JUnit 4使用小结

╰+攻爆jí腚メ 2022-05-14 00:10 77阅读 0赞

## JUnit ##

JUnit是Java开发中必备的单元测试工具，目前手里使用的JUnit 4.

## Hamcrest ##

hamcrest使用的断言功能，maven依赖定义如下：

<dependency>
              <groupId>org.hamcrest</groupId>
              <artifactId>hamcrest-junit</artifactId>
              <version>2.0.0.0</version>
              <scope>test</scope>
        </dependency>

## 常用的标注 ##

@Before: 在每个Test方法之前执行  
@After 在每个Test方法执行之后  
@BefroreClass 在每个测试类启动之前  
@AfterClass 在每个测试类启动之后。  
@Ignore 忽略当前测试类  
@Test 将当前方法进行测试  
(expected=xxxException.class) 期待的异常  
(timeout=xx) 超时时间

## AssertThat ##

assertThat的判断逻辑，在自于hamcrest。其中常用的方法如下：

assertThat( n, allOf( greaterThan(1), lessThan(15) ) );
    assertThat( n, anyOf( greaterThan(16), lessThan(8) ) );
    assertThat( n, anything() );
    assertThat( str, is( "bjsxt" ) );
    assertThat( str, not( "bjxxt" ) );
    
    assertThat( str, containsString( "bjsxt" ) );
    assertThat( str, endsWith("bjsxt" ) ); 
    assertThat( str, startsWith( "bjsxt" ) ); 
    assertThat( n, equalTo( nExpected ) ); 
    assertThat( str, equalToIgnoringCase( "bjsxt" ) ); 
    assertThat( str, equalToIgnoringWhiteSpace( "bjsxt" ) );
    
    assertThat( d, closeTo( 3.0, 0.3 ) );
    assertThat( d, greaterThan(3.0) );
    assertThat( d, lessThan (10.0) );
    assertThat( d, greaterThanOrEqualTo (5.0) );
    assertThat( d, lessThanOrEqualTo (16.0) );
    
    assertThat( map, hasEntry( "bjsxt", "bjsxt" ) );
    assertThat( iterable, hasItem ( "bjsxt" ) );
    assertThat( map, hasKey ( "bjsxt" ) );
    assertThat( map, hasValue ( "bjsxt" ) );

## JUnit中的assert ##

在JUnit中也提供了类似的断言：

assertTrue
    assertEquals

## 代码示例 ##

被测试类：

public class Price {
        public int add(int num1, int num2) {
            return num1 + num2;
        }
    }

单元测试方法：

import static org.hamcrest.CoreMatchers.equalTo;
    import static org.hamcrest.CoreMatchers.is;
    import static org.junit.Assert.assertEquals;
    import static org.junit.Assert.assertThat;
    import static org.junit.Assert.assertTrue;
    
    import org.junit.After;
    import org.junit.Before;
    import org.junit.Test;
    
    public class PriceTest { 
        @Before
        public void setUp() throws Exception {
        }
    
        @After
        public void tearDown() throws Exception {
        }
    
        @Test
        public void testAdd() {
            int result = new Price().add(12, 21);
    
            assertEquals(33, result);
            assertTrue(result == 33);
        }
    
        @Test
        public void testAddThat() {
            int result = new Price().add(12, 21);
    
            assertThat(result, is(33));
            assertThat("Invalid Result", result, equalTo(33));
        }
    }

## 参考资料 ##

1.  Hamcrest API  
    [http://hamcrest.org/JavaHamcrest/javadoc/2.0.0.0/][http_hamcrest.org_JavaHamcrest_javadoc_2.0.0.0]
2.  Wiki  
    [https://code.google.com/archive/p/hamcrest/wikis/Tutorial.wiki][https_code.google.com_archive_p_hamcrest_wikis_Tutorial.wiki]

[http_hamcrest.org_JavaHamcrest_javadoc_2.0.0.0]: http://hamcrest.org/JavaHamcrest/javadoc/2.0.0.0/
[https_code.google.com_archive_p_hamcrest_wikis_Tutorial.wiki]: https://code.google.com/archive/p/hamcrest/wikis/Tutorial.wiki