Overview of Eclipse Lectures 1. Overview 2. Installing and Running 3. Building and Running Java Classes 4. Refactoring 5. Debugging 6. Testing with JUnit Lecture 3 7. Version Control with CVS 1 Module Road Map 1. Overview 2. Installing and Running 3. Building and Running Java Classes 4. Refactoring 5. Debugging Debug Perspective Debug Session Breakpoint Debug Views Breakpoint Types Evaluating and Displaying Expressions 6. Testing with JUnit 7. Version Control with CVS 2 1
Debugging» Debugging in Eclipse The Java Debugger Part of Eclipse Java Development Tools (JDT) More than System.out.printn( error ) Detects errors as code executes Correct errors as code executes Actions you can perform debugging include: Control Execution Set simple breakpoints Set conditional breakpoints Review and change variable values Hot code replace (feature new to JRE 1.4) 3 Debugging» Debug Perspective Threads and Monitor View Variable View Editor View Console View Tasks View 4 Outline View 2
Debugging» Simple Breakpoint Breakpoint Stops the execution of a program at the point Thread suspends at the location where the breakpoint is set Setting a breakpoint CTRL+Shift+B at current point in editor line Double click in editor s marker bar at current line 5 Debugging» Starting a Debugging Session Select Java class containing the following: main() method Resulting execution will pass breakpoint Select Run» Debug As» Java Application Or Select Debug As» Java Application from the drop-down menu on the Debug tool bar. 6 3
Debugging» Debug Session Execution suspends prior to the line with a breakpoint You can set multiple breakpoints 7 Debugging» Deleting Breakpoints Double click on the breakpoint in the editor 8 4
Debugging» Control Execution From Breakpoint Step Into or F5: For methods, execute method and suspend on first statement in the method For assignments, similar to Step Over For conditionals, similar to Step Over Step Over or F6 Execute next statement Step Return or F7 Resume execution to the end of the method on the next line after it was invoked 9 Debugging» Control Execution From Breakpoint Resume or F8 Continue execution until program ends or another breakpoint is reached Terminate Stops the current execution thread 10 5
Debugging» Variables and Fields To see the values bound to fields: Use Variables View Select variable in editor and select Inspect Select variable in editor and select Display 11 Debugging» Code Debugging in this Module public class Debug { private int something = 0; private Vector list = new Vector(); public void firstmethod(){ thirdmethod(something); something = something + 1; public void secondmethod(){ thirdmethod(something); something = something + 2; public void thirdmethod(int value){ something = something + value; public static void main(string[] args) { Debug debug = new Debug(); debug.firstmethod(); debug.secondmethod(); 12 6
Debugging» Variables View Shows all fields of instance where breakpoint occurred Select this to see all fields Select any field to see value If field is bound to an object, you can select Inspect from the menu to view its fields and values 13 Debugging» Changing Field Values To change field value: Select field in Variables view Select Change Variable Value from the menu Enter new value into Set Variable Value window Click OK 14 7
Debugging» Display View Displays the result of evaluating any expression in the current context Opens by: Selecting a field in the editor or Variables View and choosing Display Clicking on the Display tab 15 Debugging» Expressions View Remembers all objects you have inspected Displays the fields of the object You can see the values of the fields You can Inspect the fields Opens when: You Inspect an object You click on the Expressions tab 16 8
Debugging» Breakpoint View Lists all available breakpoints Can be used for manipulating breakpoints (through the views menu): Enabling Disabling Removing Also displays breakpoints properties Accessed like other debugging views 17 Debugging» Debug View Shows: Active threads Current stack frame when execution has stopped Previous stack frames Method and variables are shown in the editor for the selected frame Update in the editor updates the source 18 9
Debugging» Breakpoint Types Breakpoints can be set for the following Java entities: Line (simple breakpoint) Method Field (watchpoint) Java Exception Each breakpoint is set a different way and has different properties 19 Debugging» Method Breakpoints To set method breakpoint: Select method in the Outline View From context menu select Toggle Method Breakpoint To set breakpoint s properties: Select breakpoint in editor. From the context menu, select Breakpoint Properties.. from the context menu In the Properties dialog, Check Enabled to enable the breakpoint Check Hit Count to enable hit count. Breakpoint suspends execution of a thread the nth time it is hit, but never again, until it is re-enabled or the hit count is changed or disabled. Choose Enable condition to have breakpoint enabled only if the specified condition occurs. condition is 'true' option: Breakpoint stops if the condition evaluates to true. The expression provided must be a boolean expression. value of condition changes option: Breakpoint stops if result of the condition changes. 20 10
Debugging» Field Breakpoints Also known as watchpoint To set the watchpoint: Select field in the Outline View From context menu select Toggle Watchpoint To set watchpoint s properties: Select breakpoint in editor Select Breakpoint Properties.. from context menu Set properties as desired Access/modification, enable Execution suspended on access/modification of field 21 Debugging» Java Exception Breakpoint To Add Java Exception Point: Select Run» Add Java Exception Point from main menu Enter exception type Specify what triggers a breakpoint: Caught exception Uncaught exception Both 22 11
Debugging» How To Debug Here are simple steps for debugging in Eclipse: Set your breakpoints Hit a breakpoint during execution Walk/step through code to other breakpoints Follow along in editor Inspect/Display interesting fields Watch the Console for things to happen 23 Debugging» Summary You have learned: The views in the Debug Perspective Typical debug session How to use the Inspector About the different types of breakpoints How to set breakpoints How step around your code doing debugging 24 12
Debugging» Exercise 4 Set a breakpoint in the refactoredprintfield method of the class RefactoredClass that was refactored in Exercise 3. Start a debug session. What happens to the program execution? What do you see in the debug windows? 25 1. Overview 2. Installing and Running Module Road Map 3. Building and Running Java Classes 4. Refactoring 5. Debugging 6. Testing with JUnit What is JUnit? Where Does it Come From? Working with Test Cases Working with Test Suites JUnit Window 7. Version Control with CVS 26 13
What is JUnit? Regression testing framework Written by Erich Gamma and Kent Beck Used for unit testing in Java Open Source Released under IBM's CPL 27 Testing» Where Does JUnit Come From? JUnit s web site: http://junit.org/index.htm Eclipse includes JUnit Eclipse provides new GUI to run JUnit test cases and suites JDT tools include a plug-in that integrates JUnit into the Java IDE Allows you to define regression tests for your code and run them from the Java IDE. You can run your unit tests outside of Eclipse If you wish using TestRunner Using JUnit s Window 28 14
Testing» Eclipse JUnit Setup Eclipse preferences can be set in the JUnit Preferences window (Window» Preferences from the main menu. Expand Java in the Preferences window) For the most part you can leave the preferences alone Filters needed to identify packages, classes, or patterns that should not be shown in the stack trace of a test failure 29 Testing» JUnit Test Cases JUnit Test Cases Test case Runs multiple tests Implemented as subclass of TestCase Define instance variables that store the state of the tests in the class Initialize TestCase by overriding setup method Clean-up after test case is done by overriding teardown method The Test framework will invoke the setup and teardown methods. 30 15
Testing» Creating JUnit Test Cases in Eclipse Create a new package to contain your test case classes Add the JUnit JAR file to the project s buildpath 31 Testing» Creating JUnit Test Cases in Eclipse Select your testing package From the context menu select New» JUnit Test Case. This opens the New JUnit Test Case Wizard. Fill in the name of your test case in the Name field. Select the method stubs that you want Eclipse to generate This will create the corresponding class in your testing package 32 16
Testing» JUnit TestCase Template public class NewTestCase extends TestCase { public static void main(string[] args) ) { public NewTestCase(String arg0) { super(arg0); protected void setup() throws Exception { super.setup(); protected void teardown() throws Exception { super.teardown(); 33 Testing» Adding Tests to Test Cases Any method in a TestCase class is considered a test if it begins with the word test. You can write many tests (have many test methods) Each test method should use a variety of assert methods to perform tests on the state of its class. Assert methods are inherited 34 17
Testing» JUnit Assert Methods Assert methods include: assertequal(x,y) assertfalse(boolean) asserttrue(boolean) assertnull(object) assertnotnull(object) assetsame(firstobject, secondobject) assertnotsame(firstobject, secondobject) 35 Testing» Adding Two Tests to JUnit Test Case public class NewTestCase extends TestCase { public static void main(string[] args) ) { public NewTestCase(String arg0) { super(arg0); protected void setup() throws Exception { super.setup(); protected void teardown() throws Exception { super.teardown(); public void testcomparesucceed() { assertequals(0, 0); //this assertion will succeed public void testcomparefail() { assertequals(0, 1); //this assertion will fail 36 18
Testing» Running JUnit Test Case Select TestCase class From the Run menu select Run» Run As» JUnit Test This will run the tests in your TestCase class along with the setup and teardown methods You will then get a report in the JUnit window 37 Testing» JUnit Window Red indicates a test has failed You can see which test failed You can see the call trace leading to the failure If you wish to see the tests in TestCase click on the Hierarchy tab 38 19
Testing» JUnit Window You can see how many tests ran How many failures occurred You can see the details of the failure Errors occur when exceptions are thrown 39 Testing» Creating JUnit Test Suite Test Suite Runs multiple test cases or suites To create a TestSuite Select your testing package From the context menu select New» Other Then from the Wizard select Java» JUnit» JUnit Test Suite 40 20
Testing» Creating JUnit Test Suite Fill in the name of your TestSuite class Select the TestCases to include in your TestSuite 41 Testing» Unit Test Suite Template import com.test; import junit.framework.test; public class AllInclusiveTestSuite { public static Test suite() { TestSuite suite = new TestSuite("Test for com.test"); //$JUnit JUnit-BEGIN$ suite.addtestsuite(newtestcase.class)); suite.addtestsuite(secondtestcase.class)); //$JUnit JUnit-END$ return suite; 42 21
Testing» Running JUnit Test Suite Select TestSuite class From the Run menu select Run» Run As» JUnit Test This will run the test cases in your TestSuite class You will then get a report in the JUnit Window 43 Testing» JUnit Test Interface The JUnit classes TestCase and TestSuite both implement the JUnit Test interface Therefore, you can add JUnit TestSuites to other TestSuites public static Test suite() { TestSuite suite = new TestSuite("Test for testing"); //$JUnit-BEGIN$ suite.addtestsuite(firsttestcase.class); suite.addtestsuite(secondtestcase.class); suite.addtest(alltests.suite()); //$JUnit-END$ return suite; 44 22
Exercise 5 Create a JUnit test case class TestClass for the package csc517 of the project EgApp. Add a test method testboolean to the class TestClass. In the method testboolean, invoke the assert routine asserttrue with the argument 0 (FALSE). Run the test case. What do you see in the JUnit window? Now invoke the asserttrue routine with the argument 1 (TRUE). Run the test case. What is the output in the JUnit window? 45 23