
In my last post about [Getting Started with JUnit 4][1], I talked about the basic concepts of JUnit testing framework and how to write a test case using JUnit 4. In this post, I'll write about some tips and strategies for using JUnit effectively. We will start with JUnit annotation @Ignore.

[1]: https://veerasundar.com/blog/getting-started-with-junit-4-java-testing-framework "Getting started with JUnit 4 - In order to test the java applications effectivley, we can use JUnit. framework Junit is an open source, Java testing framework that helps us to write and run tests for our application. Using JUnit, we can setup your testing objects, write the test methods for our objects, run those test methods and assert the testing outcomes for expected results."

## Temporarily disabling a JUnit test:

In JUnit 4, it is possible to temperorily disable a test using the annotation **_@Ignore_**. This technique is very useful in scenarios where you are not done with that particular test case, but still want to run the other tests that are present in that test suite/class. The test methods which are annotated with both _@Test_ and _@Ignore_ will be ignored by the test runner. See the example below for a clear understanding.

```java
    @Test
    public void testSomeMethod(){
            System.out.println("T'll be called");
    }

    @Ignore
    @Test
    public void testSomeOtherMethod(){
            System.out.println("T'll be ignored");
    }
```

## Testing for a specific Exception in JUnit testing method:

Suppose you want to check for a specific exception thrown by your testing method, you can use the **_expected_** option of _@Test_ annotation. You can mention the Exception type that you expect the testing method to throw in the 'Ëœexpected' option. If the method throws the exception then test is considered as passed, otherwise the test will be considered as failed.

```java
    @Test(expected=IllegalArgumentException.class)
    public void testSomeMethod(){
       myObj.someMethod();
    }
```

## Testing for execution time of your method:

If you want to check if your testing method takes too long to execute, you can do that by mentioning your expected execution time using **_timeout_** option of @Test annotation. If your testing method takes longer than the time you mentioned, then the test will be considred as _failed._ The time is measured in _milliseconds._ Below is a code snippet for this.

```java
    @Test(timeout=2000)
    public void testSomeMethod(){
       myObj.someMethod();
    }
```

That's for now. I hope that the above tips will help you t write effective JUnit tests. Feel free to share any other tips on JUnit. I'll happy to hear from you.


JUnit 4 - testing for exception, execution time and disabling a test


One of the important skill that every Java developer must possess is the **application testing**. A developer may follow software standards, religiously use all the available design patterns or do hundreds of code reviews on his code, but testing is the one which confirms his code quality and reliability. This is proved by the growing popularity of **Test Driven Development (TDD)** methodology, where the developer write tests first and the build the application to pass those tests. The objective of this post is not to explain TDD or the bigger things. Instead I'll focus on the basic things first. This is a very basic introduction to JUnit, so if you already knew about JUnit, you can safely skip reading this blog post.

All of us, the java developers, would have used a well-proven testing method, when we started learning Java. It's called as the **'ËœSyso testing'**, which is nothing but _System.out.println()_ . We usually print the variable values in the console and check them manually to make sure that the function is doing what it has to do. For small projects, this approach is quick and useful. But, for the medium/big sized projects, using 'ËœSyso testing' isn't that effective. Even for small projects, using Syso testing will turn ineffective as the development continues.

In order to test the java applications effectivley, we can use **JUnit. framework** Junit is an open source, Java testing framework that helps us to write and run tests for our application. Using JUnit, we can setup your testing objects, write the test methods for our objects, run those test methods and assert the testing outcomes for expected results. Since running the test methods can be automated (either by using Ant/IDEs built-in JUnit support), considerable amount of time can be saved during the testing phase.

## Basic steps needed for writing a JUnit test case:

1.  First, we need to write the Java class (duh!). Let's say we have the below _PayrollCalculator_ java class, which I'm going to use as an example.  

```java
        package com.veerasundar.budgeter;
        public class PayrollCalculator {

        	public double calculate(double rate, int days) {
        		return rate * days;
        	}

        }
```

2.  Then, we need to create a new Test class with testing methods in it. We can create this test class in the same package as of _PayrollCalculator._ But for better organization, it is recommended to have the test classes in a different folders. So, create a new _source folder_ and put the below test class in it.  

```java
        package com.veerasundar.budgeter.junit;

        import static org.junit.Assert.assertEquals;

        import org.junit.Test;

        import com.veerasundar.budgeter.PayrollCalculator;

        public class PayrollTesCase {

        	@Test
        	public void testCalculate() {
        		PayrollCalculator payCalc = new PayrollCalculator();
        		assertEquals(300 * 30, payCalc.calculate(300, 30));

        		System.out.println("I'm the test method");
        	}

        }
```

3.  In Junit 4.x, all the testing methods are identified with **@Test** annotation.so, the method _testCalculate_ will be identified as test method and will be run by the Junit runner.
4.  If you are using an IDE such as Eclipse, the _PayrollTestCase_ class can be executed by right-clicking on the test class and selecting **Run as JUnit test case.** This will invoke the test environment methods, if any (explained later in this article) and then invoke all the methods that are annotated with @Test annotation. If the assert statement that we put inside those test methods are success, then JUnit will run successfully. Otherwise, the errors will be reported in the **JUnit view** in Eclipse window.

## Understanding how an JUnit test method is executed

When you run a JUnit test case, you can optionally specify some other methods also to be executed along with your test method. Bascially this _additional_ methods are used to setup your testing environment, for example getting a database connection, and for releasing the resources used during the testing such as closing the database connection. These methods are called as _fixtures_ and can be used to initialize the objects that are used by more than one test methods, thus reducing the amount of code.

In JUnit 4.x all the methods are annotated. So, the flow of control in JUnit methods can be described as below:

> @BeforeClass -> @Before -> @Test -> @After -> @AfterClass

You can annotate any method with the above-mentioned annotation. See the below coding example to know how these annotated methods are executed.

```java
    package com.veerasundar.budgeter.junit;

    import static org.junit.Assert.assertEquals;

    import org.junit.After;
    import org.junit.AfterClass;
    import org.junit.Before;
    import org.junit.BeforeClass;
    import org.junit.Test;

    import com.veerasundar.budgeter.PayrollCalculator;

    public class PayrollTesCase {

    	@BeforeClass
    	public static void runsBeforeTheTestSuite(){
    		System.out.println("I run before any test method is executed");
    	}


    	@Before
    	public void runOnceBeforeEachTestMethod(){
    		System.out.println("I run once before each test method is executed");
    	}


    	@Test
    	public void testCalculate() {
    		PayrollCalculator payCalc = new PayrollCalculator();
    		assertEquals(300 * 30, payCalc.calculate(300, 30));

    		System.out.println("I'm the test method");
    	}

    	@After
    	public void runOnceAfterEachTestMethod(){
    		System.out.println("I run once after each test method is executed");
    	}

    	@AfterClass
    	public static void runsAfterTheTestSuite(){
    		System.out.println("I run after all the test methods are executed");
    	}
    }
```

Also, please note that the methods annotated with @BeforeClass and @AfterClass should be _static methods_ since they will be called before any test method is executed.

I hope this post explains the basics of JUnit 4 clearly. In my next post, I'll be sharing some more tips on JUnit testing.


#junit4 (2)