Unit testing - презентацията на Наков на ВарнаКонф 2013 - http://www.varnaconf.com

1. UnitTesting
Building Rock-Solid Software
Svetlin Nakov
Telerik Software Academy
http://academy.telerik.com
ManagerTechnicalTraining
http://www.nakov.com

2. What is UnitTesting?

3. UnitTest – Definition
A unit test is a piece of code written by
a developer that exercises a very small,
specific area of functionality of the code
being tested.
“Program testing can be used to show the
presence of bugs, but never to show their
absence!”
Edsger Dijkstra, [1972]

4. UnitTest – Example
int sum(int[] array) {
int sum = 0;
for (int i=0; i<array.length; i++)
sum += array[i];
return sum;
}
void testSum() {
if (sum(new int[]{1,2}) != 3)
throw new TestFailedException("1+2 != 3");
if (sum(new int[]{-2}) != -2)
throw new TestFailedException("-2 != -2");
if (sum(new int[]{}) != 0)
throw new TestFailedException("0 != 0");
}

5. UnitTesting – Some Facts
 Tests are pieces of code (small programs)
 In most cases unit tests are written by
developers, not by QA engineers
 Unit tests are released into the code repository
(TFS / SVN / Git) along with the code they test
 Unit testing framework is needed
 Visual StudioTeamTest (VSTT)
 NUnit, MbUnit, Gallio, etc.
5

6. UnitTesting
Frameworks & JUnit

7. UnitTesting Frameworks
 JUnit
 The first popular unit testing framework
 Based on Java, written by Kent Beck & Co.
 Similar frameworks have been developed for a
broad range of computer languages
 NUnit – for C# and all .NET languages
 cppUnit, jsUnit, PhpUnit, PerlUnit, ...
 Visual StudioTeamTest (VSTT)
 Developed by Microsoft, integrated inVS
7

8. UnitTesting Frameworks
 JUnit – the first unit testing framework
 www.junit.org
 Based on Java
 Developed by Erich Gamma and Kent Beck
 Unit testing frameworks have been developed for a
broad range of computer languages
 NUnit – for C#,VB.NET and .NET languages
 cppUnit, DUnit, jsUnit, PhpUnit, PerlUnit, ...
 List of xUnit frameworks can be found at:
http://www.testingfaqs.org/t-unit.html

9. JUnit – Features
 Test code is annotated using Java 5
annotations
 Test code contains assertions
 Tests are grouped in test fixtures and test
suites
 Several execution interfaces
 Eclipse integrated plug-in
 Console interface:
java org.junit.runner.JUnitCore <test-class>

10. JUnit – Annotations
 @Test
 Annotates a test case method
 @Before, @After
 Annotates methods called before/after each test
case
 @BeforeClass, @AfterClass
 Annotates methods called one time before and
after all test cases in the class
 @Ignore
 Ignores a test case
10

11. JUnit – Assertions
 Using org.junit.Assert class
 Assertions check a condition and throw exception if
the condition is not satisfied
 Comparing values
 assertEquals ([message], expected value,
calculated value)
 Comparing objects
 assertNull([message], object)
 assertNotNull([message], object)
 assertSame ([message], expected obj,
calculated obj)

12. JUnit – Assertions (2)
 Conditions
 assertTrue(condition)
 assertFalse(condition)
 Forced test fail
 fail()
 Expecting exception
 @Test(expected=IndexOutOfBoundsExcept
ion.class)

13.  Java class that needs unit testing:
JUnit – Example
public class Sumator {
public int sum(int a, int b) {
int sum = a + b;
return sum;
}
public int sum(int... nums) {
int sum = 0;
for (int i = 0; i < nums; i++)
sum += nums[i];
return sum;
}
}

14.  JUnit based test class (fixture):
JUnit – Example
import org.junit.Test;
import static org.junit.Assert.*;
public class SumatorTest {
@Test
public void testSum() {
Sumator sumator = new Sumator();
int sum = sumator.sum(new int[] {2,3,4});
assertEquals(sum, 9);
}
}

15.  JUnit text fixture with setup and cleanup:
JUnit – Example
public class SumatorTest {
private Sumator sumator;
@Before public void setUpTestCase() {
this.sumator = new Sumator();
}
@Test public void testSum() {
int sum = sumator.sum(2, 3);
assertEquals(sum, 5);
}
@After public void cleanUpTestCase() {
this.sumator = null;
}
}

16. Test Suites
 Suits are sets of JUnit test classes
 We can define test suits with annotations:
import org.junit.runner.RunWith;
import org.junit.runners.Suite;
import org.junit.runners.Suite.SuiteClasses;
@RunWith(value=Suite.class)
@SuiteClasses(value={Test1.class, Test2.class})
public class AllTests {
}

17. Eclipse and JUnit
 Eclipse has
built-in
support for
integration
with JUnit
 Can create,
run and
debug JUnit
tests

18. Testing with JUnit
Live Demo

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