CSCI-1320 Lab: Unit Tests for MathOperations Class

Purpose Statement

In this lab, we will practice creating unit tests with JUnit, using our MathOperations class from the previous week's lab. Then, we will add a new method using test driven development principles.

Instructions

Part 1: Set up JUnit

Follow the instructions here to install and configure JUnit 4.

Part 2: Create Unit Tests for MathOperations

• Create a new copy of MathOperations.java in the src folder of your project, and copy over the code from last week.
• Edit the test file for MathOperations, and create a unit test for each method in MathOperations. Each unit test should contain 2-3 asserts checking different values for the method

For example, to test MathOperations.addNumbers, you could write a test like this:

                    @Test
                    public void testAddNumbers() {
                        assertEquals(MathOperations.addNumbers(2,3), 5);  // Checks that addNumbers(2,3) returns 5
                        assertEquals(MathOperations.addNumbers(5, -2), 3);  // Checks that addNumbers(5,-2) returns 3
                    }
                

Hint: for testing doubles with many digits, you can use Math.round to round off the values for easy comparison.

• Once each test is written, run the tests to make sure your code passes the tests.

Part 3: Test Driven Development

Now, let's practice test driven development. Remember that the idea is to create a unit test for a new method first (Red), and then write the code so that the test passes (Green).

Paste the following code into your MathOperationsTest.java file:

                @Test
                public void testCelciusToFahrenheit() {
                    assertEquals(MathOperations.celciusToFahrenheit(0), 32);
                    assertEquals(MathOperations.celciusToFahrenheit(100), 212);
                }

            

Now, write a celciusToFahrenheit method that will make the test pass! (Hint: the formula is the reverse of the Fahrenheit to Celcius formula we used last week.)

Part 3: Submission

Submit both MathOperations.java and MathOperationsTest.java via Canvas by the due date. Make sure you are submitting this week's versions from your Project src folder!