JUnit tutorial (2)

Ii. Core-Assertions

Assertions are the core implementation method for writing test cases, that is, the expected value and test result, to determine whether the test is successful.

1. Core assertion method

Assertarrayequals (expecteds, actuals)	Check whether the two arrays are equal.
Assertequals (expected, actual)	Check whether two objects are equal. Similar to the equals () method used for string comparison
Assertnotequals (first, second)	Check whether the two objects are not equal.
Assertnull (object)	Check whether the object is empty.
Assertnotnull (object)	Check whether the object is not empty.
Assertsame (expected, actual)	Check whether the references of the two objects are equal. Similar to comparing two objects with "="
Assertnotsame (unexpected, actual)	Check whether the references of the two objects are not equal. Similar to = "Compares two objects
Asserttrue (condition)	Check whether the running result is true.
Assertfalse (condition)	Check whether the running result is false.
Assertthat (actual, matcher)	Check whether the actual value meets the specified conditions.
Fail ()	Failed test

2. Example

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())));  }}

Iii. Core-Comment

1. Description

@ Before	Initialization Method
@ After	Release resources
@ Test	Test method. Here we can test the expected exception and timeout.
@ Ignore	Test method ignored
@ Beforeclass	All tests are executed only once and must be static void
@ Afterclass	All tests are executed only once and must be static void
@ Runwith	Specify a runner for the test class
@ Parameters	Test data set of the specified test class
@ Rule	Allow flexible addition or redefinition of the behavior of each test method in the test class
@ Fixmethodorder	Specify the execution sequence of the test method

2. execution sequence

The execution sequence of a test unit test is:

@ Beforeclass-> @ before-> @ test-> @ After-> @ afterclass

The call sequence of each test method is as follows:

@ Before-> @ test-> @ after

3. Example

package test;import static org.junit.Assert.*;import org.junit.*;public class JDemoTest {@BeforeClasspublic static void setUpBeforeClass() throws Exception {System.out.println("in BeforeClass================");}@AfterClasspublic static void tearDownAfterClass() throws Exception {System.out.println("in AfterClass=================");}@Beforepublic void before() {System.out.println("in Before");}@Afterpublic 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");}@Testpublic void testdivision() {JDemo a = new JDemo();assertEquals(3, a.division(6, 2));System.out.println("in Test ----Division");}@Ignore@Testpublic void test_ignore() {JDemo a = new JDemo();assertEquals(6, a.add(1, 5));System.out.println("in test_ignore");}@Testpublic 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;}}

Execution result:

in BeforeClass================in Beforein Test ----Addin Afterin Beforein Test ----Divisionin Afterin AfterClass=================

 

In the upper-left red box in the figure, the result of running JUnit is displayed. Five are successful (one is ignored), one is incorrect, and one is failed. (Note that errors and failures are not the same. errors indicate code errors. Failure indicates that the test method fails)

In the lower-left red box, the running status of each test method is displayed. The icons for success, error, failure, and failure are different, and the running time is displayed.

The right part is the exception stack. You can view the exception information.

 

In the next article, we will provide more examples and continue to introduce JUnit.