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JUNIT - API

The most important package in JUnit is junit.framework, which contains all the core classes. Some of the important classes are as follows:

S. No.	Class Name	Functionality
1	Assert	A set of assert methods.
2	TestCase	A test case defines the fixture to run multiple tests.
3	TestResult	A TestResult collects the results of executing a test case.
4	TestSuite	A TestSuite is a composite of tests.

Assert Class

Following is the declaration for org.junit.Assert class:

public class Assert extends java.lang.Object

This class provides a set of assertion methods useful for writing tests. Only failed assertions are recorded. Some of the important methods of Assert class are as follows:

S.No.	Methods & Description
1	void assertEquals(boolean expected, boolean actual) Checks that two primitives/objects are equal.
2	void assertFalse(boolean condition) Checks that a condition is false.
3	void assertNotNull(Object object) Checks that an object isn't null.
4	void assertNull(Object object) Checks that an object is null.
5	void assertTrue(boolean condition) Checks that a condition is true.
6	void fail() Fails a test with no message.

Let's use some of the above-mentioned methods in an example. Create a java class file named TestJunit1.java in C:\>JUNIT_WORKSPACE.

import org.junit.Test;
import static org.junit.Assert.*;
public class TestJunit1 {
@Test
public void testAdd() {
//test data
int num= 5;
String temp= null;
String str= "Junit is working fine";
//check for equality
assertEquals("Junit is working fine", str);
//check for false condition
assertFalse(num > 6);
//check for not null value
assertNotNull(str);
}
}

Next, create a java class file named TestRunner1.java in C:\> JUNIT_WORKSPACE to execute test case(s).

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class TestRunner1 {
public static void main(String[] args) {
Result result = JUnitCore.runClasses(TestJunit1.class);
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
System.out.println(result.wasSuccessful());
}
}

Compile the test case and Test Runner classes using javac.

C:\JUNIT_WORKSPACE>javac TestJunit1.java TestRunner1.java

Now run the Test Runner, which will run the test case defined in the provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner1

Verify the output.

true

TestCase Class

Following is the declaration for org.junit.TestCaset class:

public abstract class TestCase extends Assert implements Test

A test case defines the fixture to run multiple tests. Some of the important methods of TestCase class are as follows:

S.No.	Methods & Description
1	int countTestCases() Counts the number of test cases executed by run(TestResult result).
2	TestResult createResult() Creates a default TestResult object.
3	String getName() Gets the name of a TestCase.
4	TestResult run() A convenience method to run this test, collecting the results with a default TestResult object.
5	void run(TestResult result) Runs the test case and collects the results in TestResult.
6	void setName(String name) Sets the name of a TestCase.
7	void setUp() Sets up the fixture, for example, open a network connection.
8	void tearDown() Tears down the fixture, for example, close a network connection.
9	String toString() Returns a string representation of the test case.

Let's use some of the above-mentioned methods in an example. Create a java class file named TestJunit2.java in C:\>JUNIT_WORKSPACE.

import junit.framework.TestCase;
import org.junit.Before;
import org.junit.Test;
public class TestJunit2 extends TestCase {
protected double fValue1;
protected double fValue2;
@Before
public void setUp() {
fValue1= 2.0;
fValue2= 3.0;
}
@Test
public void testAdd() {
//count the number of test cases
System.out.println("No of Test Case = "+ this.countTestCases());
//test getName
String name= this.getName();
System.out.println("Test Case Name = "+ name);
//test setName
this.setName("testNewAdd");
String newName= this.getName();
System.out.println("Updated Test Case Name = "+ newName);
}
//tearDown used to close the connection or clean up activities
public void tearDown( ) {
}
}

Next, create a java class file named TestRunner2.java in C:\> JUNIT_WORKSPACE to execute test case(s).

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class TestRunner2 {
public static void main(String[] args) {
Result result = JUnitCore.runClasses(TestJunit2.class);
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
System.out.println(result.wasSuccessful());
}
}

Compile the test case and Test Runner classes using javac.

C:\JUNIT_WORKSPACE>javac TestJunit2.java TestRunner2.java

Now run the Test Runner, which will run the test case defined in the provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner2

Verify the output.

No of Test Case = 1
Test Case Name = testAdd
Updated Test Case Name = testNewAdd
true

TestResult Class

Following is the declaration for org.junit.TestResult class:

public class TestResult extends Object

A TestResult collects the results of executing a test case. It is an instance of the Collecting Parameter pattern. The test framework distinguishes between failures and errors. A failure is anticipated and checked for with assertions. Errors are unanticipated problems like an ArrayIndexOutOfBoundsException. Some of the important methods of TestResult class are as follows:

S.No.	Methods & Description
1	void addError(Test test, Throwable t) Adds an error to the list of errors.
2	void addFailure(Test test, AssertionFailedError t) Adds a failure to the list of failures.
3	void endTest(Test test) Informs the result that a test was completed.
4	int errorCount() Gets the number of detected errors.
5	Enumeration<TestFailure> errors() Returns an Enumeration for the errors.
6	int failureCount() Gets the number of detected failures.
7	void run(TestCase test) Runs a TestCase.
8	int int runCount() Gets the number of run tests.
9	void startTest(Test test) Informs the result that a test will be started.
10	void stop() Marks that the test run should stop.

Create a java class file named TestJunit3.java in C:\> JUNIT_WORKSPACE.

import org.junit.Test;
import junit.framework.AssertionFailedError;
import junit.framework.TestResult;
public class TestJunit3 extends TestResult {
// add the error
public synchronized void addError(Test test, Throwable t) {
super.addError((junit.framework.Test) test, t);
}
// add the failure
public synchronized void addFailure(Test test, AssertionFailedError t) {
super.addFailure((junit.framework.Test) test, t);
}
@Test public void testAdd() {
// add any test
}
// Marks that the test run should stop.
public synchronized void stop() {
//stop the test here
}
}

Next, create a java class file named TestRunner3.java in C:\> JUNIT_WORKSPACE to execute test case(s).

import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class TestRunner3 {
public static void main(String[] args) {
Result result = JUnitCore.runClasses(TestJunit3.class);
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
System.out.println(result.wasSuccessful());
}
}

Compile the test case and Test Runner classes using javac.

C:\JUNIT_WORKSPACE>javac TestJunit3.java TestRunner3.java

Now run the Test Runner, which will run the test case defined in the provided Test Case class.

C:\JUNIT_WORKSPACE>java TestRunner3

Verify the output.

true

TestSuite Class

Following is the declaration for org.junit.TestSuite class:

public class TestSuite extends Object implements Test

A TestSuite is a composite of tests. It runs a collection of test cases. Some of the important methods of TestSuite class are as follows:

S.No.	Methods & Description
1	void addTest(Test test) Adds a test to the suite.
2	void addTestSuite(Class<? extends TestCase> testClass) Adds the tests from the given class to the suite.
3	int countTestCases() Counts the number of test cases that will be run by this test.
4	String getName() Returns the name of the suite.
5	void run(TestResult result) Runs the tests and collects their result in a TestResult.
6	void setName(String name) Sets the name of the suite.
7	Test testAt(int index) Returns the test at the given index.
8	int testCount() Returns the number of tests in this suite.
9	static Test warning(String message) Returns a test, which will fail and log a warning message.

Create a java class file named JunitTestSuite.java in C:\> JUNIT_WORKSPACE to create Test suite.

import junit.framework.*;
public class JunitTestSuite {
public static void main(String[] a) {
// add the test's in the suite
TestSuite suite = new TestSuite(TestJunit1.class, TestJunit2.class,
TestJunit3.class);
TestResult result = new TestResult();
suite.run(result);
System.out.println("Number of test cases = " + result.runCount());
}
}

Compile the Test suite classes using javac.

C:\JUNIT_WORKSPACE>javac JunitTestSuite.java

Now run the Test Suite.

C:\JUNIT_WORKSPACE>java JunitTestSuite

Verify the output.

No of Test Case = 1
Test Case Name = testAdd
Updated Test Case Name = testNewAdd
Number of test cases = 3

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JUNIT - API