Junit unit testing concepts (test language Java)

A unit testing concepts

1. What is unit testing

• Unit testing is to write test for the smallest functional unit code
• Java program smallest functional unit approach
• Unit testing is to test for a single Java method

2. Use disadvantage main () Test Method

• Only one main () method, the test code can not be separated
• No print out the test results and expected results
  such as: expected: 63533, but actual: 89653
• So then you need a testing framework to help us write a test

3. The benefits of unit testing

• A single method to ensure normal operation
• If a method of modifying the code only needs to be ensured by the corresponding unit test
• Code itself can be used as test sample code
• All tests can be automated and access to report

4. JUnit Introduction

• JUnit is an open source unit testing framework for the Java language
• Designed specifically for the Java language, the most widely used
• JUnit is the de facto standard unit testing framework

4. JUnit Features

• Use the assertion (Assertion) test results expected
• It can easily organize and run tests
• You can easily view the test results
• Common IDE (e.g. Eclipse) are integrated JUnit
• It can be easily integrated into Maven

5. JUnit design

• TestCase: a TestCase represents a test
• TestSuite: a TestSuite contains a set of TestCase, represents a group of test
• TestFixture: a TestFixture represents a test environment
• TestResult: for the collection of test results
• TestRunner: used to run tests
• TestListener: used to monitor the testing process, to collect test data
• Assert: to assert the test results are correct

6. Assert assertion

• Assert equal: assertEquals (expected value, the test results)
• Assertion arrays are equal: assertArrayEquals ((1,2,3), x)
• Float assert equal: assertEquals (3.1412, X, 0.00001)
• Assertion is null: assertNull (x)
• Asserted true / false: assertTrue (x> 0) assertFalse (x <0)
• Other: assertNotEquals / assertNotNull

7. Junit unit test point to note

• A TestCase contains a set of related test methods
• Assert assertion using the test results (note float assertEquals to specify delta)
• Each test method must be totally independent
• It must be very simple test code
• You can not write tests for testing code
• Testing needs to cover a variety of input conditions, especially boundary conditions