存根方法時獲取 InvalidUseOfMatchersException

Question

我在我的 Android 項目中使用 mockito 來測試將QuerySnapshot轉換為List<Entry>的函數。

這是我要測試的功能：

class EntriesMapper {

    fun map(querySnapshot: QuerySnapshot): List<Entry> {
        return querySnapshot.map { documentSnapshot ->
            Entry(documentSnapshot["id"] as String)
        }
    }
}

這是測試類：

class EntriesMapperTest {
    @Test
    fun `map should convert query snapshot to entry`() {
        val id = 1
        val documentSnapshot = mock<DocumentSnapshot> {
            on { this.id } doReturn id
        }
        val querySnapshot = mock<QuerySnapshot>()
        val transform = any<(DocumentSnapshot) -> Entry>()
        whenever(querySnapshot.map(transform)).thenAnswer { answer ->
            (answer.arguments.first() as (DocumentSnapshot) -> Entry).invoke(documentSnapshot)
        }
        val testObject = EntriesMapper()

        val entries = testObject.map(querySnapshot)
        val entry = entries.first()

        assertThat(entry.id, equalTo(id))
    }
}

這是例外：

org.mockito.exceptions.misusing.InvalidUseOfMatchersException: 
Invalid use of argument matchers!
0 matchers expected, 1 recorded:
-> at io.company.myapp.entries.EntriesMapperTest.map should convert query snapshot to entry(EntriesMapperTest.kt:147)

This exception may occur if matchers are combined with raw values:
    //incorrect:
    someMethod(anyObject(), "raw String");
When using matchers, all arguments have to be provided by matchers.
For example:
    //correct:
    someMethod(anyObject(), eq("String by matcher"));

我知道這是一個非常常見的例外，當您將匹配器與原始值結合使用時，但正如您所看到的，我沒有傳入原始值。

Answer 1

我決定模擬 QuerySnapshot 的原因是它的構造函數是私有的，並且使用 mockito 刪除 map 函數最終會產生比解決方案更多的問題。

QuerySnapshot 繼承自 Iterable，因此我建議使用 List 而不是使用模擬。

class EntriesMapper {
    fun map(querySnapshot: Iterable<DocumentSnapshot>): List<Entry> {
        return querySnapshot.map { documentSnapshot ->
            Entry(documentSnapshot["id"] as String)
    }
}

測試班

class EntriesMapperTest {
    @Test
    fun `map should convert query snapshot to entry`() {
        val id = 1
        val documentSnapshot = mock<DocumentSnapshot> {
            on { this.id } doReturn id
        }
        val testObject = EntriesMapper()

        val entries = testObject.map(listOf(documentSnapshot))
        val entry = entries.first()

        assertThat(entry.id, equalTo(id))
    }
}