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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 .jar(s) downloaded somewhere on your computer, 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).

optional: 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 OG0 .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

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 the shell-alias alias junit java -jar /Library/JUnit/junit-platform-console-standalone-version.jar -cp .::/Library/JUnit/junit-platform-console-standalone-version.jar --select-class
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:) Heck, 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. (This is probably optional, unless your methods mutate shared state, in which case it's necessary to keep one test from influencing some different separate test. You don't want changing the order of tests, or adding new intermediate tests, to change the outcome.)

This page licensed CC-BY 4.0 Ian Barland
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