Install the empty Guice module loader before the suite in openam-scripting and openam-audit-context tests #1187

Context

#1186 fixed a class-order dependence in the openam-core-rest tests. InjectorHolder builds its injector once per JVM, from the module loader InjectorConfiguration holds at that moment. A test class that reaches it before another class installs its loader therefore decides which injector every later class gets. The review of #1186 pointed at the same pattern in other modules, where tests install their loader in @BeforeClass or @BeforeMethod rather than before the suite.

Current state

Measured at 5eb929e, with the class order fixed by a TestNG suite XML (-Dsurefire.suiteXmlFiles). No order of a module's own test classes fails today, so the hazard is latent.

• openam-scripting. The default loader cannot build an injector on this test classpath: No implementation for NotificationBroker was bound, through CoreGuiceModule -> SessionGuiceModule. GroovyValidatorTest, JavaScriptValidatorTest and GroovyAstTransformEscapeTest install an empty loader in their @BeforeMethod setupGuiceModules() override. That happens before GuiceTestCase.setupGuiceModules() first reaches the holder, and none of the other 23 classes touches it.
  • A new class could reach InjectorHolder without a hook, for example through SupportedScriptingLanguage.getScriptValidator(), ScriptEngineConfigurator.updateConfig or ScriptingSetupListener. If it runs first, all three classes fail in setupGuiceModules with NoClassDefFoundError: Could not initialize class org.forgerock.guice.core.InjectorHolder.
  • Reproduced with a scratch class of that kind.
• openam-audit/openam-audit-context. AuditContextFilterTest is the only test class, and it installs its loader in @BeforeClass. Here the default loader builds an empty injector.
  • A new unhooked class that runs first leaves AuditContextFilterTest with that injector, and both of its tests fail with No implementation for TransactionIdConfiguration was bound.
  • Reproduced with a scratch class.
• openam-datastore. Nothing to do. No test reaches InjectorHolder, so nothing reads the loader IdRepoTestBase installs in @BeforeClass.

Proposed change

Test code only. In openam-scripting and openam-audit-context, install the empty loader from @BeforeSuite(alwaysRun = true), as IdentityResourceNotificationTest does in openam-core-rest after #1186.

In openam-scripting, one such hook in GroovyValidatorTest was enough to make the scratch-class order above pass. Once the holder has been built, GuiceTestCase registers a fresh injector for every test method.

The limits that apply in openam-core-rest apply here too:

• The hook covers the other classes only while surefire runs the module as one TestNG suite in one JVM, that is with the inherited forkCount=1 and reuseForks=true.
• TestNG creates an instance of every test class before it runs any @BeforeSuite method. A constructor or initializer that reaches InjectorHolder still comes first.