May 15, 2021 jUnit
All assertions are contained in the Assert class
public class Assert extends java.lang.ObjectThis class provides many useful assertion methods for writing test cases. O nly failed assertions are logged. eful method columns in the Assert class are as follows:
| Serial number | Method and description |
|---|---|
| 1 |
void assertEquals(boolean expected, boolean actual)
Check that the two variables or the equals are balanced |
| 2 |
void assertTrue(boolean expected, boolean actual)
The check condition is true |
| 3 |
void assertFalse(boolean condition)
The check condition is false |
| 4 |
void assertNotNull(Object object)
The check object is not empty |
| 5 |
void assertNull(Object object)
The check object is empty |
| 6 |
void assertSame(boolean condition)
The assertSame() method checks whether two related objects point to the same object |
| 7 |
void assertNotSame(boolean condition)
The assertNotSame() method checks whether two related objects do not point to the same object |
| 8 |
void assertArrayEquals(expectedArray, resultArray)
The assertArrayEquals() method checks that the two arrays are equal |
Let's experiment with the methods mentioned above in the example. I n C: A class JUNIT_WORKSPACE file name TestAssertions is created under the .java path
import org.junit.Test;
import static org.junit.Assert.*;
public class TestAssertions {
@Test
public void testAssertions() {
//test data
String str1 = new String ("abc");
String str2 = new String ("abc");
String str3 = null;
String str4 = "abc";
String str5 = "abc";
int val1 = 5;
int val2 = 6;
String[] expectedArray = {"one", "two", "three"};
String[] resultArray = {"one", "two", "three"};
//Check that two objects are equal
assertEquals(str1, str2);
//Check that a condition is true
assertTrue (val1 < val2);
//Check that a condition is false
assertFalse(val1 > val2);
//Check that an object isn't null
assertNotNull(str1);
//Check that an object is null
assertNull(str3);
//Check if two object references point to the same object
assertSame(str4,str5);
//Check if two object references not point to the same object
assertNotSame(str1,str3);
//Check whether two arrays are equal to each other.
assertArrayEquals(expectedArray, resultArray);
}
}Next, we'll be at C: T his is JUNIT_WORKSPACE a class named TestRunner under the .java to execute the test case
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(TestAssertions.class);
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
System.out.println(result.wasSuccessful());
}
} The Test case and Test Runner classes are compiled with javac
C:\JUNIT_WORKSPACE>javac TestAssertions.java TestRunner.java
Run Test Runner, which will now run the test cases defined and provided in the Test Case class
C:\JUNIT_WORKSPACE>java TestRunnerCheck the results of the run
true
Annotations are like meta-tags that you can add to your code and apply in a method or class.
These annotations in JUnit provide us with information about the test methods, which methods will be applied before and after the test methods, which methods will be applied before and after all methods, and which methods will be ignored in execution.
List of annotations in JUnit and what they mean:
| Serial number | Notes and descriptions |
|---|---|
| 1 |
@Test
This annotation illustrates that the public void method attached to JUnit can be used as a test case. |
| 2 |
@Before
Some tests need to create several similar objects before running. The annotation is added to the public void method because it needs to run before the test method. |
| 3 |
@After
If you allocate external resources in the Before method, you need to release them after the test runs. The annotation is added to the public void method because it needs to run after the test method. |
| 4 |
@BeforeClass
The annotation is added to the public void method because it needs to run before all methods in the class. |
| 5 |
@AfterClass
It will cause the method to execute after all tests have ended. This can be used for cleanup activities. |
| 6 |
@Ignore
This annotation is used to ignore tests that do not need to be performed. |
In C: This JUNIT_WORKSPACE a class named JunitAnnotation under the .java to test the annotations
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;
public class JunitAnnotation {
//execute before class
@BeforeClass
public static void beforeClass() {
System.out.println("in before class");
}
//execute after class
@AfterClass
public static void afterClass() {
System.out.println("in after class");
}
//execute before test
@Before
public void before() {
System.out.println("in before");
}
//execute after test
@After
public void after() {
System.out.println("in after");
}
//test case
@Test
public void test() {
System.out.println("in test");
}
//test case ignore and will not execute
@Ignore
public void ignoreTest() {
System.out.println("in ignore test");
}
}Next, we'll be at C: A class JUNIT_WORKSPACE file named TestRunner is created under the .java to perform annotations
import org.junit.runner.JUnitCore;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
public class TestRunner {
public static void main(String[] args) {
Result result = JUnitCore.runClasses(JunitAnnotation.class);
for (Failure failure : result.getFailures()) {
System.out.println(failure.toString());
}
System.out.println(result.wasSuccessful());
}
} The Test case and Test Runner classes are compiled with javac
C:\JUNIT_WORKSPACE>javac TestAssertions.java TestRunner.javaRun Test Runner, which will now run the test cases defined and provided in the Test Case class
C:\JUNIT_WORKSPACE>java TestRunnerCheck the results of the run
in before class
in before
in test
in after
in after class
true