How to compile single class dependency in gradle outside the main project - gradle

Question

I have a gradle project that contains only Selenium/TestNG test classes. They are executed against a deployed war application. All works fine and now I'm adding a java utility that will query the test base and print list of tests that belong to a given TestNG group. The utility should be compiled and executed separate from the main project, as users may want to query the test base before test execution.
I added the following to build.gradle:
task listgroups(dependsOn:'buildUtil' ) <<{
ant.java(classname: 'util.TestGroupScanner', fork: true,
classpath: "src/test/java")
}
task buildUtil {
compile {
source = "src/test/java/util"
}
}
However, when calling listgroups task, I'm getting the following error:
C:\console-bg1>g listgroups
FAILURE: Build failed with an exception.
(...)
* What went wrong:
A problem occurred evaluating root project 'console-bg1'.
> Could not find method compile() for arguments [build_4emu7duna2isgubc1k8uts8k9
8$_run_closure6_closure11#d210ab] on root project 'console-bg1'.
I'm not sure how to resolve this issue and needless to say, haven't found an answer online so far. Any pointers appreciated.

Answer 1

The problem is in the buildUtil task, as the error suggests. The buildUtil declares a compile closure, but such closure does not exist for the default task.
Let me try to clarify what your setup is. The util.TestGroupScanner source is in the src/test/java/util directory, which you want to compile separately from other source (presumably src/main/java and src/test/java). The buildUtil task is supposed to compile sources in src/test/java/util, and the listgroups task executes the scanner utility on sources src/test/java folder.
In this case, I'd suggest you declare a new source set for your utility sources, like this:
sourceSets {
util {
java {
srcDir 'src/test/java/util'
}
}
}
This will automatically create a compile task called compileUtilJava for you, that will compile those sources. I also think you'll want to include utility classes in the classpath when executing your tool, which can be retrieved by sourceSets.util.output.classesDir. So now your listgroups task will look like:
task listgroups(dependsOn: 'compileUtilJava' ) <<{
ant.java(classname: 'util.TestGroupScanner', fork: true,
classpath: "src/test/java:" + sourceSets.util.output.classesDir)
}
One thing I have noticed about your setup, is that src/test/java/util source folder is nested under src/test/java. Gradle will assume src/test/java to be the default folder for your project test, and will therefore automatically include it, and all of its children when running tests. Since you want to keep your utility folder separate from the default setup, I would recommend you put it in src/testutil/java, to avoid any clashes. If you do, don't forget to update the sourceSets setup above with the correct source path.

Answer 2

To solve this with gradle, I suggest to create a specific sourceset for your util class and add a task of type JavaExec that executes this class for printing your testng groups. Have a look at the following snippet:
apply plugin:'java'
...
...
configurations{
testUtilCompile.extendsFrom testCompile
}
...
...
sourceSets{
testUtil{
java {
srcDir "src/test/java"
include "util/**"
}
}
}
task printGroups(type:JavaExec){
main = "util.TestGroupScanner"
classpath = sourceSets.testUtil.runtimeClasspath
}
regards,
René