JUnit 4使用小结

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/
2. Wiki
   https://code.google.com/archive/p/hamcrest/wikis/Tutorial.wiki