Gradle milestone 4/5 fails in tests with plugin instantiation exception - build

Question

I have pretty sophisticated build using gradle - with a number of own gradle plugins.. The plugins are fully unit-tested, but as of Gradle-1.0-milestone-4 it seems that the plugins cannot be instantiated from within unit tests. I followed the standard gradle approach for that (taken from http://gradle.org/current/docs/userguide/custom_plugins.html):
class GreetingPluginTest {
#Test
public void greeterPluginAddsGreetingTaskToProject() {
Project project = ProjectBuilder.builder().build()
project.apply plugin: 'greeting'
assertTrue(project.tasks.hello instanceof GreetingTask)
}
}
When I run my tests with gradle 1.0-milestone-3, they all work fine (I just use the gradle binary from milestone-3 and all is fine)....
In milestone-4/5 I got such error as below. It seems that gradle uses different classloader internally to load classes, but how can I make it use the right one????
Error:
org.gradle.api.plugins.PluginInstantiationException: Could not find implementation class 'null' for plugin 'polidea-project-configuration' specified in file:/Users/potiuk/Documents/workspace/PolideaBuildPlugin/bin/META-INF/gradle-plugins/polidea-project-configuration.properties.
at org.gradle.api.internal.plugins.DefaultPluginRegistry.getTypeForId(DefaultPluginRegistry.java:102)
at org.gradle.api.internal.plugins.DefaultPluginRegistry.getTypeForId(DefaultPluginRegistry.java:76)
at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.getTypeForId(DefaultProjectsPluginContainer.java:102)
at org.gradle.api.internal.plugins.DefaultProjectsPluginContainer.apply(DefaultProjectsPluginContainer.java:37)
at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.applyPlugin(DefaultObjectConfigurationAction.java:101)
at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.access$200(DefaultObjectConfigurationAction.java:32)
at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction$3.run(DefaultObjectConfigurationAction.java:72)
at org.gradle.api.internal.plugins.DefaultObjectConfigurationAction.execute(DefaultObjectConfigurationAction.java:114)
at org.gradle.api.internal.project.AbstractProject.apply(AbstractProject.java:841)
at org.gradle.api.Project$apply.call(Unknown Source)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:42)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
at pl.polidea.gradle.BaseTaskTest.getProject(BaseTaskTest.groovy:14)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce.invoke(PogoMetaMethodSite.java:267)
at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite.callCurrent(PogoMetaMethodSite.java:52)
at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallCurrent(CallSiteArray.java:46)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:133)
at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:137)
at pl.polidea.gradle.TestBasicBuildTasks.testBuildTasksAvailable(TestBasicBuildTasks.groovy:11)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at junit.framework.TestCase.runTest(TestCase.java:168)
at junit.framework.TestCase.runBare(TestCase.java:134)
at junit.framework.TestResult$1.protect(TestResult.java:110)
at junit.framework.TestResult.runProtected(TestResult.java:128)
at junit.framework.TestResult.run(TestResult.java:113)
at junit.framework.TestCase.run(TestCase.java:124)
at junit.framework.TestSuite.runTest(TestSuite.java:243)
at junit.framework.TestSuite.run(TestSuite.java:238)
at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:83)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.ClassNotFoundException: pl.polidea.gradle.plugins.ProjectConfigurationPlugin not found.
at org.gradle.util.MultiParentClassLoader.loadClass(MultiParentClassLoader.java:51)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at org.gradle.api.internal.plugins.DefaultPluginRegistry.getTypeForId(DefaultPluginRegistry.java:100)
... 42 more

Answer 1

As in comment. I used the classes directly and it worked like that:
project.project.plugins.apply(SomePlugin.class)
project.project.plugins.apply(SomeOtherPlugin.class)