
TestNG provides an option of tracing the exception handling of code. You can test whether a code throws a desired exception or not. Here the expectedExceptions parameter is used along with the @Test annotation. Now, let's see @Test(expectedExceptions) in action.
Create a java class to be tested, say, MessageUtil.java in C:\> TestNG_WORKSPACE. Add an error condition inside the printMessage() method.
/*
* This class prints the given message on console.
*/
public class MessageUtil {
private String message;
//Constructor
//@param message to be printed
public MessageUtil(String message) {
this.message = message;
}
// prints the message
public void printMessage() {
System.out.println(message);
int a =0;
int b = 1/a;
}
// add "Hi!" to the message
public String salutationMessage() {
message = "Hi!" + message;
System.out.println(message);
return message;
}
}
Create a java test class, say, ExpectedExceptionTest.java.
Add an expected exception ArithmeticException to the testPrintMessage() test case.
Create a java class file named ExpectedExceptionTest.java in C:\> TestNG_WORKSPACE.
import org.testng.Assert;
import org.testng.annotations.Test;
public class ExpectedExceptionTest {
String message = "Manisha";
MessageUtil messageUtil = new MessageUtil(message);
@Test(expectedExceptions = ArithmeticException.class)
public void testPrintMessage() {
System.out.println("Inside testPrintMessage()");
messageUtil.printMessage();
}
@Test
public void testSalutationMessage() {
System.out.println("Inside testSalutationMessage()");
message = "Hi!" + "Manisha";
Assert.assertEquals(message,messageUtil.salutationMessage());
}
}
Create testng.xml in C:\>TestNG_WORKSPACE to execute test case(s).
<?xml version = "1.0" encoding = "UTF-8"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >
<suite name = "Suite1">
<test name = "test1">
<classes>
<class name = "ExpectedExceptionTest" />
</classes>
</test>
</suite>
Compile the MessageUtil, Test case classes using javac.
C:\TestNG_WORKSPACE>javac MessageUtil.java TestJunit.java
Now, run the Test Runner, which will run test cases defined in the provided Test Case class.
C:\TestNG_WORKSPACE>java -cp "C:\TestNG_WORKSPACE" org.testng.TestNG testng.xml
Verify the output. testPrintMessage() test case will be passed.
Inside testPrintMessage() Manisha Inside testSalutationMessage() Hi!Manisha =============================================== Suite1 Total tests run: 2, Failures: 0, Skips: 0 ===============================================