code. YMMV though.

来源：https://stackoverflow.com/questions/58548769/jqwik-arbitrary-map-generate-a-random-number-of-entries-within-a-map

标签

junit5

jqwik