to use the validator to run your own tests?

It is possible to run your own tests when the validator checks your plug-in.

First you have to register a test factory in your plugin factory:

#include "public.sdk/source/vst/utility/testing.h"
 
BEGIN_FACTORY_DEF(...
 
DEF_CLASS2 (Your Plugin Processor)
DEF_CLASS2 (Your Plugin Controller)
 
DEF_CLASS2 (INLINE_UID_FROM_FUID (getTestFactoryUID ()), PClassInfo::kManyInstances, kTestClass,
           "Test Factory", 0, "", "", "", createTestFactoryInstance)
 
END_FACTORY

Second: write your tests:

#include "public.sdk/source/main/moduleinit.h"
#include "public.sdk/source/vst/utility/testing.h"
 
static ModuleInitializer InitMyTests ([] () {
    registerTest ("MyTests", STR ("two plus two is four"), [] (ITestResult* testResult) {
        auto result = 2 + 2;
        if (result == 4)
            return true;
        testResult->addErrorMessage (STR ("Unexpected universe change where 2+2 != 4."));
        return false;
    });
});

If you need access to your audio effect or edit controller you can write your tests as done in the adelay example:

#include "public.sdk/source/main/moduleinit.h"
#include "public.sdk/source/vst/testsuite/vsttestsuite.h"
#include "public.sdk/source/vst/utility/testing.h"
 
static ModuleInitializer InitMyTests ([] () {
    registerTest ("MyTests", STR ("check one two three"), [] (FUnknown* context, ITestResult*
                                                              testResult)
    {
        if (auto plugProvider = U::cast<ITestPlugProvider> (context))
        {
            auto controller = plugProvider->getController ();
            auto testController = U::cast<IDelayTestController> (controller);
            if (!controller)
            {
                testResult->addErrorMessage (String ("Unknown IEditController"));
                return false;
            }
            bool result = testController->doTest ();
            plugProvider->releasePlugIn (nullptr, controller);
 
            return (result);
        }
        return false;
    });
});

After that recompile and if the validator does not run automatically after every build, start the validator manually and let it check your plug-in.