JUnit使用

二、核心——斷言

斷言是編寫測試用例的核心實現方式，即期望值是多少，測試的結果是多少，以此來判斷測試是否通過。

1. 斷言核心方法

assertArrayEquals(expecteds, actuals)	查看兩個數組是否相等。
assertEquals(expected, actual)	查看兩個對象是否相等。類似於字符串比較使用的equals()方法
assertNotEquals(first, second)	查看兩個對象是否不相等。
assertNull(object)	查看對象是否爲空。
assertNotNull(object)	查看對象是否不爲空。
assertSame(expected, actual)	查看兩個對象的引用是否相等。類似於使用“==”比較兩個對象
assertNotSame(unexpected, actual)	查看兩個對象的引用是否不相等。類似於使用“!=”比較兩個對象
assertTrue(condition)	查看運行結果是否爲true。
assertFalse(condition)	查看運行結果是否爲false。
assertThat(actual, matcher)	查看實際值是否滿足指定的條件
fail()	讓測試失敗

2. 示例

package test;

import static org.hamcrest.CoreMatchers.*;
import static org.junit.Assert.*;

import java.util.Arrays;

import org.hamcrest.core.CombinableMatcher;
import org.junit.Test;

public class AssertTests {

      @Test
      public void testAssertArrayEquals() {
        byte[] expected = "trial".getBytes();
        byte[] actual = "trial".getBytes();
        org.junit.Assert.assertArrayEquals("failure - byte arrays not same", expected, actual);
      }

      @Test
      public void testAssertEquals() {
        org.junit.Assert.assertEquals("failure - strings not same", 5l, 5l);
      }

      @Test
      public void testAssertFalse() {
        org.junit.Assert.assertFalse("failure - should be false", false);
      }

      @Test
      public void testAssertNotNull() {
        org.junit.Assert.assertNotNull("should not be null", new Object());
      }

      @Test
      public void testAssertNotSame() {
        org.junit.Assert.assertNotSame("should not be same Object", new Object(), new Object());
      }

      @Test
      public void testAssertNull() {
        org.junit.Assert.assertNull("should be null", null);
      }

      @Test
      public void testAssertSame() {
        Integer aNumber = Integer.valueOf(768);
        org.junit.Assert.assertSame("should be same", aNumber, aNumber);
      }

      // JUnit Matchers assertThat
      @Test
      public void testAssertThatBothContainsString() {
        org.junit.Assert.assertThat("albumen", both(containsString("a")).and(containsString("b")));
      }

      @Test
      public void testAssertThathasItemsContainsString() {
        org.junit.Assert.assertThat(Arrays.asList("one", "two", "three"), hasItems("one", "three"));
      }

      @Test
      public void testAssertThatEveryItemContainsString() {
        org.junit.Assert.assertThat(Arrays.asList(new String[] { "fun", "ban", "net" }), everyItem(containsString("n")));
      }

      // Core Hamcrest Matchers with assertThat
      @Test
      public void testAssertThatHamcrestCoreMatchers() {
        assertThat("good", allOf(equalTo("good"), startsWith("good")));
        assertThat("good", not(allOf(equalTo("bad"), equalTo("good"))));
        assertThat("good", anyOf(equalTo("bad"), equalTo("good")));
        assertThat(7, not(CombinableMatcher.<Integer> either(equalTo(3)).or(equalTo(4))));
        assertThat(new Object(), not(sameInstance(new Object())));
      }
}

package test;

import static org.hamcrest.CoreMatchers.*;
import static org.junit.Assert.*;

import java.util.Arrays;

import org.hamcrest.core.CombinableMatcher;
import org.junit.Test;

public class AssertTests {

	  @Test
	  public void testAssertArrayEquals() {
	    byte[] expected = "trial".getBytes();
	    byte[] actual = "trial".getBytes();
	    org.junit.Assert.assertArrayEquals("failure - byte arrays not same", expected, actual);
	  }

	  @Test
	  public void testAssertEquals() {
	    org.junit.Assert.assertEquals("failure - strings not same", 5l, 5l);
	  }

	  @Test
	  public void testAssertFalse() {
	    org.junit.Assert.assertFalse("failure - should be false", false);
	  }

	  @Test
	  public void testAssertNotNull() {
	    org.junit.Assert.assertNotNull("should not be null", new Object());
	  }

	  @Test
	  public void testAssertNotSame() {
	    org.junit.Assert.assertNotSame("should not be same Object", new Object(), new Object());
	  }

	  @Test
	  public void testAssertNull() {
	    org.junit.Assert.assertNull("should be null", null);
	  }

	  @Test
	  public void testAssertSame() {
	    Integer aNumber = Integer.valueOf(768);
	    org.junit.Assert.assertSame("should be same", aNumber, aNumber);
	  }

	  // JUnit Matchers assertThat
	  @Test
	  public void testAssertThatBothContainsString() {
	    org.junit.Assert.assertThat("albumen", both(containsString("a")).and(containsString("b")));
	  }

	  @Test
	  public void testAssertThathasItemsContainsString() {
	    org.junit.Assert.assertThat(Arrays.asList("one", "two", "three"), hasItems("one", "three"));
	  }

	  @Test
	  public void testAssertThatEveryItemContainsString() {
	    org.junit.Assert.assertThat(Arrays.asList(new String[] { "fun", "ban", "net" }), everyItem(containsString("n")));
	  }

	  // Core Hamcrest Matchers with assertThat
	  @Test
	  public void testAssertThatHamcrestCoreMatchers() {
	    assertThat("good", allOf(equalTo("good"), startsWith("good")));
	    assertThat("good", not(allOf(equalTo("bad"), equalTo("good"))));
	    assertThat("good", anyOf(equalTo("bad"), equalTo("good")));
	    assertThat(7, not(CombinableMatcher.<Integer> either(equalTo(3)).or(equalTo(4))));
	    assertThat(new Object(), not(sameInstance(new Object())));
	  }
}

三、核心——註解

1. 說明

@Before	初始化方法
@After	釋放資源
@Test	測試方法，在這裏可以測試期望異常和超時時間
@Ignore	忽略的測試方法
@BeforeClass	針對所有測試，只執行一次，且必須爲static void
@AfterClass	針對所有測試，只執行一次，且必須爲static void
@RunWith	指定測試類使用某個運行器
@Parameters	指定測試類的測試數據集合
@Rule	允許靈活添加或重新定義測試類中的每個測試方法的行爲
@FixMethodOrder	指定測試方法的執行順序

2. 執行順序

一個測試類單元測試的執行順序爲：

@BeforeClass –> @Before –> @Test –> @After –> @AfterClass

每一個測試方法的調用順序爲：

@Before –> @Test –> @After

3. 示例

package test;

import static org.junit.Assert.*;

import org.junit.*;

public class JDemoTest {

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        System.out.println("in BeforeClass================");
    }

    @AfterClass
    public static void tearDownAfterClass() throws Exception {
        System.out.println("in AfterClass=================");
    }

    @Before
    public void before() {
        System.out.println("in Before");
    }

    @After
    public void after() {
        System.out.println("in After");
    }

    @Test(timeout = 10000)
    public void testadd() {
        JDemo a = new JDemo();
        assertEquals(6, a.add(3, 3));
        System.out.println("in Test ----Add");
    }

    @Test
    public void testdivision() {
        JDemo a = new JDemo();
        assertEquals(3, a.division(6, 2));
        System.out.println("in Test ----Division");
    }

    @Ignore
    @Test
    public void test_ignore() {
        JDemo a = new JDemo();
        assertEquals(6, a.add(1, 5));
        System.out.println("in test_ignore");
    }

    @Test
    public void teest_fail() {
        fail();
    }
}

class JDemo extends Thread {

    int result;

    public int add(int a, int b) {
        try {
            sleep(1000);
            result = a + b;
        } catch (InterruptedException e) {
        }
        return result;
    }

    public int division(int a, int b) {
        return result = a / b;
    }
}

package test;

import static org.junit.Assert.*;

import org.junit.*;

public class JDemoTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
		System.out.println("in BeforeClass================");
	}

	@AfterClass
	public static void tearDownAfterClass() throws Exception {
		System.out.println("in AfterClass=================");
	}

	@Before
	public void before() {
		System.out.println("in Before");
	}

	@After
	public void after() {
		System.out.println("in After");
	}

	@Test(timeout = 10000)
	public void testadd() {
		JDemo a = new JDemo();
		assertEquals(6, a.add(3, 3));
		System.out.println("in Test ----Add");
	}

	@Test
	public void testdivision() {
		JDemo a = new JDemo();
		assertEquals(3, a.division(6, 2));
		System.out.println("in Test ----Division");
	}

	@Ignore
	@Test
	public void test_ignore() {
		JDemo a = new JDemo();
		assertEquals(6, a.add(1, 5));
		System.out.println("in test_ignore");
	}

	@Test
	public void teest_fail() {
		fail();
	}
}

class JDemo extends Thread {

	int result;

	public int add(int a, int b) {
		try {
			sleep(1000);
			result = a + b;
		} catch (InterruptedException e) {
		}
		return result;
	}

	public int division(int a, int b) {
		return result = a / b;
	}
}

執行結果：

in BeforeClass================
in Before
in Test ----Add
in After
in Before
in Test ----Division
in After
in AfterClass=================

in BeforeClass================
in Before
in Test ----Add
in After
in Before
in Test ----Division
in After
in AfterClass=================

 

圖中左上紅框中部分表示Junit運行結果，5個成功（1個忽略），1個錯誤，1個失敗。（注意錯誤和失敗不是一回事，錯誤說明代碼有錯誤，而失敗表示該測試方法測試失敗）

左下紅框中則表示出了各個測試方法的運行狀態，可以看到成功、錯誤、失敗、失敗各自的圖標是不一樣的，還可以看到運行時間。

右邊部分則是異常堆棧，可查看異常信息。

 

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