不兼容的類型：不存在類型變量 T 的實例，因此 Matcher<t> 符合 ArgumentMatcher<long></long></t>

Question

private long userId = 1;

@Before
    public void before() {
        when(userStatisticsDAO.findByUserIDAndCurrency(longThat(isLessThanOrEqualTo(userId)), any(Currency.class))).thenReturn(userStatistics);
    }

    public static <T extends Comparable<T>> Matcher<T> isLessThanOrEqualTo(T value) {
        return OrderingComparison.lessThanOrEqualTo(value);
    }

錯誤發生在：

longThat(isLessThanOrEqualTo(userId)

incompatible types: no instance(s) of type variable(s) T exist so that Matcher<T> conforms to ArgumentMatcher<Long>

Answer 1

您可以創建一個ArgumentMatcher實現以與longThat(...)一起使用。

您創建的isLessThanOrEqualTo方法不是longThat(...)方法所期望的ArgumentMatcher類型。

請參閱下面的示例

@Test
public void test() {
    long userId = 10;

    when(userStatisticsDAO.findByUserIDAndCurrency(
        ArgumentMatchers.longThat(new LessThanEquals(userId)), any(Currency.class)))
           .thenReturn(userStatistics);

    Assert.assertNull(userStatisticsDAO.findByUserIDAndCurrency(199, currency));
    Assert.assertNotNull(userStatisticsDAO.findByUserIDAndCurrency(1, currency));
    Assert.assertNotNull(userStatisticsDAO.findByUserIDAndCurrency(10, currency));
}

class LessThanEquals implements ArgumentMatcher<Long> {
    final long limit;

    public LessThanEquals(long limit) {
        this.limit = limit;
    }

    public boolean matches(Long input) {
        return input != null && input <= limit;
    }
}

// Don't use this, since it's not returning an ArgumentMatcher
public static <T extends Comparable<T>> Matcher<T> isLessThanOrEqualTo(T value) {
    return OrderingComparison.lessThanOrEqualTo(value);
}

參考： https://www.baeldung.com/mockito-argument-matchers