Unit test (II) -- JUnit

As mentioned above Junit yes Java One of the most commonly used testing frameworks in . Let's say Junit4 Examples to illustrate Junit Usage of .

• A basic Junit Test case template ：

package junit;
  
import org.junit.*;
import static org.junit.Assert.*;
import java.util.*;
  
public class SimpleTest {
    
  
    private Collection collection;
     
    @BeforeClass
    public static void oneTimeSetUp() {
    
        // one-time initialization code 
    }
  
    @AfterClass
    public static void oneTimeTearDown() {
    
        // one-time cleanup code
    }
  
    @Before
    public void setUp() {
    
        collection = new ArrayList();
    }
     
    @After
    public void tearDown() {
    
        collection.clear();
    }
  
    @Test
    public void testEmptyCollection() {
    
        assertTrue(collection.isEmpty());
    }
     
    @Test
    public void testOneItemCollection() {
    
        collection.add("itemA");
        assertEquals(1, collection.size());
    }
}

• Junit Commonly used annotations

（1）@org.junit.Test

Mark this is a test method .Junit An instance of this test class will be constructed first , Then call the test method .

@Test Comments provide 2 Parameters :

​ a. “expected”, Define the exceptions that the test method should throw , If the test method does not throw an exception or throws a different exception , Test to fail .

​ b.“timeout”, If the test runs longer than the defined time , Test to fail （ Unit is millisecond ）

（2）@org.junit.BeforeClass

All unit test methods Execute the method with this annotation before execution , If the parent class inherited by the current unit test class also has a @BeforeClass Method of annotation , Then execute @BeforeClass Method of annotation , Then execute the subclass with @BeforeClass The method of annotation is annotated in public static void No parameter method

（3）@org.junit.AfterClass

All unit test methods After execution, execute the method with this annotation again , If the parent class inherited by the current unit test class also has a @AfterClass Method of annotation , Then execute the band in the subclass first @AfterClass Method of annotation , Then execute the parent class with @AfterClass Method of annotation , Be careful , If the belt @Before Method of annotation , belt @AfterClass The annotation method will certainly be implemented , Even with @BeforeClass Error in annotation method , It will also execute belt @AfterClass Method of annotation . in other words , If the belt @BeforeClass Method of annotation , Then the belt will be executed @AfterClass Method of annotation . Annotations in public static void No parameter method

（4）@org.junit.Before

Each unit test method The method with this annotation will be executed before execution , If the parent class inherited by the current unit test class also has a Before Method of annotation , Then execute the band in the parent class first @Before Method of annotation , Then execute the subclass with @Before Method of annotation Annotations in public void On the way

**（5）@org.junit.After **

After each unit test method is executed, the method with this annotation will be executed . If the parent class inherited by the current unit test class also has a After Method of annotation , Then execute the band in the subclass first @After Method of annotation , Then execute the parent class with @After Method of annotation , Be careful , If the belt @Before Method of annotation , belt @After The annotation method will certainly be implemented , Even if the test method or @Before Method error reporting , It will also execute belt @After Method of annotation . Of course , If you are taking @BeforeClass There is an error in the annotation method , Or it reports an error in the construction method , Then the belt will definitely not be executed @After Method of annotation .
in other words , If the belt @Before Method of annotation , Then the belt will be executed @After Method of annotation . Annotations in public void On the way
（6）@org.junit.Ignore
Configure on the test method , Then this test method will not be executed , Configure on the test class , Then all test methods of this test class will not be executed

• Junit Assertion
  
• Junit Execution order

have access to **@FixMethodOrder** You can specify the execution order of unit test methods , The accepted parameter value is ：

MethodSorters.NAME_ASCENDING： By method name Alphabetical order Sort

MethodSorters.DEFAULT： By method name HashCode value Sequential execution . If the method name is HashCode Value consistent , Then follow MethodSorters.NAME_ASCENDING Sort .

MethodSorters.JVML： according to JVM The way to get it Sequential execution .

It's usually used MethodSorters.NAME_ASCENDING, That is, execute in the parent order of method names . The execution order of the final test class in the other two methods is actually unpredictable .

package junit;
  
import org.junit.*;
import static org.junit.Assert.*;
import java.util.*;
 
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class SimpleTest {
    
    @Test
    public void testEmptyCollection() {
    
        assertTrue(collection.isEmpty());
    }
     
    @Test
    public void testOneItemCollection() {
    
        collection.add("itemA");
        assertEquals(1, collection.size());
    }
}

• Runner and @Runwith
  ​ JUnit Use cases are all in Runner（ Actuator ） To perform the . and RunWith You can specify a specific Runner. So most of the time we don't use @RunWith This annotation , This is because we use a default Runner, It is called BlockJunit4ClassRunner,** But it's in JUnit4.4 It was introduced later ,4.4 The previous version
  other
  @RunWith(Suite.class) And @Suite.SuiteClasses

@RunWith(Parameterized.class) And @Parameters

@RunWith(Categories.class) And @Category

@RunWith(Theories.class) And @Theory

@Rule,@ClassRule Of JUnit, It is called Junit4ClassRunner**.

• A practical Junit Single test example

public class SchoolServiceImplTest {
    
    private SchoolService schoolService;
        
    /** * This method initialize all domain objects required for test methods. */
    @Before
    public final void setUp() throws Exception {
    
 
        // Instantiates a School instance;
        school = new School();
        school.setName("sms School");
        school.setAddress("sms School");
        school.setContactNo("0123456789");
        school.setFaxNo("0123456789");
        school.setWebsite("javaguides.net");
        school.setStartedDate(date);
        school.setModifiedTime(date);       
    }
   
    @Test
    public final void testAddSchool() throws Exception {
    
            School newSchool = schoolService.addSchool(school);
            assertNotNull("School Type object should not null ", newSchool); 
    }
 
    
    @Test
    public final void testUpdateSchool() {
    
            School newSchool = schoolService.addSchool(school);
            assertNotNull(newSchool);
            newSchool.setContactNo("0145785545");
            schoolService.updateSchool(newSchool);
    }
 
    @Test
    public final void testFindSchool() throws AkuraAppException {
    
 
            School newSchool = schoolService.addSchool(school);
            assertNotNull(newSchool);
            School findSchool = schoolService.findSchool(
                    newSchool.getSchoolId());
            assertNotNull("School Type object should not null ", findSchool);
    }
 
    
    @Test
    public final void testGetSchoolList() throws AkuraAppException {
    
            School newSchool = schoolService.addSchool(school);
            assertNotNull(newSchool);
            List<School> schoolList = schoolService.getSchoolList();
    }
 
    
    @After
    public final void teardown() throws SchoolNotFoundException {
      
         schoolDao.delete(school);
    }
}