{"id":7582,"date":"2013-12-19T12:14:19","date_gmt":"2013-12-19T10:14:19","guid":{"rendered":"http:\/\/examples.javacodegeeks.com\/?p=7582"},"modified":"2019-03-21T12:52:19","modified_gmt":"2019-03-21T10:52:19","slug":"junit-exceptions-test-example","status":"publish","type":"post","link":"https:\/\/examples.javacodegeeks.com\/java-development\/core-java\/junit\/junit-exceptions-test-example\/","title":{"rendered":"JUnit Exceptions Test Example"},"content":{"rendered":"

In this example we are going to see how to use @Test<\/code> annotation along with its optional parameter expected<\/strong><\/code> in JUnit<\/a> testing framework. Also, we will see how to run our test case from the command line by using the org.junit.runner.JUnitCore<\/a><\/code>.<\/p>\n

1. Create the java class to be tested
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Create a folder named JUnitExceptions<\/code>. This is the folder where your classes will be located. Using a text editor, create a Java class named FirstDayAtSchool.java<\/code>. To make sure your file name is FirstDayAtSchool.java<\/code>, (not FirstDayAtSchool.java.txt<\/code>), first choose “Save as -> Save as type -> All files”<\/em>, then type in the file name FirstDayAtSchool.java<\/code>.<\/p>\n

 
\nFirstDayAtSchool.java<\/em><\/span><\/p>\n

import java.util.Arrays;\n\npublic class FirstDayAtSchool {\n\n\tpublic String[] prepareMyBag() {\n\t\tString[] schoolbag = { \"Books\", \"Notebooks\", \"Pens\" };\n\t\tSystem.out.println(\"I put in my bag: \"+Arrays.toString(schoolbag));\n\t\treturn (schoolbag);\n\t}\n\n\tpublic void printItems(String []items) {\n\t\t\n\t\tSystem.out.println(\"The last item I put in my bag was: \" +items[items.length]);\n\t\t\n\t}\n}\n<\/pre>\n
2. Create JUnit test case
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In the same directory (JUnitExceptions<\/code>), use a text editor and create a java class named JunitExceptionsTest1.java<\/code> with the following code.<\/p>\n
JunitExceptionsTest1.java<\/em><\/span><\/p>\n
import static org.junit.Assert.assertArrayEquals;\nimport org.junit.Test;\n\npublic class JunitExceptionsTest1 {\n\n\tFirstDayAtSchool school = new FirstDayAtSchool();\n\tString[] bag = { \"Books\", \"Notebooks\", \"Pens\" };\n\n\t@Test\n\tpublic void testPrepareMyBag() {\n\t\tSystem.out.println(\"Inside testPrepareMyBag()\");\n\t\tassertArrayEquals(bag, school.prepareMyBag());\n\t}\n\n\t@Test(expected = ArrayIndexOutOfBoundsException.class)\n\tpublic void testPrintItems() {\n\t\tSystem.out.println(\"Inside printItems()\");\n\t\tschool.printItems(bag);\n\t}\n}\n<\/pre>\n
In the same way, create another class named JunitExceptionsTest2.java<\/code> with similar code, where the only difference with the previous class will be the declared exception.<\/p>\n
JunitExceptionsTest2.java<\/em><\/span><\/p>\n
import static org.junit.Assert.assertArrayEquals;\nimport org.junit.Test;\n\npublic class JunitExceptionsTest2 {\n\n\tFirstDayAtSchool school = new FirstDayAtSchool();\n\tString[] bag = { \"Books\", \"Notebooks\", \"Pens\" };\n\n\t@Test\n\tpublic void testPrepareMyBag() {\n\t\tSystem.out.println(\"Inside testPrepareMyBag()\");\n\t\tassertArrayEquals(bag, school.prepareMyBag());\n\t}\n\n\t@Test(expected = ArithmeticException.class)\n\tpublic void testPrintItems() {\n\t\tSystem.out.println(\"Inside printItems()\");\n\t\tschool.printItems(bag);\n\t}\n}\n<\/pre>\n
In the method testPrintItems()<\/code> in both java classes, we can see that @Test <\/code> annotation is followed by a parameter, called expected<\/code>. The expected<\/code> is an optional parameter supported by @Test <\/code>annotation which declares that a test method should throw an exception. If it doesn’t throw an exception or if it throws a different exception than the one declared, the test fails, otherwise it succeeds.
 
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For further details regarding the @Test<\/code> annotation, the assertArrayEquals<\/code> assertion (which are also mentioned in our code) and other JUnit Assertions and Annotations, you can have a look at JUnit using Assertions and Annotations Example<\/a>.<\/p>\n
3. Run your test cases from the command line
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You can run your JUnit test outside Eclipse, by using the org.junit.runner.JUnitCore<\/code> class. This class provides the runClasses()<\/code> method which allows you to execute one or several test classes. The return type of runClasses()<\/code> method is an object of the type org.junit.runner.Result<\/a><\/code>. This object can be used to collect information about the tests. Also, in case there is a failed test, you can use the object org.junit.runner.notification.Failure<\/a><\/code> which holds description of the failed tests.<\/p>\n
The procedure below shows how to run your test outside Eclipse.<\/p>\n
In the directory JUnitExceptions<\/code>, use a text editor and create a new Java class named JunitExceptionsTestRunner.java<\/code> with the following code.<\/p>\n
JunitExceptionsTestRunner.java<\/em><\/span><\/p>\n
import org.junit.runner.JUnitCore;\nimport org.junit.runner.Result;\nimport org.junit.runner.notification.Failure;\n\npublic class JunitExceptionsTestRunner {\n\n\tpublic static void main(String[] args) {\n\n\t\tResult result = JUnitCore.runClasses(JunitExceptionsTest1.class);\n\t\tfor (Failure fail : result.getFailures()) {\n\t\t\tSystem.out.println(fail.toString());\n\t\t}\n\t\tif (result.wasSuccessful()) {\n\t\t\tSystem.out.println(\"All tests finished successfully...\");\n\t\t}\n\t}\n}\n<\/pre>\n
We will first run the JunitExceptions1.java,<\/code> so the argument of runClasses<\/code> method will be the perspective class.<\/p>\n