This document provides an overview of JUnit, a unit testing framework for Java. It discusses what JUnit is, the benefits of using JUnit over traditional print-based testing, and the key components and functionality that JUnit provides such as assertions, test fixtures, test runners and reporting. The document also provides examples of how to write basic JUnit tests with assertions and explains concepts like test methods, test suites and how to include JUnit in a Java project.

1. Company
LOGO
JUnit
Week 8, Session 3
Lecturer : ACB
- STQA IE 31315 -
Institut Teknologi Del
Jl. Sisingamangaraja
Sitoluama, Laguboti 22381
Toba – SUMUT
http://www.del.ac.id

2. Topics
 What is JUnit?
 Why JUnit framework?
 JUnit mechanics
 Fixtures
 Test suites
 Test runners
 JUnit classes
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3. What is JUnit?
 An unit-testing tool for Java programs
 Supports Test-Driven-Development
 Agile Method
 Goal: Accelerate programming and
increase the quality of code.
 Not for testing GUI
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4. JUnit (cont’d)
 Each method under test is treated
as a unit
 The automated testing scripts are
in the form of methods in another
Java source file
 The job of the software
developers/testers is then to
write the automated testing
scripts
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5. Why Junit?
 Without JUnit, you will have to use
println() to print out some result:
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6. Why JUnit (cont’d)
Without JUnit:
 No explicit concept of test passing or
failure
 No mechanism to collect results in
structured fashion
 No replicability
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7. Key Goals of JUnit
 Easy to use to create tests
 Create tests that retain their value over
time
 Leverage existing tests to write new
ones (reusable)
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8. What does JUnit Provide?
 API for easily creating Java test cases
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9. What does JUnit Provide?
 Comprehensive assertion facilities
 verify expected versus actual results
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10. What does JUnit Provide?
 Test runners for running tests
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11. What does JUnit Provide?
 Reporting
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12. What does JUnit Provide?
Aggregation facility (test suites)
 Used to collect all the test cases
 Suites can contain testCases and
testSuites
– TestSuite(java.lang.Class theClass,
<java.lang.String name>)
– addTest(Test test) or
addTestSuite(java.lang.Class testClass)
 Suites can have hierarchy
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13. How to write JUnit-based
testing code (Minimum)
 Include JUnit.jar in the classpath
 Define a subclass of TestCase class
 Define one or more public testXXX()
methods in the subclass
 Write assert methods inside the testXXX
methods()
 Optionally define main() to run the
TestCase in standalone mode
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14. Test methods
 Test methods has name pattern: testXXX()
 XXX reflects the method of the target class
 Test methods must have no arguments
 Test methods are type of void
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15. Very Simple Test
import junit.framework.TestCase;
public class SimpleTest extends TestCase {
public SimpleTest(String name) {
super(name);
}
// Test code
public void testSomething() {
System.out.println("About to call assertTrue() method...");
assertTrue(4 == (2 * 2));
}
// You don't have to have main() method, use Test runner
public static void main(String[] args){
junit.textui.TestRunner.run(SimpleTest.class);
}
}
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16. Assert Statements
 JUnit Assertions are methods starting with
assert
 Determines the success or failure of a test
 An assert is simply a comparison between
 an expected value and an actual value
 Two variants
 assertXXX(...)
 assertXXX(String message, ...)
the message is displayed when the
assertXXX() fails
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17. Assert Statements
(cont’d)
 Asserts that a condition is true
– assertTrue(boolean condition)
– assertTrue(String message, boolean
condition)
 Asserts that a condition is false
– assertFalse(boolean condition)
– assertFalse(String message, boolean
condition)
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18. Assert Statements
(cont’d)
 Asserts expected.equals(actual) behavior
– assertEquals(expected, actual)
– assertEquals(String message, expected,
actual)
 Asserts expected == actual behavior
– assertSame(Object expected, Object
actual)
– assertSame(String message, Object
expected, Object actual)
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19. Assert Statements
(cont’d)
 Asserts object reference is null
– assertNull(Object obj)
– assertNull(String message, Object obj)
 Asserts object reference is not null
– assertNotNull(Object obj)
– assertNotNull(String message, Object obj)
 Forces a failure
– fail()
– fail(String message)
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20. Fixtures
 setUp() and tearDown() used to initialize
and release common test data
 setUp() is run before every test invocation
 tearDown() is run after every test method
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21. JUnit Classes
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22. References
 www.junit.org
 http://www.javapassion.com/javase/javaju
nit.pdf
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23. THANK YOU
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