JUnit4 Survival Guide

by Michael Thomas

JUnit & TDD Home Page

This first section has the must know items to survive using JUnit.

Must Know ASAP

• Assert Test Methods
  • assertEquals(expected, actual) - uses the equals() method for objects.  Primitives uses the value as expected.
    also: assertEquals(description, expected, actual).
  • assertEquals(double expected, double actual, double delta) - expected values are considered equal if within the delta value.
    ex:
  • assertSame(expected, actual) - for objects only.
  • assertTrue(actual) - fails if actual is false.
  • assertFalse(actual) - fails if actual is true.
  • assertNull(actual) - fails if actual is not null.
  • assertNotNull(actual) - fails if actual is not null.
• Must haves for JUnit4:
  • Imports - 2 imports
    import static org.junit.Assert.*;
    import org.junit.Test;
  • Class Name - always follows the naming convention: <ClassName>Test
    ie: MyClassTest
  • Java Notation - using a Java notation of @Test before all test methods.
  • Test Methods - all methods that you want JUnit to run will follow these rules:
    • Visibility is: public
    • Return type is: void
    • Arguments: None!
    • Method names start with lower case "test"
  • Note: The order of running the methods can NOT be predicted!  Do not make test cases that rely on other methods running first!