Scripting: add test for loading configuration for gradle scripts

idea/idea-core/src/org/jetbrains/kotlin/idea/core/script/configuration/listener/ScriptChangesNotifier.kt

@@ -52,6 +52,10 @@ internal class ScriptChangesNotifier(
 
                 val listener = getListener(project, file) ?: return
 
+                if (ApplicationManager.getApplication().isUnitTestMode) {
+                    listener.documentChanged(file, updater)
+                }
+
                 scriptsQueue.cancelAllRequests()
                 scriptsQueue.addRequest(
                     { listener.documentChanged(file, updater) },

idea/idea-core/src/org/jetbrains/kotlin/idea/core/script/configuration/utils/TestingBackgroundExecutor.kt

@@ -53,4 +53,6 @@ class TestingBackgroundExecutor internal constructor(
 
         return copy.isNotEmpty()
     }
+
+    fun noBackgroundTasks(): Boolean = backgroundQueue.isEmpty()
 }