莫基托 | JUnit | Avro：模擬 void 方法不起作用

Question

我寫了一個avro序列化的方法，我想測試一下。

方法

@SneakyThrows
@Override
public byte[] serialize(String topic, T data) {
    try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
        writeSerializedAvro(stream, data, data.getSchema());
        return stream.toByteArray();
    } catch (IOException e) {
        throw new AvroSerializationException(e.getMessage(), e);
    }
}

private void writeSerializedAvro(ByteArrayOutputStream stream, T data, Schema schema) throws IOException {
    binaryEncoder = EncoderFactory.get().binaryEncoder(stream, binaryEncoder);
    DatumWriter<T> datumWriter = new GenericDatumWriter<>(schema);
    datumWriter.write(data, binaryEncoder);
    binaryEncoder.flush();
}

datumWriter.write或binaryEncoder.flush()可以拋出IOException 。

在測試中，我想看看是否IOException ，我的方法捕獲它並將其包裝在AvroSerializationException （我編寫的一個類）中。

單元測試

    @Test(expected = AvroSerializationException.class)
public void testSerializeException() throws IOException {
    // Given 
// need to mock here

    // When
    serializer.serialize("", avroObject);
}

我曾嘗試使用doThrow().when()方法doThrow().when() GenericDatumWriter 、 BufferedBinaryEncoder和EncoderFactory ，但沒有任何效果對我doThrow().when() 。

BufferedBinaryEncoder binaryEncoder = Mockito.mock(BufferedBinaryEncoder.class);
Mockito.doThrow(new IOException()).when(binaryEncoder).flush();

和

    GenericDatumWriter datumWriter = Mockito.mock(GenericDatumWriter.class);
    Mockito.doThrow(new IOException()).when(datumWriter).write(any(), any());

但是，問題又回到了，我應該如何將這些對象傳遞給我的序列化程序，同時牢記最佳實踐？

Answer 1

您需要首先使用 Mockito 模擬對象並在您的類中使用它，然后將拋出異常，如下所示：

您的代碼：

private DatumWriter<T> datumWriter = new GenericDatumWriter<>(schema);

@SneakyThrows
@Override
public byte[] serialize(String topic, T data) {
    try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
        writeSerializedAvro(stream, data, data.getSchema());
        return stream.toByteArray();
    } catch (IOException e) {
        throw new AvroSerializationException(e.getMessage(), e);
    }
}

private void writeSerializedAvro(ByteArrayOutputStream stream, T data, Schema schema) throws IOException {
    binaryEncoder = EncoderFactory.get().binaryEncoder(stream, binaryEncoder);
    datumWriter.write(data, binaryEncoder);
    binaryEncoder.flush();
}

public void setDatumWriter (DatumWriter datumWriter){
   this.datumWriter=datumWriter;
}

您的測試代碼：

@Test(expected = AvroSerializationException.class)
public void testSerializeException() throws IOException {
    // Given 
    DatumWriter<YourClass> datumWriter = Mockito.mock(DatumWriter<YourClass>.class);
    when(datumWriter.write(anyObject(), anyObject())).thenThrow(IOException.class);
    
    serializer.setDatumWriter(datumWriter);  
   
    serializer.serialize("", avroObject);
}