Why Not Just Use System.out.println() for Unit Testing?

JUnit Questions and Answers

(Continued from previous question...)

Why Not Just Use System.out.println() for Unit Testing?

Inserting debug statements into code is a low-tech method for debugging it. It usually requires that output be scanned manually every time the program is run to ensure that the code is doing what's expected.

It generally takes less time in the long run to codify expectations in the form of an automated JUnit test that retains its value over time. If it's difficult to write a test to assert expectations, the tests may be telling you that shorter and more cohesive methods would improve your design.

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Other Interview Questions

• What Is JUnit?
• Who Should Use JUnit, Developers or Testers?
• Why Do You Use JUnit to Test Your Code?
• Do You Know the Book "JUnit Recipes: Practical Methods for Programmer Testing"?
• Do You Know the Book "JUnit in Action"?
• Where Do You Download JUnit?
• How Do You Install JUnit?
• What Articles Have You Read about JUnit?
• How To Wirte a Simple JUnit Test Class?
• How To Compile a JUnit Test Class?
• How To Run a JUnit Test Class?
• What CLASSPATH Settings Are Needed to Run JUnit?
• How Do I Run JUnit Tests from Command Window?
• How Do You Uninstall JUnit?
• How To Write a JUnit Test Method?
• Can You Provide a List of Assertion Methods Supported by JUnit 4.4?
• What Happens If a JUnit Test Method Is Declared as "private"?
• What Happens If a JUnit Test Method Is Declared to Return "String"?
• Why Does Poeple Import org.junit.Assert Statically?
• How To Group Multiple Test Classes into a Suite in JUnit 4.4?
• How To Run a "@Suite.SuiteClasses" Class in JUnit 4.4?
• What Is the "@SuiteClasses" Annotation?
• Why Not Just Use a Debugger for Unit Testing?
• Why Not Just Write a main() Method for Unit Testing?
• Why Not Just Use System.out.println() for Unit Testing?
• Under What Conditions Should You Test set() and get() Methods?
• Under What Conditions Should You Not Test Get() and Set() Methods?
• Do You Need to Write a Test Class for Every Class That Need to Be Tested?
• What Is JUnit TestCase?
• What Is JUnit TestSuite?
• How Many Test Runners Are Supported in JUnit 3.8?
• What Are JUnit 3.8 Naming Conventions?
• How To Write a Single Class to Define Multiple Tests and Run Them?
• How to Run Your JUnit 4.4 Tests with a JUnit 3.8 Runner?
• Can You Write a Simple Class for JUnit Testing in 1 Minute?
• Can You Write a JUnit Test Case Class in 2 Minutes?
• Can You Write a JUnit Test Suite in 2 Minutes?
• Where Should You Place Test Classes?
• How Do You Test a "protected" Method?
• How Do You Test a "private" Method?
• Can You Write a JUnit Test Case Class in 10 Minutes?
• Can You Explain a Sample JUnit Test Case Class?
• Do You Need to Write a main() Method in a JUnit Test Case Class?
• How To Group Test Cases Class using JUnit TestSuite?
• Can You Write a JUnit 4.4 Test Class Template in 2 Minutes?
• Can You Explain the Life Cycle of a JUnit 4.4 Test Class?
• How To Write Setup Code to Run Once for All Tests in a Test Class?
• Can You Write a JUnit 3.8 Test Class Template in 2 Minutes?
• Can You Explain the Life Cycle of a JUnit 3.8 Test Case Class?
• What Is a JUnit Test Fixture?
• Can You Create Tests without Using a Common Test Fixture?
• How Create a Test Fixture to Be Shared by All Tests in a Test Class?
• How To Destroy a JUnit Test Fixture?
• When Do You Need to Write an @After Method?
• When Should Unit Tests Should Be Written In Development Cycle?
• How Do You Launch a Debugger When a Test Fails?
• How Do You Run JUnit Using Ant?
• How Do You Run All Test Classes without Managing a TestSuite Explicitly?
• How Do You Test an Expected Exception with JUnit?
• How To Use the "expected" Parameter Supported by the "@Test" Annotation?
• How Do You Test an Unexpected Exception with JUnit?
• What Happens If a Test Method Throws an Exception?
• Why Do I See "Unknown Source" in the Stack Trace of a Failed Test?
• How Do You Test a Method That Doesn't Return Anything?
• When Objects Are Garbage Collected After a Test Is Executed?
• What Is Java "assert" Statement?
• How To Test Programs Thats Use Java "assert" Statements?
• Should You Run JUnit Tests with Java Assertion Disabled?
• What Happens If You Run JUnit Tests with Java Assertion Enabled?
• Why Does JUnit Only Report the First Failed Assertion in a Single Test?
• Do You Have To Write a Test for Everything?
• How Often Should You Run Your JUnit Tests?
• What Do You Do When a Defect Is Reported?
• How simple is 'too simple to break'?
• How To Verify the JUnit Plugin in Eclipse?
• How To Create Test Class in Eclipse?
• How to Run a JUnit Test Case in Eclipse?
• Can You Describe Steps of Creating Test Case Classes in Eclipse?
• How to creating a Test Suite using JUnit in Eclipse?
• How Do You Use Ant to Create HTML Test Reports?
• How Do You Test Classes That Must Be Run in a J2EE Container?
• Can You Explain the Exception: "No runnable methods"?