gradle test raise error: java.lang.NoClassDefFoundError: Could not initialize class groovy.lang.GroovySystem

I try to run "gradle test", and get error

My test is

class HelperTest extends ro.gd.Test {
    Plugin o;

    void setUp() {
        o = new Plugin();
    }

    void testGetIdeaDeps() {
        def r = o.ideaDeps
        asrHaveVal r
    }
}

when i run gradle test, it raise:

junit.framework.AssertionFailedError: Exception in constructor: testGetIdeaDeps (java.lang.NoClassDefFoundError: Could not initialize class groovy.lang.GroovySystem
    at org.codehaus.groovy.reflection.ClassInfo.isValidWeakMetaClass(ClassInfo.java:221)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClassForClass(ClassInfo.java:191)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClass(ClassInfo.java:236)
    at ro.gd.idea.HelperTest.$getStaticMetaClass(HelperTest.groovy)
    at ro.Test.<init>(Test.groovy)
    at ro.gd.Test.<init>(Test.groovy)
    at ro.gd.idea.HelperTest.<init>(HelperTest.groovy)
...

Here is my full code