JUnit4教程-优快云博客

Tutorial 1

This tutorial introduces the basic annotation supports that implemented in Junit 4.

import
 org.junit.*
;

import
 static
 org.junit
.Assert
.*;

import
 java.util.*
;

 
/**
 * @author mkyong
 *
 */

public
 class
 JunitTest1 {

 
    private
 Collection
 collection;

 
    @BeforeClass
    public
 static
 void
 oneTimeSetUp(
)
 {

        // one-time initialization code   

    	System
.out
.println
(
"@BeforeClass - oneTimeSetUp"
)
;

    }

 
    @AfterClass
    public
 static
 void
 oneTimeTearDown(
)
 {

        // one-time cleanup code

    	System
.out
.println
(
"@AfterClass - oneTimeTearDown"
)
;

    }

 
    @Before
    public
 void
 setUp(
)
 {

        collection =
 new
 ArrayList
(
)
;

        System
.out
.println
(
"@Before - setUp"
)
;

    }

 
    @After
    public
 void
 tearDown(
)
 {

        collection.clear
(
)
;

        System
.out
.println
(
"@After - tearDown"
)
;

    }

 
    @Test
    public
 void
 testEmptyCollection(
)
 {

        assertTrue(
collection.isEmpty
(
)
)
;

        System
.out
.println
(
"@Test - testEmptyCollection"
)
;

    }

 
    @Test
    public
 void
 testOneItemCollection(
)
 {

        collection.add
(
"itemA"
)
;

        assertEquals(
1
, collection.size
(
)
)
;

        System
.out
.println
(
"@Test - testOneItemCollection"
)
;

    }

}

Result

@BeforeClass – oneTimeSetUp
@Before – setUp
@Test – testEmptyCollection
@After – tearDown
@Before – setUp
@Test – testOneItemCollection
@After – tearDown
@AfterClass – oneTimeTearDown

In JUnit 4, we have to declare “@BeforeClass” and “@AfterClass” method as static method.

Tutorial 2

The “exception testing” means what exception throw from the unit test.

import
 org.junit.*
;

 
/**
 * JUnit Expected Exception Test
 * @author mkyong
 *
 */

public
 class
 JunitTest2 {

 
 
	@Test(
expected =
 ArithmeticException
.class
)
  
	public
 void
 divisionWithException(
)
 {
  
	  int
 i =
 1
/
0
;

	}
  
 
}

Result

Unit test marked success

Tutorial 3

The “Ignored” means whether it should ignore the unit test.

import
 org.junit.*
;

 
/**
 * JUnit Ignore Test
 * @author mkyong
 *
 */

public
 class
 JunitTest3 {

 
	@Ignore(
"Not Ready to Run"
)
  
	@Test
	public
 void
 divisionWithException(
)
 {
  
	  System
.out
.println
(
"Method is not ready yet"
)
;

	}
  
 
}

Result

unit test ignored

Tutorial 4

The “Time Test” means if an unit test takes longer than the specified number of milliseconds to run, the test will terminated and mark as fails.

import org.junit.*;
 
/**
 * JUnit TimeOut Test
 * @author mkyong
 *
 */
public class JunitTest4 {
 
	@Test(timeout = 1000)  
	public void infinity() {  
		while (true);  
	}  
 
}

Result

java.lang.Exception: test timed out after 1000 milliseconds

Tutorial 5

The “Suite Test” means bundle a few unit test and run it together.

The “@RunWith” and “@Suite” are use to run the suite test. The below class means both unit test “JunitTest1” and “JunitTest2” run together after JunitTest5 executed. All the declaration is define inside the class.

import
 org.junit.runner.RunWith
;

import
 org.junit.runners.Suite
;

 
/**
 * JUnit Suite Test
 * @author mkyong
 *
 */

 
@RunWith(
Suite.class
)

@Suite.SuiteClasses
(
{

        JunitTest1.class
,
        JunitTest2.class

}
)

public
 class
 JunitTest5 {

}

Result

@BeforeClass – oneTimeSetUp
@Before – setUp
@Test – testEmptyCollection
@After – tearDown
@Before – setUp
@Test – testOneItemCollection
@After – tearDown
@AfterClass – oneTimeTearDown

P.S Result is from JunitTest1 and JunitTest2 unit test

Tutorial6

The “Parameterized Test” means vary parameter value for unit test. The “@RunWith” and “@Parameter” is use to provide parameter value for unit test, @Parameters have to return List[], and the parameter will pass into class constructor as argument.

import
 java.util.Arrays
;

import
 java.util.Collection
;

 
import
 org.junit.Test
;

import
 org.junit.runner.RunWith
;

import
 org.junit.runners.Parameterized
;

import
 org.junit.runners.Parameterized.Parameters
;

 
/**
 * JUnit Parameterized Test
 * @author mkyong
 *
 */

@RunWith(
value =
 Parameterized.class
)

public
 class
 JunitTest6 {

 
	 private
 int
 number;

 
	 public
 JunitTest6(
int
 number)
 {

	    this
.number
 =
 number;

	 }

 
	 @Parameters
	 public
 static
 Collection<
Object[
]
>
 data(
)
 {

	   Object
[
]
[
]
 data =
 new
 Object
[
]
[
]
 {
 {
 1
 }
, {
 2
 }
, {
 3
 }
, {
 4
 }
 }
;

	   return
 Arrays
.asList
(
data)
;

	 }

 
	 @Test
	 public
 void
 pushTest(
)
 {

	   System
.out
.println
(
"Parameterized Number is : "
 +
 number)
;

	 }

 
 
}

Result

Parameterized Number is : 1
Parameterized Number is : 2
Parameterized Number is : 3
Parameterized Number is : 4

It has many limitations here; we have to follow the “JUnit” way to declare the parameter, and the parameter has to pass into constructor in order to initialize the class member as parameter value for testing. The return type of parameter class is “List []”, data has been limited to String or a primitive value for testing.