Unit Testing with JUnit

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Unit Testing with JUnit

• Dan Fleck
• Fall 2007
• (For both CS211 and 421
• two birds one lecture! -)

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What is Unit Testing?

• A procedure to validate individual units of
  Source Code
• Example A procedure, method or class
• Validating each individual piece reduces errors
  when integrating the pieces together later

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Automated Unit Tests with JUnit

• Junit is a unit testing framework for Java
• Allows you to write unit tests in Java using a
  simple interface
• Automated testing enables running and rerunning
  tests very easily and quickly

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An example unit test

• public void testCellChangePropagates()
  Spreadsheet sheet
• new Spreadsheet()
• sheet.put("A1", "5")
• sheet.put("A2", "A1")
• sheet.put("A1", "10")
• assertEquals("10",sheet.get("A2"))

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Junit with Netbeans

1. New File
2. Choose file type Junit
3. Choose Test for Existing Class
4. Junit test with all stubs created for that class
5. Fill in the individual tests
6. Run Tests (Netbeans options)

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Coverage Analysis

• Determining which lines of code your tests have
  exercised and which they have not
• Allows you to detect if your unit tests (or
  system tests) are adequately covering all
  possibilities or not
• This is just one way to test

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Coverage Analysis with Netbeans

• Install Unit Test Code Coverage Viewer module
• Write a Unit Test
• Run test and view highlighted code

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A simple test to dynamically cover your code

• public void testMain()
• SuDoku sFrame new SuDoku()
• while (sFrame.isDisplayable())
• try
• Thread.sleep(100)
• catch (Exception e)
• e.printStackTrace()
• Assert.assertEquals(true,true)

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Summary

• Unit tests can help test the details of your
  program
• Automated unit tests provide constant visibility
  and easy retesting
• Test coverage supplies valuable information when
  running both unit tests and system tests