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From Christopher Schultz <>
Subject Re: Need guidance for writing unit tests for 55317
Date Wed, 21 Aug 2013 13:48:52 GMT

On 8/20/13 8:24 PM, Nick Williams wrote:
> I ran in to a roadblock with this idea. Part of the byte code of a
> class includes the fully-qualified class name. If I create a class,
> say UnweavedClass, and replace its byte code in my fake transformer
> with that of another class, the FQCN changes. This results in a
> NoClassDefFoundError because the class loader is looking for
> UnweavenClass in be in the byte code when really some other class
> is.
> My backup idea is slightly less clean but, IMO, still more clean than
> adding ASM as a test-time dependency and trying to figure all of that
> out. I locally compiled fake "weaved" versions of the UnweavedClass
> (with the modified behavior) and then translated each version into a
> Java byte array definition. (These are extremely simple on-line,
> one-method classes, so the byte arrays are relatively short.) I then
> simply embedded the byte array definitions as static final byte[]
> fields the test class and replaced the byte code in my fake
> transformer with those embedded fields' content. I've tested this and
> it works great.

Any reason not to simply compile some .java source into a .class file
and read it from the disk instead of shoving it into a byte array?
There's nothing stopping you from doing an offline-compile of a .java
file into a .class file and committing both to svn. You don't have to
compile the .java source as part of the test -- just load it off disk as
part of the test.

This will allow easier inspection of the .class file, and not be such a
pain in the neck to change the bytecode if necessary.


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