使用 junit 和 mockito 对 AmazonS3 中的 getObject 方法进行单元测试

Question

我有使用 s3.getObject 获取 S3Object 并将对象的内容写入临时文件的方法

@Override
    public Optional<String> getObject(String s3BucketName, String s3Path) {
        try {
            S3Object s3Object = s3Client.getObject(new GetObjectRequest(s3BucketName, s3Path));
            try (S3ObjectInputStream s3ObjectInputStream = s3Object.getObjectContent()){
                File tmp = File.createTempFile("/tmp/" + UUID.randomUUID().toString(), ".json");
                IOUtils.copy(s3ObjectInputStream, new FileOutputStream(tmp));
                return Optional.of(tmp.getAbsolutePath());
            } catch (Exception e) {
                System.err.println(e.getMessage());
            }
        } catch (AmazonServiceException e) {
            String msg = String.format("Service error while getting object=%s in bucket=%s",
                    s3Path, s3BucketName);
            throw new RuntimeException(msg, e);
        } catch (SdkClientException e) {
            String msg = String.format("Client error while getting object=%s in bucket=%s",
                    s3Path, s3BucketName);
            throw new RuntimeException(msg + e.getMessage());
        }
        return Optional.empty();
    }

我不确定我是否了解如何为此方法编写单元测试。这是我试过的

@Test
    public void getObjectTest() throws UnsupportedEncodingException {
        S3Object s3Object = Mockito.mock(S3Object.class);
        s3Object.setObjectContent(new StringInputStream(TEST_STRING));
        Mockito.when(mockS3Client.getObject(new GetObjectRequest(TEST_S3BUCKET, TEST_S3OBJECT))).thenReturn(s3Object);
        s3Accessor.getObject(TEST_S3BUCKET, TEST_S3OBJECT);
        verify(mockS3Client).getObject(new GetObjectRequest(TEST_S3BUCKET, TEST_S3OBJECT));
    }

我是单元测试的新手，我不确定我可以在这里断言什么，因为我从该方法中只获得了文件的绝对路径。有人可以就此给我建议吗？

Answer 1

我建议在测试中更改一些内容不要模拟 S3Object 而是从本地文件构建对象，将值设置为模拟对象是不正确的。

您还应该添加异常测试。

查看下面的代码

import com.amazonaws.AmazonServiceException;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.UnsupportedEncodingException;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThrows;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

@RunWith(MockitoJUnitRunner.class)
public class ExampleServiceTest {

    @Mock
    private AmazonS3Client mockS3Client;

    @Test
    public void getObjectTest() throws UnsupportedEncodingException, FileNotFoundException {
        String testBucketName = "test_bucket", s3Path = "/files/A.json";
        S3Object s3Object = buildS3Object();
        when(mockS3Client.getObject(new GetObjectRequest(testBucketName, s3Path))).thenReturn(s3Object);
        ExampleService exampleService = new ExampleService(mockS3Client);

        exampleService.getObject(testBucketName, s3Path);

        verify(mockS3Client).getObject(new GetObjectRequest(testBucketName, s3Path));
    }


    @Test
    public void ShouldThrowRuntimeExceptionServiceErrorMessageWhenAmazonServiceException() throws FileNotFoundException {
        String testBucketName = "test_bucket", s3Path = "/files/A.json";

        when(mockS3Client.getObject(new GetObjectRequest(testBucketName, s3Path))).thenThrow(AmazonServiceException.class);
        ExampleService exampleService = new ExampleService(mockS3Client);

        Exception exception = assertThrows(RuntimeException.class, () -> {
            exampleService.getObject(testBucketName, s3Path);
        });

        assertEquals("Service error while getting object=/files/A.json in bucket=test_bucket", exception.getMessage());
    }

    private S3Object buildS3Object() throws FileNotFoundException {
        S3Object s3Object = new S3Object();
        s3Object.setObjectContent(new FileInputStream("your_path/src/test/resources/A.json"));
        return s3Object;
    }
}

使用 junit 和 mockito 对 AmazonS3 中的 getObject 方法进行单元测试

Unit test using junit and mockito for getObject method in AmazonS3

java

junit

unit-testing

mockito