包引入
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
断言
assertEquals("failure - strings are not equal", "text", "text");
assertArrayEquals("failure - byte arrays not same", expected, actual);
assertTrue("failure - should be true", true);
assertFalse("failure - should be false", false);
assertNull("should be null", null);
assertNotNull("should not be null", new Object());
assertSame("should be same", aNumber, aNumber);
assertNotSame("should not be same Object", new Object(), new Object());
Assume(假设)
Assume顾名思义是假设的意思也就是做一些假设，只有当假设成功后才会执行接下来的代码
使用Assumptions类中的假设方法时，当假设不成立时会报错，但是测试会显示被ignore忽略执行。也就是当我们一个类中有多个测试方法时，其中一个假设测试方法假设失败，其他的测试方法全部成功，那么该测试类也会显示测试成功！ 这说明假设方法适用于：在不影响测试是否成功的结果的情况下根据不同情况执行相关代码！
看一下示例：
@Test
public void next() {
assumeTrue(false);
}
执行结果
org.junit.AssumptionViolatedException: got: <false>, expected: is <true>
at com.meituan.meishi.filter.module.JunitTest.next(JunitTest.java:13)
Process finished with exit code 0
注意第一行：exit code 0,说明测试是通过的。
其api不再介绍，和assert完全一样。
AssertThat&Matchers
assertThat([value], [matcher statement]);
以下仅介绍一些常用的Matcher,更详细的API见：http://hamcrest.org/JavaHamcrest/javadoc/2.1/
多Macher
assertThat("myValue", allOf(startsWith("my"), containsString("Val")))//allof
assertThat("myValue", anyOf(startsWith("foo"), containsString("Val")))//anyof
assertThat("fab", both(containsString("a")).and(containsString("b")))//both
assertThat("fan", either(containsString("a")).and(containsString("b")))//attention：either...and
describedAs("a big decimal equal to %0", equalTo(myBigDecimal), myBigDecimal.toPlainString())//没看懂干啥用的
集合（Iterable)
assertThat(Arrays.asList("bar", "baz"), everyItem(startsWith("ba")))//everyItem
assertThat(Arrays.asList("foo", "bar"), hasItem(startsWith("ba")))//hasItem
assertThat(Arrays.asList("foo", "bar", "baz"), hasItems("baz", "foo"))//hasItems
对象（Object)
assertThat(cheese, is(smelly))// is:cheese.equals(smelly)
assertThat(cheese, is(Cheddar.class))//is:instanceof
assertThat(cheese, isA(Cheddar.class))//isA:instanceof
assertThat(cheese, is(not(smelly)))//not:~is
assertThat(null, nullValue());//nullValue
assertThat(null, notNullValue());//notNullValue
assertThat("", theInstance(""));//同sameInstance
assertThat(a, sameInstance(a));//同一个对象
String
assertThat("myStringOfNote", containsString("ring"))//containsString
assertThat("myStringOfNote", startsWith("my"))//endWith
assertThat("myStringOfNote", endsWith("Note"))//startWith
异常
expected
@Test(expected = IndexOutOfBoundsException.class)
public void testException() {
Lists.newArrayList().get(0);
}
try-catch
@Test
public void testException() {
try {
Lists.newArrayList().get(0);
fail("Unexpected: IndexOutboundException should be thrown");
} catch (Exception e) {
assertThat(e.getMessage(), is("Index: 0, Size: 0"));
}
}
@Rule
@Rule
public ExpectedException thrown = ExpectedException.none();
@Test
public void testException() {
thrown.expect(IndexOutOfBoundsException.class);
thrown.expectMessage("Index: 0, Size: 0");
thrown.expectMessage(CoreMatchers.containsString("Size: 0"));//使用Matcher
Lists.newArrayList().get(0);
}
* <ul>
* <li>{@link ErrorCollector}: collect multiple errors in one test method</li>
* <li>{@link ExpectedException}: make flexible assertions about thrown exceptions</li>
* <li>{@link ExternalResource}: start and stop a server, for example</li>
* <li>{@link TemporaryFolder}: create fresh files, and delete after test</li>
* <li>{@link TestName}: remember the test name for use during the method</li>
* <li>{@link TestWatcher}: add logic at events during method execution</li>
* <li>{@link Timeout}: cause test to fail after a set time</li>
* <li>{@link Verifier}: fail test if object state ends up incorrect</li>
* </ul>
*
rule详细介绍：https://github.com/junit-team/junit4/wiki/Rules
@Ignore
@Ignore("Test is ignored as a demonstration")
@Test
public void testSame() {
assertThat(1, is(1));
}
@TimeOut
测试运行时间
@Test(timeout=1000)
public void testWithTimeout() {
...
}
@Theory
@RunWith(Theories.class)
public class UserTest {
@DataPoint
public static String GOOD_USERNAME = "optimus";
@DataPoint
public static String USERNAME_WITH_SLASH = "optimus/prime";
@Theory
public void filenameIncludesUsername(String username) {
assumeThat(username, not(containsString("/")));
assertThat(new User(username).configFileName(), containsString(username));
}
}
测试会执行所有的DataPoint， 如果任意一个assume失败，则该测试会被Ignore；任一 assert失败，则测试用例失败。
参数化测试
@RunWith(ParameParameterizedterized.class)
public class Junit4Test {
@Parameterized.Parameters
public static Collection<Object[]> data() {
return Arrays.asList(new Object[][] {
{ 0, 0 }, { 1, 1 }, { 2, 2}
});
}
@Parameterized.Parameter(0)
public int p1;
@Parameterized.Parameter(1)
public int p2;
@Test
public void testMatcher() {
assertEquals(p1, p2);
}
}
Junit5参数化测试更加简洁，后面再介绍
顺序执行
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class Junit4Test {
@Test
public void testC() {
System.out.println("C");
}
@Test
public void testA() {
System.out.println("A");
}
@Test
public void testB() {
System.out.println("B");
}
}
A
B
C
MethodSorters有三个成员：
-
NAME_ASCENDING:
-
JVM:虚拟机运行的顺序，每次顺序都有可能不同
-
DEFAULT:按照某种确定但不可预测的顺序
Suite&Category
这两个组件是用来对多个TestClass进行组合或者分类测试；可以用在对单个module的归类上。
public class A {
@Test
public void a() {
fail();
}
@Category(SlowTests.class)
@Test
public void b() {
}
}
@Category({SlowTests.class, FastTests.class})
public class B {
@Test
public void c() {
}
}
@RunWith(Categories.class)
@IncludeCategory(SlowTests.class)
@SuiteClasses( { A.class, B.class }) // Note that Categories is a kind of Suite
public class SlowTestSuite {
// Will run A.b and B.c, but not A.a
}
@RunWith(Categories.class)
@IncludeCategory(SlowTests.class)
@ExcludeCategory(FastTests.class)
@SuiteClasses( { A.class, B.class }) // Note that Categories is a kind of Suite
public class SlowTestSuite {
// Will run A.b, but not A.a or B.c
}
Runners
-
代码行运行
org.junit.runner.JUnitCore.runClasses(TestClass1.class, ...); -
命令行运行
java org.junit.runner.JUnitCore TestClass1 [...other test classes...] -
Runners
-
Suite
-
Categories
-
Parameterized
....
-
-
第三方Runner
......
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