单元测试 |使用 Mockk.io 模拟 FileOutputStream

Question

我需要从下面提到的方法中测试三件事：

• 验证output.write(any<ByteArray>())被调用
• 验证output.close()被调用
• 断言返回fullPath

fun saveFile(fullPath: String, model: SomeDataModel): String? {
        try {
            val output = FileOutputStream(fullPath)
            output.write(Base64.decode(model.someString, Base64.DEFAULT))
            output.close()
        } catch (e: IOException) {
            return null
        }
        return fullPath
 }

面临的问题：

• 嘲讽FileOutputStream

试过：

    @Test
    fun `saveFile returns file path if fileOutputStream write succeeds`() {
        val fullPath = "test/full/path"
        val model = SomeDataModel()
        val stringByteArray: ByteArray? = someModel.someString?.toByteArray(Charset.defaultCharset())


        mockkStatic("android.util.Base64")
        every { Base64.decode(model.someString, Base64.DEFAULT) } returns stringByteArray

        mockkConstructor(FileOutputStream::class)
        val fileOutputStream = mockk<FileOutputStream>()
        every { constructedWith<FileOutputStream>(OfTypeMatcher<String>(String::class)) } returns fileOutputStream
        // Getting error on above line: Missing mocked calls inside every { ... } block: make sure the object inside the block is a mock

        every { saveFile(fullPath, model) } returns filePath

        val result = saveFile(fullPath, model)

        verify { fileOutputStream.write(stringByteArray) }

        assertEquals(fullPath, result)
    }

请帮助我使用 Mockk.io/Mockito 编写正确的测试用例

Answer 1

在every { constructedWith<FileOutputStream>(OfTypeMatcher<String>(String::class)) } returns fileOutputStream 行中，您不能返回模拟对象fileOutputStream，而是一个非模拟对象。看看https://mockk.io/#constructor-mocks