assumingThat for conditional assertions in JUnit - Test Execution Trace

Test Overview

This test demonstrates how to use assumingThat in JUnit to run assertions only when a specific condition is true. It verifies that the assertion inside assumingThat runs only if the condition matches.

Test Code - JUnit 5

JUnit

import static org.junit.jupiter.api.Assumptions.assumingThat;
import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.Test;

public class ConditionalAssertionTest {

    @Test
    void testConditionalAssertion() {
        String environment = "DEV";

        assumingThat(environment.equals("DEV"), () -> {
            assertEquals(5, 2 + 3, "Sum should be 5 in DEV environment");
        });

        assumingThat(environment.equals("PROD"), () -> {
            assertEquals(10, 5 + 5, "Sum should be 10 in PROD environment");
        });
    }
}

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts	JUnit test runner initialized	-	PASS
2	Test method 'testConditionalAssertion' invoked	Variable 'environment' set to 'DEV'	-	PASS
3	Check condition environment.equals("DEV") for assumingThat	Condition is true	Run assertion assertEquals(5, 2 + 3)	PASS
4	Assertion inside assumingThat for DEV environment executed	2 + 3 equals 5	assertEquals(5, 5) passes	PASS
5	Check condition environment.equals("PROD") for assumingThat	Condition is false	Assertion inside assumingThat skipped	PASS
6	Test method completes	No failures	-	PASS

Failure Scenario

Failing Condition: The assertion inside assumingThat runs when the condition is true but the assertion fails

Execution Trace Quiz - 3 Questions

What happens to the assertion inside assumingThat when the condition is false?

A The assertion runs and can pass or fail

B The test fails immediately

C The assertion is skipped and not executed

D The test runner throws an exception

Key Result

Use assumingThat to conditionally run assertions based on runtime conditions, helping tests adapt to different environments or states without failing unnecessarily.