How to run test cases on a list of slightly different jars?
Question
I have a list of jar files, all containing slightly different versions of the same system.
I want to execute a set of test cases on each jar file while being able to obtain the results for each jar (via RunListener or something like that).
I am a bit confused with the class loading problems that are implied.
How can I nicely do this ?
Solution
If you are using ant, the JUnit task takes a classpath.
<target name="test">
<junit ...">
<classpath>
<pathelement path="${test.jar.path}" />
</classpath>
...
</junit>
</target>
You can use the antcall task to call your test target repeatedly with a differed value for the test.jar.path property.
OTHER TIPS
If the jars maintain the same interface, then all you have to do is run each test with a slighly different classpath - each time with jars from another version.
If you're using Eclipse JUnit integration, just create N run configurations, in each one in the classpath tab specify required jars.
If you want to do it programmatically, then I suggest you start with empty classpath and use URLClassLoader, giving it a different set of jars each time.
Something like this:
URLClassloader ucl = new URLClassLoader( list of jars from version1 );
TestCase tc = ucl.loadClass("Your Test Case").newInstance();
tc.runTest();
ucl = new URLClassLoader( list of jars from version2 );
TestCase tc = ucl.loadClass("Your Test Case").newInstance();
tc.runTest();