@ValueSource for simple values in JUnit - Build an Automation Script

Test isEven method with multiple integer inputs using @ValueSource

Preconditions (2)

Step 1: Create a parameterized test method using @ValueSource with integers: 2, 4, 6, 8, 10

Step 2: For each integer input, call isEven(number)

Step 3: Verify that the method returns true for all inputs

✅ Expected Result: The test passes confirming isEven returns true for all even numbers provided

Automation Requirements - JUnit 5

Assertions Needed:

Assert that isEven returns true for each input value

Best Practices:

Use @ParameterizedTest with @ValueSource for simple input values

Use descriptive test method names

Keep test methods focused on one behavior

Use assertions from org.junit.jupiter.api.Assertions

Automated Solution

JUnit

import static org.junit.jupiter.api.Assertions.assertTrue;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;

public class NumberUtilsTest {

    // Method to test
    public static boolean isEven(int number) {
        return number % 2 == 0;
    }

    @ParameterizedTest
    @ValueSource(ints = {2, 4, 6, 8, 10})
    void testIsEvenWithEvenNumbers(int number) {
        assertTrue(isEven(number), "Number " + number + " should be even");
    }
}

The test class NumberUtilsTest contains the method isEven which returns true if the number is even.

The test method testIsEvenWithEvenNumbers is annotated with @ParameterizedTest and @ValueSource to run the test multiple times with different integer inputs.

For each input, the test asserts that isEven returns true, confirming the method works correctly for even numbers.

This approach avoids writing multiple test methods for each input and keeps tests clean and readable.

Common Mistakes - 3 Pitfalls

Using @Test instead of @ParameterizedTest for multiple inputs

Passing values as strings instead of correct type in @ValueSource

Not asserting the expected result inside the test method

Bonus Challenge

Now add data-driven testing with 3 different inputs including even and odd numbers and verify isEven returns correct boolean

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