JUnit

• JUnit provide automated testing and validation.
• JUnit provides tools to unit test all aspects of program.

Using it with IDE

it is integrated with IDEs such as (eclipse, netbeans, intelij idea).

Use it with command line

• add environment varibale to point to JUNIT_HOME as where jar file is located.
• set path using set classpath=%JUNIT_HOME%\junit-2.14.jar
• move code file to JUNIT_HOME
• compile file using javac -cp .;junit-2.14.jar calc.java
• run with java -cp .;junit-2.14.jar;hancert.jar org.junit.runner.JUnitCore calcTest

IDEA

• we identify expected values and put actual values and JUnit do rest of work.
• easy to run many tests at same time.

Example

import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class TestSum {
    // annotte method with @Test
    @Test 
    public void testSum(){
        int n1 = 10 , n2 = 20 ;
        // use Assert to set Conditions to test, first value is expected, second is actual
        assertEquals(30 , n1+n2);
        // there are several methods, assertEquals, assertSame, assertNull.  
    }
}

Aggregate Tests into Suite

• we can aggregate test classes and all together
• exmaple

  import org.junit.runner.RunWith;
  import org.junit.runners.Suite;
  
  @RunWith(Suite.class) // speciffy runners. 
  @Suite.SuiteClasses({ // add test classes.
          TestMul.class,
          TestMul.class
  })
  public class TestSuit {
  
  }
  

Exception Handling tests

• we must test that program run corrrectly when things goes wrong.
• example

  import org.junit.Test;
  
  import java.util.ArrayList;
  
  public class TestException {
  
  // make sure that this method raise an exception from type of ArrayIndexOutOfBoundsException
  @Test(expected = IndexOutOfBoundsException.class)
  public void test(){
      new ArrayList<Object>().get(0);
  }
  }
  
  

Ignor tests

we may need to ignor some tests possible ways

• delete/comment method.
• remove @Test annotation.
• best one is use @Ignore annotation it skips test and JUnit report it at end of excution tests.

Paramaterized tests

• JUnit 4 they added another feature that allows you run paramaterized tests.

• This feature allows the developer to run tests, including multiple values at one time.

• Example

  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.Parameterized;
  import org.junit.runners.Parameterized.Parameters;
  
  import java.util.Arrays;
  import java.util.Collection;
  
  import static org.hamcrest.CoreMatchers.is;
  import static org.junit.Assert.assertThat;
  
  @RunWith(value = Parameterized.class)
  public class ParamaterizedTest {
  
      private int A ;
      private int B ;
      private int Expected ;
  
      public ParamaterizedTest(int a, int b, int expected) {
          A = a;
          B = b;
          Expected = expected;
      }
      // name attribute is optional, provide an unique name for test
      // multiple parameters, uses Collection<Object[]>
      @Parameters
      public static Collection<Object[]> data() {
          return Arrays.asList(new Object[][]{
                  // each one represent a data for single test A,B, Expected.
                  {1,2,3} ,
                  {2,3,5} ,
                  {3,4,7}
          });
      }
      @Test
      public void test(){
          assertThat(A+B , is(Expected));
      }
  }