静态方法 单元测试 springboot+mokito+junit5

CodecUtils的方法是静态类，使用@InjectMocks不能有用，因为这个注解只能用于非静态的对象。

想要为静态方法写单元测试，可以使用Mockito.mockStatic(Class classToMock)方法，它可以返回一个MockedStatic对象，用于模拟静态方法的调用。

1.导入依赖

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><version>2.1.18.RELEASE</version><scope>test</scope><exclusions><exclusion><groupId>org.mockito</groupId><artifactId>mockito-core</artifactId></exclusion></exclusions></dependency><dependency><groupId>org.mockito</groupId><artifactId>mockito-junit-jupiter</artifactId><version>5.3.1</version><scope>test</scope></dependency><dependency><groupId>org.mockito</groupId><artifactId>mockito-core</artifactId><version>4.1.0</version><scope>test</scope></dependency><dependency><groupId>org.mockito</groupId><artifactId>mockito-inline</artifactId><version>4.1.0</version><scope>test</scope></dependency>

2.单元测试

importorg.junit.jupiter.api.Test;importorg.mockito.MockedStatic;importorg.mockito.Mockito;importstaticorg.junit.jupiter.api.Assertions.*;importstaticorg.mockito.Mockito.*;classCodecUtilsTest{@TestvoidtestBytesToBinary(){byte[] bytes ={1,2,3};String expected ="000000010000001000000011";try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.bytesToBinary(bytes)).thenReturn(expected);String actual =CodecUtils.bytesToBinary(bytes);assertEquals(expected, actual);
            mocked.verify(()->CodecUtils.bytesToBinary(bytes));}}@TestvoidtestBinaryToBytes(){String binary ="000000010000001000000011";byte[] expected ={1,2,3};try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.binaryToBytes(binary)).thenReturn(expected);byte[] actual =CodecUtils.binaryToBytes(binary);assertArrayEquals(expected, actual);
            mocked.verify(()->CodecUtils.binaryToBytes(binary));}}@TestvoidtestBytesToHex(){byte[] bytes ={1,2,3};String expected ="010203";try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.bytesToHex(bytes)).thenReturn(expected);String actual =CodecUtils.bytesToHex(bytes);assertEquals(expected, actual);
            mocked.verify(()->CodecUtils.bytesToHex(bytes));}}@TestvoidtestHexToBytes()throwsException{String hex ="010203";byte[] expected ={1,2,3};try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.hexToBytes(hex)).thenReturn(expected);byte[] actual =CodecUtils.hexToBytes(hex);assertArrayEquals(expected, actual);
            mocked.verify(()->CodecUtils.hexToBytes(hex));}}@TestvoidtestBytesToDecimal(){byte[] bytes ={1,2,3};String expected ="66051";try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.bytesToDecimal(bytes)).thenReturn(expected);String actual =CodecUtils.bytesToDecimal(bytes);assertEquals(expected, actual);
            mocked.verify(()->CodecUtils.bytesToDecimal(bytes));}}@TestvoidtestDecimalToBytes(){String decimal ="66051";byte[] expected ={1,2,3};try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.decimalToBytes(decimal)).thenReturn(expected);byte[] actual =CodecUtils.decimalToBytes(decimal);assertArrayEquals(expected, actual);
            mocked.verify(()->CodecUtils.decimalToBytes(decimal));}}@TestvoidtestBytesToAscii(){byte[] bytes ={65,66,67};String expected ="ABC";try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.bytesToAscii(bytes)).thenReturn(expected);String actual =CodecUtils.bytesToAscii(bytes);assertEquals(expected, actual);
            mocked.verify(()->CodecUtils.bytesToAscii(bytes));}}@TestvoidtestAsciiToBytes(){String ascii ="ABC";byte[] expected ={65,66,67};try(MockedStatic<CodecUtils> mocked =Mockito.mockStatic(CodecUtils.class)){
            mocked.when(()->CodecUtils.asciiToBytes(ascii)).thenReturn(expected);byte[] actual =CodecUtils.asciiToBytes(ascii);assertArrayEquals(expected, actual);
            mocked.verify(()->CodecUtils.asciiToBytes(ascii));}}}

可以参考如下地址，了解如何使用Mockito.mockStatic方法。
① Mocking Static Methods With Mockito | Baeldung.
另外，可以使用PowerMockito工具来模拟静态方法，但是它需要额外的配置和依赖。可以查看如下回答。
② java - Mockito InjectMocks into static object - Stack Overflow.
③ unit testing - Java Mockito inject a static class - Stack Overflow.