@CsvFileSource for external CSV in JUnit - Test Execution Trace

Test Overview

This test reads multiple sets of input data from an external CSV file using @CsvFileSource. It verifies that the sum of two numbers equals the expected result for each data row.

Test Code - JUnit 5

JUnit

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

public class CalculatorTest {

    @ParameterizedTest
    @CsvFileSource(resources = "/data/sum-data.csv", numLinesToSkip = 1)
    void testSum(int a, int b, int expectedSum) {
        int actualSum = a + b;
        assertEquals(expectedSum, actualSum, () -> String.format("Sum of %d and %d should be %d", a, b, expectedSum));
    }
}

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test runner starts and loads the test class CalculatorTest	JUnit test environment initialized	-	PASS
2	Reads the CSV file '/data/sum-data.csv' skipping the header line	CSV file content loaded: rows of integers for a, b, expectedSum	-	PASS
3	Executes testSum with first data row (a=1, b=2, expectedSum=3)	Test method invoked with parameters (1, 2, 3)	Check if 1 + 2 equals 3	PASS
4	Executes testSum with second data row (a=5, b=7, expectedSum=12)	Test method invoked with parameters (5, 7, 12)	Check if 5 + 7 equals 12	PASS
5	Executes testSum with third data row (a=10, b=15, expectedSum=25)	Test method invoked with parameters (10, 15, 25)	Check if 10 + 15 equals 25	PASS
6	All parameterized test cases complete	Test report generated showing all tests passed	-	PASS

Failure Scenario

Failing Condition: CSV file path is incorrect or file is missing

Execution Trace Quiz - 3 Questions

What does the @CsvFileSource annotation do in this test?

A It provides test data from an external CSV file

B It writes test results to a CSV file

C It skips the test if the CSV file is missing

D It generates random test data

Key Result

Using @CsvFileSource allows easy testing of multiple input sets from an external CSV file, making tests cleaner and more maintainable.