how to run JUnit

Many IDEs have JUnit built-in (e.g. eclipse and BlueJ). However, if you get a compile-time error about “class junit.framework.TestCase not found”, it means that the following two steps haven't both been done: (a) you have JUnit .jars downloaded, and (b) your CLASSPATH includes it. You can do these two thing from inside your IDE, or from the command-line (which this page is all about).

Note: It is not a requirement to use JUnit for our ITEC380 project. You can strip out the mentions of the JUnit classes, and write your own:
    void assertEquals( Object actual,  Object expected ) {
      if (!actual.equals(expected)) {
        System.err.printf("assertion failed:\nExpect: %s\nActual: %s\n", expected.toString(), actual.toString() );
        }
      }
  

IDE-specific instructions

One student reports: After downloading the two JUnit .jar files (below), I added them to the reference library for the project that I added the U0 .jar file to originally. Then I could right click and select Run As and select JUnit Test. I could run individual test methods/classes, or specify running all tests within the entire .jar file.

If somebody sends me (links to) good instructions for running/installing JUnit from inside other IDEs, send me a link and I'll put it here.

Command-line

Installing JUnit

Download the two necessary jar files (junit and hamcrest-core). Store them in a fairly-general place within your Java development/coding directories (intended to be shared by all your Java projects). I use /Users/username/dev/ (where /Users/ is specific to MacOS, and dev is a directory I made myself).
Either set your classpath to explicitly include the jars (e.g. setenv CLASSPATH .::~/Src/junit-4.12.jar:hamcrest-core-1.3.jar), or pass that to java/javac (e.g. javac -classpath .::/Users/username/dev/junit-4.12.jar:/Users/username/dev/hamcrest-core-1.3.jar MyFile.java).
Compile your test-classes with javac. (If they compile, you're good.)

Invoking JUnit tests yourself

JUnit test-classes don't have a main. So instead, we can trigger the tests by running org.junit.runner.JUnitCore's main, passing it the name(s) of what test-classes to run:

java org.junit.runner.JUnitCore MyTestClass

We can simplify this in a couple ways:

I like alias junit java --class-path :~/dev/junit-4.12.jar:~/dev/hamcrest-core-1.3.jar org.junit.runner.JUnitCore
Alternately, you can code the above method-call inside your own function: public static void main(String... __) { org.junit.runner.JUnitCore.main("MyClassTest"); }. (This may require having “.” in your CLASSPATH.)

(Related:) Rather than calling JUnitCore.main, you could just call specfic test-methods yourself:

    public static void main(String... args) {
        ExprTest t = new ExprTest();
        t.setUp();  t.testMethod1();  t.tearDown();
        t.setUp();  t.testMethod2();  t.tearDown();
        }

It's expected-protocol to call setUp/tearDown before/after calling each test-method. (If your methods modify state, then this might be essential.)

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