Nicolas, thanks. I was one class off. I was looking at Main and AntMain
when I should have been looking at Launcher. Seeing the type names and the
main method threw me off. And this corroborates my brief follow-up that I
could be doing something with URLClassLoader. Better for me to try to
leverage Launcher though than reinvent that wheel.
Let me see how far I get with that.
I do have to take issue with the one point you make: "But If I were you, I
wouldn't bother trying to mimic Ant classloading in a unit test. The
important thing is to be sure that you run against the expected version of
Ant and Ivy."
First, this is not a unit test. It's an integration test or a functional
test, and if it doesn't emulate the real-life behavior in the wild, then
what use is it?
Even if we are treating this as a unit test, you can't really say that
inadvertently picking up everything in the parent ClassLoader is the
equivalent of mocking or stubbing services and components as one normally
does when creating pure unit tests. Consider that there could be a ton of
classes in the IDE's ClassLoader that have nothing whatsoever to do with
the Ant Project being executed.
And this brings me to my last concern. I have already encountered a problem
where some static functionality in some superfluous classes in the
IDE-inherited ClassLoader was causing the JUnit-invoked Project build to
fail.
Even so, to my mind, the uncontrolled success I'm seeing now is no less
troubling than the uncontrolled failure I was seeing then. If you're a
biologist conducting an experiment, you don't want to find out your
cultures were growing only because the Petri dish got contaminated.
On Sat, Jul 21, 2012 at 6:10 AM, Nicolas Lalevée <nicolas.lale...@hibnet.org
> wrote:
> Hi Mitch,
>
> Le 21 juil. 2012 à 07:37, Mitch Gitman a écrit :
>
> > Technically, this message is better suited for the ant-user list, but I'm
> > thinking I'm more apt to get an answer on this list. (I'm also thinking
> > this is the better place for me to cash in some chits for my having
> > submitted patches for three Ivy issues I mentioned recently on this list.
> > Subject: "extends and buildlist on 2.3.0-rc1....")
>
> I am intended to give it a look very soon, I have seen all the activity
> you have done, I don't want to waste it :)
>
> > Here's my problem. I'm trying to do a JUnit test of some Ivy
> functionality
> > (actually, relating to the aforementioned Ivy bugs) by programmatically
> > creating and executing an Ant Project object. Everything runs just fine.
> > I'm able to execute targets and even tie in a BuildListener and a
> > BuildLogger to tap into output and error and check if the build failed.
> >
> > The problem is, everything works a little too well. Take a look at the
> > following example build.xml:
> > <project xmlns:ivy="antlib:org.apache.ivy.ant" name="resolve-test"
> > default="build">
> >
> > <target name="build">
> > <ivy:settings file="ivysettings.xml" />
> > <ivy:resolve ... />
> > </target>
> > </project>
> >
> > I've abbreviated the ivy:resolve call, but take it from me that
> everything
> > works, including running the test directly from within an IDE. It
> > shouldn't. Nowhere am I specifying the classpath containing the JAR for
> Ivy
> > itself. Nowhere am I even doing the taskdef for Ivy.
>
> In fact, just by writing xmlns:ivy="antlib:org.apache.ivy.ant", Ant does a
> lookup for the Ivy tasks. It will look for org/apache/ivy/ant/antlib.xml in
> the classpath, derived from the uri definition of the xmlns.
> So I guess that in your IDE, it works since you have Ivy in your classpath.
>
> > And in fact, if I run this build.xml straight from the command line, it
> > fails like you would expect:
> > Problem: failed to create task or type antlib:org.apache.ivy.ant:settings
> > ...
>
> This means that the Ivy jar is neither in the Ant classpath
> ($ANT_HOME/lib/), nor in your ant user lib directory ($HOME/.ant/lib).
>
> > I can only think that the key method I want to take advantage of is this
> in
> > Project:
> > public void setCoreLoader(ClassLoader coreLoader) {
> > this.coreLoader = coreLoader;
> > }
> >
> > What's interesting is that the command-line entry point for Ant in
> > org.apache.tools.ant.Main ends up passing null to setCoreLoader, in which
> > case "the parent classloader should be used," according to the method's
> > Javadoc. At this point, I go take a look at the scripts that launch Ant
> and
> > my eyes get blurry. But I believe what I want to do is manually
> construct a
> > ClassLoader as if I were running "java -cp ..." with the contents of
> Ant's
> > lib directory. (I'm showing my ignorance of ClassLoaders here, I
> realize.)
> > Perhaps someone can point me to an elegant way to accomplish that.
>
> On the command line, the jvm is given only the ant-launcher.jar, it will
> be the content of the system classloader.
> Then in org.apache.tools.ant.launch.Launcher.run(String[]), we can see the
> ant Main class is loaded and launched with this classloader:
> new URLClassLoader(jars, Launcher.class.getClassLoader());
> The system is the parent, the jars listed from $ANT_HOME/lib/,
> $HOME/.ant/lib and other jars from the jvm (tools.jar for instance) will be
> the content of that classloader. This last classloader will be the parent
> classloader of the Project instance.
>
> Now in your IDE, you launch your unit test with every jar listed in your
> classpath, so every thing is already available in the system classlaoder.
> And that system classloader is the parent classloader of the Project
> instance. So lookups works.
> So if you want thing to not work, you'll have to build indeed an
> URLClassloader, just like org.apache.tools.ant.launch.Launcher.run does.
> But without any parent classlaoder, otherwise you end up again with the
> full classpath of your project in the IDE.
>
> But If I were you, I wouldn't bother trying to mimic Ant classloading in a
> unit test. The important thing is to be sure that you run against the
> expected version of Ant and Ivy. And relying on the content of a
> $HOME/.ant/lib is quite unsafe.
>
> Nicolas
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscr...@ant.apache.org
> For additional commands, e-mail: dev-h...@ant.apache.org
>
>
