JUnit 5 Assumptions Examples

By mkyong | Updated: September 17, 2019

Viewed: 2,949 (+90 pv/w)

Tags: assumption conditional test junit 5 unit test

This article shows you how to use JUnit 5 Assumptions to perform a conditional test execution.

Technologies used:

• Maven 3.6
• Java 8
• JUnit 5.5.2

1. Assumptions

1.1 If the assumeTrue() condition is true, then run the test, else aborting the test.

1.2 The assumingThat() is much more flexible, it allows part of the code to run as a conditional test.

package com.mkyong;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

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

public class AssumptionsTest {

    // Output: org.opentest4j.TestAbortedException: Assumption failed: assumption is not true
    @DisplayName("Run this if `assumeTrue` condition is true, else aborting this test")
    @Test
    void testOnlyOnDevEnvElseAbort() {
        assumeTrue("DEV".equals(System.getenv("APP_MODE")));
        assertEquals(2, 1 + 1);
    }

    // Output: org.opentest4j.TestAbortedException: Assumption failed: Aborting test: not on developer environment
    @DisplayName("Run this if `assumeTrue` condition is true, else aborting this test (Custom Message)")
    @Test
    void testOnlyOnDevEnvElseAbortWithCustomMsg() {
        assumeTrue("DEV".equals(System.getenv("APP_MODE")), () -> "Aborting test: not on developer environment");
        assertEquals(2, 1 + 1);
    }

    @Test
    void testAssumingThat() {

        // run these assertions always, just like normal test
        assertEquals(2, 1 + 1);

        assumingThat("DEV".equals(System.getenv("APP_MODE")),
                () -> {
                    // run this only if assumingThat condition is true
                    assertEquals(2, 1 + 1);
                });

        // run these assertions always, just like normal test
        assertEquals(2, 1 + 1);

    }

}

Output

Download Source Code

References

• JUnit 5 Official site
• JUnit 5 Assumptions JavaDoc