java - 在用于测试 Junit4 的函数中模拟私有(private)变量

Question

我正在为一个函数编写一个 Junit4 测试，该函数具有基于其他函数设置的 boolean 变量。如何在我的测试用例中模拟这些 boolean 变量。

我正在测试的功能

private var operatorSigned = false
private var engineerSigned = false


override fun onValidationSucceeded() {
    if (operatorSigned && engineerSigned) {
        sendQualityControlCheck()
    } else {
        view.showToastMessage(app.getString(R.string.quality_control_signatures_not_complete))
    }
}

这就是设置值的方式

override fun signatureSigned(name: String, svgSignature: String, bitmapSignature: Bitmap, signatureType: SignatureType) {
    val svgSignatureGzipped = CompressionTools.gzipCompress(svgSignature)
    when (signatureType) {
        SignatureType.OPERATOR -> {
            operatorSignature = QualityControlSignature(svgSignatureGzipped, DateTime())
            operatorSigned = true
            view.operatorSignatureSigned()
        }
        SignatureType.ENGINEER -> {
            engineerSignature = QualityControlSignature(svgSignatureGzipped, DateTime())
            engineerSigned = true
            engineerName = name
            view.engineerSignatureSigned()
        }
    }
}

我的测试用例

@Test
fun `must show toast message when onValidationSucceeded is called and operatorSigned is false`() {
    `when`(app.getString(R.string.quality_control_signatures_not_complete)).thenReturn("Operator and Engineer signature required")
    presenter.onValidationSucceeded()
    verify(view).showToastMessage("Operator and Engineer signature required")
}

我希望能够更改 operatorSigned 和 EngineerSigned 的值我该怎么做。

Answer 1

让我们假装OPERATOR您的代码路径将这些 boolean 值设置为 false:

@Test
fun `must show toast message when onValidationSucceeded is called and signature is Operator`() {
    // Given
    signatureSigned("unusedName", "unusedSig", null, SignatureType.OPERATOR) 
`when`(app.getString(R.string.quality_control_signatures_not_complete)).thenReturn("Operator and Engineer signature required")
    // When
    presenter.onValidationSucceeded()
    // Then
    verify(view).showToastMessage("Operator and Engineer signature required")
}

(不得不假装，因为现在您共享的代码只会将 boolean 值设置为 true)。

您现在正在对类行为进行单元测试，而不是测试该行为的编码方式。例如，现在如果那些 boolean 值被重构为 Int 值。该测试仍然可以通过，无需您触摸它， 这是好事 !

或者，如果您的代码保持原样。你可以这样测试:

@Test
fun `must show toast message when onValidationSucceeded is called and has not been signature signed`() {
    // Given
    // We haven't signature signed (see verify)
   `when`(app.getString(R.string.quality_control_signatures_not_complete)).thenReturn("Operator and Engineer signature required")
    // When
    presenter.onValidationSucceeded()
    // Then
    verify(view).showToastMessage("Operator and Engineer signature required")
    verify(view, never()).operatorSignatureSigned()
    verify(view, never()).engineerSignatureSigned()
}

如何模拟一个静态方法(提示你不要，你把它移到你系统的边缘，然后再担心它)。

你现在的类(class):

class MyClass {

    override fun signatureSigned(name: String, svgSignature: String, bitmapSignature: Bitmap, signatureType: SignatureType) {
        val svgSignatureGzipped = CompressionTools.gzipCompress(svgSignature)
        ...
    }

}

因此，您需要删除静态调用，以获取另一个可以将静态调用作为依赖项的类。

interface SignatureCompressor {
    fun compress(signature: String)
}

class GZipSignatureCompressor : SignatureCompressor {
    override fun compress(signature: String) {
        return CompressionTools.gzipCompress(signature)
    } 
}

现在你的类(class)变成:

class MyClass(private val compressor: SignatureCompressor) {

    override fun signatureSigned(name: String, svgSignature: String, bitmapSignature: Bitmap, signatureType: SignatureType) {
        val svgSignatureGzipped = compressor.compress(svgSignature)
        ...
    }

}

你可以模拟压缩机:

 val cut = MyClass(mockk())

如果您只有一种压缩 的实现，您也不需要该接口(interface)。