@CsvSource for inline CSV data in JUnit - Test Execution Trace

Test Overview

This test uses JUnit's @CsvSource to run the same test method multiple times with different inline CSV data. It verifies that the sum of two numbers equals the expected result.

Test Code - JUnit 5

JUnit

import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.CsvSource;
import static org.junit.jupiter.api.Assertions.assertEquals;

public class CalculatorTest {

    @ParameterizedTest
    @CsvSource({
        "1, 2, 3",
        "4, 5, 9",
        "10, 20, 30"
    })
    void testAddition(int a, int b, int expectedSum) {
        int actualSum = a + b;
        assertEquals(expectedSum, actualSum, "Sum should match expected value");
    }
}

Execution Trace - 3 Steps

Step	Action	System State	Assertion	Result
1	Test starts with first CSV data set (1, 2, 3)	JUnit test runner initializes test method with parameters a=1, b=2, expectedSum=3	assertEquals(3, 1 + 2)	PASS
2	Test runs with second CSV data set (4, 5, 9)	JUnit test runner initializes test method with parameters a=4, b=5, expectedSum=9	assertEquals(9, 4 + 5)	PASS
3	Test runs with third CSV data set (10, 20, 30)	JUnit test runner initializes test method with parameters a=10, b=20, expectedSum=30	assertEquals(30, 10 + 20)	PASS

Failure Scenario

Failing Condition: Expected sum does not match actual sum for any CSV data set

Execution Trace Quiz - 3 Questions

What does the @CsvSource annotation do in this test?

A Runs the test only once with default values

B Provides multiple sets of input data inline for the test method

C Reads CSV data from an external file

D Skips the test if CSV data is missing

Key Result

Using @CsvSource allows running the same test logic with multiple input values easily, improving test coverage and reducing code duplication.