JUnit4---Hamcrest匹配器常用方法总结

一.Hamcrest是什么？

Hamcrest is a library of matchers, which can be combined in to create flexible expressions of intent in tests.

Hamcrest 是一个为了测试为目的，且能组合成灵活表达式的匹配器类库。

二.Hamcrest jar包

• hamcrest-core.jar -- This is the core API to be used by third-party framework providers. This includes the a foundation set of matcher implementations for common operations. This API is stable and will rarely change. You will
  need this library as a minimum.
• hamcrest-library.jar -- The ever-growing library of Matcher implementations. This will grow between releases.
• hamcrest-generator.jar -- A tool to allow many Matcher implementations to be combined into a single class so users don't have to remember many classes/packages to import. Generates code.
• hamcrest-integration.jar -- Provides integration between Hamcrest and other testing tools, including JUnit (3 and 4), TestNG, jMock and EasyMock.

Alternatively, if you don't care:

• hamcrest-all.jar -- Includes all of the above.

三.常用方法介绍

一般，在项目中导入hamcrest-core.jar， hamcrest-library.jar就能满足使用。

Eclipse新建一个JUnit test case； 测试类导入

import static org.hamcrest.Matchers.*;

测试方法如下：

    @Test





    public void testHamcrestMatchers() {





        // 核心匹配





        // allOf: 所有条件都必须满足，相当于&&





        assertThat("myname", allOf(startsWith("my"), containsString("name")));





        // anyOf: 其中一个满足就通过， 相当于||





        assertThat("myname", anyOf(startsWith("na"), containsString("name")));





        // both: &&





        assertThat("myname", both(containsString("my")).and(containsString("me")));





        // either: 两者之一





        assertThat("myname", either(containsString("my")).or(containsString("you")));





        // everyItem: 每个元素都需满足特定条件





        assertThat(Arrays.asList("my", "mine"), everyItem(startsWith("m")));





        // hasItem: 是否有这个元素





        assertThat(Arrays.asList("my", "mine"), hasItem("my"));





        // hasItems: 包含多个元素





        assertThat(Arrays.asList("my", "mine", "your"), hasItems("your", "my"));





        // is: is(equalTo(x))或is(instanceOf(clazz.class))的简写





        assertThat("myname", is("myname"));





        assertThat("mynmae", is(String.class));





        // anything(): 任何情况下，都匹配正确





        assertThat("myname", anything());





        // not: 否为真，相当于！





        assertThat("myname", is(not("you")));





        // nullValue(): 值为空





        String str = null;





        assertThat(str, is(nullValue()));





        // notNullValue(): 值不为空





        String str2 = "123";





        assertThat(str2, is(notNullValue()));





 





        





        // 字符串匹配





        // containsString：包含字符串





        assertThat("myname", containsString("na"));





        // stringContainsInOrder: 顺序包含，“my”必须在“me”前面





        assertThat("myname", stringContainsInOrder(Arrays.asList("my", "me")));





        // endsWith: 后缀





        assertThat("myname", endsWith("me"));





        // startsWith: 前缀





        assertThat("myname", startsWith("my"));





        // isEmptyString(): 空字符串





        assertThat("", isEmptyString());





        // equalTo: 值相等， Object.equals(Object)





        assertThat("myname", equalTo("myname"));





        assertThat(new String[] {"a", "b"}, equalTo(new String[] {"a", "b"}));





        // equalToIgnoringCase: 比较时，忽略大小写





        assertThat("myname", equalToIgnoringCase("MYNAME"));





        // equalToIgnoringWhiteSpace: 比较时， 首尾空格忽略， 比较时中间用单个空格





        assertThat(" my \t name ", equalToIgnoringWhiteSpace(" my name "));





        // isOneOf: 是否为其中之一





        assertThat("myname", isOneOf("myname", "yourname"));





        // isIn: 是否为其成员





        assertThat("myname", isIn(new String[]{"myname", "yourname"}));





        // toString() 返回值校验





        assertThat(333, hasToString(equalTo("333")));





       





        





        // 数值匹配





        // closeTo: [operand-error, operand+error], Double或BigDecimal类型





        assertThat(3.14, closeTo(3, 0.5));





        assertThat(new BigDecimal("3.14"), is(closeTo(new BigDecimal("3"), new BigDecimal("0.5"))));





        // comparesEqualTo: compareTo比较值





        assertThat(2, comparesEqualTo(2));





        // greaterThan： 大于





        assertThat(2, greaterThan(0));





        // greaterThanOrEqualTo: 大于等于





        assertThat(2, greaterThanOrEqualTo(2));





        // lessThan: 小于





        assertThat(0, lessThan(2));





        // lessThanOrEqualTo: 小于等于





        assertThat(0, lessThanOrEqualTo(0));





        





        





        





        // 集合匹配





        // array: 数组长度相等且对应元素也相等





        assertThat(new Integer[]{1, 2, 3}, is(array(equalTo(1), equalTo(2), equalTo(3))));





        // hasItemInArray: 数组是否包含特定元素





        assertThat(new String[]{"my", "you"}, hasItemInArray(startsWith("y")));





        // arrayContainingInAnyOrder， 顺序无关，长度要一致





        assertThat(new String[]{"my", "you"}, arrayContainingInAnyOrder("you", "my"));





        // arrayContaining:  顺序，长度一致





        assertThat(new String[]{"my", "you"}, arrayContaining("my", "you"));





        // arrayWithSize: 数组长度





        assertThat(new String[]{"my", "you"}, arrayWithSize(2));





        // emptyArray: 空数组





        assertThat(new String[0], emptyArray());





        // hasSize: 集合大小





        assertThat(Arrays.asList("my", "you"), hasSize(equalTo(2)));





        // empty: 空集合





        assertThat(new ArrayList<String>(), is(empty()));





        // isIn: 是否为集合成员





        assertThat("myname", isIn(Arrays.asList("myname", "yourname")));





       // Map匹配





        Map<String, String> myMap = new HashMap<String, String>();





        myMap.put("name", "john");





        // hasEntry: key && value匹配





        assertThat(myMap, hasEntry("name", "john"));





        // hasKey: key匹配





        assertThat(myMap, hasKey(equalTo("name")));





        // hasValue: value匹配





        assertThat(myMap, hasValue(equalTo("john")));





    }

原文地址：https://blog.csdn.net/neven7/article/details/42489723