Objectives

• Build and populate a directory structure for developing a simple project consisting of a single Java archive.
• Test our implementation and look at report.
• Add/remove failures to tests.

Steps

1. Set a few logical variables to represent root directories. For the purposes of the follow-on steps, PROJECT_BASEDIR is the root directory for this exercise. In the example below, the user has chosen a directory of $HOME/proj/784/exercises to be the root directory for all class exercises and named the root directory for this project "ex1". An alternative for CLASS_HOME might be c:/jhu/784.

   $ export CLASS_HOME=$HOME/proj/784
   $ export PROJECT_BASEDIR=$CLASS_HOME/exercises/ex1
   $ mkdir -p $PROJECT_BASEDIR

2. Create project directory structure. In this example, the developer used $HOME/proj/784 for all work in this class.

   $PROJECT_BASEDIR
       +---/src/main/java/myorg/mypackage/ex1
       +---/src/test/java/myorg/mypackage/ex1
       +---/target/classes
       +---/target/test-classes
       +---/target/test-reports

3. Add the following Java implementation class to PROJECT_BASEDIR/src/main/java/myorg/mypackage/ex1/App.java

   package myorg.mypackage.ex1;
   
   public class App {
       public int returnOne() { 
           System.out.println( "Here's One!" );
           return 1; 
       }
   
       public static void main( String[] args ) {
           System.out.println( "Hello World!" );
       }
   }

4. Add the following Java test class to PROJECT_BASEDIR/src/test/java/myorg/mypackage/ex1/AppTest.java

   package myorg.mypackage.ex1;
   
   import static org.junit.Assert.*;
   
   import org.apache.commons.logging.Log;
   import org.apache.commons.logging.LogFactory;
   import org.junit.Test;
   
   /**
    * Unit test for simple App.
    */
   public class AppTest {
       private static Log log = LogFactory.getLog(AppTest.class);
   
       @Test
       public void testApp() {
           System.out.println("testApp");
           App app = new App();
           assertTrue("app didn't return 1", app.returnOne() == 1);
       }
   }

5. Compile the application and place it in target/ex1.jar. The compiled classes will go in target/classes.

   > javac src/main/java/myorg/mypackage/ex1/App.java -d target/classes
   > jar cvf target/ex1.jar -C target/classes .
   added manifest
   adding: myorg/(in = 0) (out= 0)(stored 0%)
   adding: myorg/mypackage/(in = 0) (out= 0)(stored 0%)
   adding: myorg/mypackage/ex1/(in = 0) (out= 0)(stored 0%)
   adding: myorg/mypackage/ex1/App.class(in = 519) (out= 350)(deflated 32%)
   
   > jar tf target/ex1.jar
   META-INF/
   META-INF/MANIFEST.MF
   myorg/
   myorg/mypackage/
   myorg/mypackage/ex1/
   myorg/mypackage/ex1/App.class

6. Compile the JUnit test and place the compiled tests in target/test-classes.

   > export JUNIT_JAR=`cygpath --windows c:/jhu/repository/junit/junit/4.10/junit-4.10.jar
   > javac -classpath "target/ex1.jar;$JUNIT_JAR" \
   src/test/java/myorg/mypackage/ex1/AppTest.java -d target/test-classes
   
   target/
       +---classes/myorg/mypackage/ex1/App.class
       +---test-classes/myorg/mypackage/ex1/AppTest.class
       +---test-reports
       +---ex1.jar

7. Run the JUnit test framework.

   > java -classpath "target/ex1.jar;$JUNIT_JAR;target/test-classes" \
   org.junit.runner.JUnitCore myorg.mypackage.ex1.AppTest
   .testApp
   Here's One!
   
   Time: 0.013
   
   OK (1 test)

8. Change add/remove a test that will fail, re-compile the test class and re-run.

       //AppTest.java
       @Test
       public void testFail() {
           System.out.println("testFail");
           App app = new App();
           assertTrue("app didn't return 0", app.returnOne() == 0);
       }
   
   .testApp
   Here's One!
   .testFail
   Here's One!
   F
   Time: 0.015
   There was 1 failure:
   1) testFail(myorg.mypackage.ex1.AppTest)junit.framework.AssertionFailedError: app didn't return 0
           at myorg.mypackage.ex1.AppTest.testFail(AppTest.java:29)
           at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
           at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
           at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   
   FAILURES!!!
   Tests run: 2,  Failures: 1,  Errors: 0

Summary

In this part of the exercise you setup, built, and tested a sample project with only command-line commands. You did this to help show what higher level tools will need to do as well. Even though the command line provides clarity, it doesn't scale and shell scripts aren't generally portable and optimized (wrong tool for the job). Hopefully, after going through this, you have an understanding of the low level structure and usecases and are now interested adding a build environment.