JUnit Parametrized Tests

Junit allows us to create parametrized tests. Parametrized test class has to be annotated with the @RunWith(Parameterized.class). The parametrized test class also meets below requirements:

It is annotated with @RunWith(Parameterized.class).
It has a single constructor that contains the test data.
It has a static method which annotated with @parameters annotation and generates and returns test data. Each test data is used as parameter for the test method.
It needs a test method that annotated with @test annotation.

Class Under Test: Addition.java

public class Addition {
    public int AddOperation (int a, int b) {
        int result = a+b;
        System.out.println("Addition with: " + a + " + " + b  + " = " + result);
        return result;
    }
}

package junitexamples.ParametrizedTests;
 
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
 
import java.util.Arrays;
import java.util.Collection;
 
import static org.junit.Assert.assertEquals;
 
/**
 * Created by ONUR on 20.09.2015.
 */
@RunWith(Parameterized.class)
public class ParametrizedTestWithConstructor {
    //Private variables
    private int v1;
    private int v2;
    private int summation;
 
    //Constructor
    public ParametrizedTestWithConstructor(int p1, int p2, int p3) {
        this.v1 = p1;
        this.v2 = p2;
        this.summation = p3;
    }
 
    //Creating test data
    @Parameterized.Parameters
    public static Collection<Object[fusion_builder_container hundred_percent="yes" overflow="visible"][fusion_builder_row][fusion_builder_column type="1_1" background_position="left top" background_color="" border_size="" border_color="" border_style="solid" spacing="yes" background_image="" background_repeat="no-repeat" padding="" margin_top="0px" margin_bottom="0px" class="" id="" animation_type="" animation_speed="0.3" animation_direction="left" hide_on_mobile="no" center_content="no" min_height="none"][]> data() {
        Object[][] dataValues = new Object[][] { { 4 , 3, 7 }, { 7, 8, 15 }, { 2, 9, 11} };
        return Arrays.asList(dataValues);
    }
 
 
    //Test addoperation method of class Addition
    @Test
    public void testAddition() {
            Addition add = new Addition();
            assertEquals("Addition Failed!", summation, add.AddOperation(v1, v2));
            System.out.println("Test for " + v1 + " and " + v2 + " has been passed!\n");
    }
}

It is also possible to inject data values directly into fields without needing a constructor using the @Parameter annotation.

package junitexamples.ParametrizedTests;
 
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
 
import java.util.Arrays;
import java.util.Collection;
 
import static org.junit.Assert.assertEquals;
 
/**
 * Created by ONUR on 20.09.2015.
 */
@RunWith(Parameterized.class)
public class ParametrizedTestWithParameterAnnotation {
    //Private variables
    //Variables using together with @Parameter must be public
    @Parameterized.Parameter (value=0)
    public int v1;
    @Parameterized.Parameter (value=1)
    public int v2;
    @Parameterized.Parameter (value=2)
    public int summation;
 
    //Creating test data
    @Parameterized.Parameters
    public static Collection<Object[]> data() {
        Object[][] data = new Object[][] { { 4 , 3, 7 }, { 7, 8, 15 }, { 2, 9, 11 } };
        return Arrays.asList(data);
    }
 
    //Test addoperation method of class Addition
    @Test
    public void testAddition() {
        Addition add = new Addition();
        assertEquals("Addition Failed!", summation, add.AddOperation(v1, v2));
        System.out.println("Test for " + v1 + " and " + v2 + " has been passed!\n");
    }
}

Output:

Addition with: 4 + 3 = 7
Test for 4 and 3 has been passed!
 
Addition with: 7 + 8 = 15
Test for 7 and 8 has been passed!
 
Addition with: 2 + 9 = 11
Test for 2 and 9 has been passed!

Summary

You learned how to write parametrized tests with constructor and without constructor.
You practiced with parametrized test examples.

Keywords

JUnit, parametrized tests, unit testing, test framework

JUnit Parametrized Tests

Summary

Keywords

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