我有一个有一个学生的班级 formatToSpecificText(inputDate: LocalDateTime) 方法将日期更改为文本。在这个方法中，我使用 Duration.between(LocalDateTime.now(), inputDate) 功能。my函数返回具有持续时间的指定文本，例如“超过三天”。
我想为这个类和方法编写单元测试。在这种情况下，我想使用 @RunWith(Parametrized::class) 注解。我的测试类如下所示：

@RunWith(Parameterized::class)
internal class DateTest(private val case: TestCase) {

    private val resources = mock<Resources>()
    private val dateFormatter = mock<DateFormatter>()
    private lateinit var binder: DateBinder
    private val mockedNow: LocalDateTime = LocalDateTime.of(2021, Month.JULY, 21, 12, 0, 0)

    @Before
    fun setUp() {
        binder = DateBinder(resources, dateFormatter)
        whenever(
            resources.getQuantityString(
                R.plurals.over_day,
                1,
                1
            )
        ).thenReturn(OVER_1_DAY_LABEL)
    }

    @Test
    fun `should return formatted time string`() {
        mockStatic(LocalDateTime::class.java).use { mocked ->
            mocked.`when`<Any> { LocalDateTime.now() }.thenAnswer { mockedNow }
            val result = binder.formatToSpecificText(case.given)
            assertThat(case.expected).isEqualTo(result)
        }
    }

    private companion object {
        const val OVER_1_DAY_LABEL = "over 1 day"

        @JvmStatic
        @Parameters(name = "{index}: Test with input={0}")
        fun testCases(): List<TestCase> = listOf(
            TestCase(
                given = LocalDateTime.of(2021, Month.JULY, 22, 12, 0, 0),
                expected = OVER_1_DAY_LABEL
            )
        )
    }

    internal data class TestCase(
        val given: LocalDateTime,
        val expected: String
    )
}

在testcases方法的给定字段中输入的所有内容在binder.formattospecifictext（）中都返回null。

java.lang.NullPointerException
    at java.base/java.time.LocalDateTime.until(LocalDateTime.java:1686)
    at java.base/java.time.Duration.between(Duration.java:488)
    at com.example.DateBinder.formatToSpecificText(DateBinder.kt:17)

我做错了什么？