@boehmalex thank you for the fix. Can you see if it's easy to add a test for this case in ExportImportTest?

@shawkins sorry for the late response. I tried to add a test when creating the fix, but with the usage of testRealmExportImport i couldn't manage to check for the expected exception, because the exception is converted to a standard UncaughtServerError in KeycloakErrorHandler.getResponse(...). And in this exception there is no cause/reason or something else left to get to the root cause.

But i did a little more testing and this could be a test (its actually working):

public void checkForRealmNotFoundExceptionWhenDirExportingNonExistentRealm() throws IOException {
        String realmName = "non-existent-realm";
        String targetDirPath = testingClient.testing().exportImport().getExportImportTestDirectory() + File.separator + "dirRealmExport";
        testingClient.testing().exportImport().setDir(targetDirPath);
        testingClient.testing().exportImport().setRealmName(realmName);
        Config.Scope config = new Config.SystemPropertiesScope("");

        DirExportProviderFactory dirExportProviderFactory = new DirExportProviderFactory();
        dirExportProviderFactory.init(config);

        KeycloakSessionFactory factory = KeycloakApplication.getSessionFactory();
        KeycloakSession keycloakSession = factory.create();
        ExportProvider exportProvider = dirExportProviderFactory.create(keycloakSession);

        try {
            exportProvider.exportModel();
        } catch (NullPointerException e) {
            assertEquals(String.format("realm not found by realm name '%s'", realmName), e.getMessage());
        }
    }

But i don't know if this is considered as an OK test, because its a little puzzled together and not using the testingClient.testing().exportImport().runExport();

The same test base could be used to test the Exception in SingleFileExportProvider.

Thank you for looking more into this @boehmalex

And in this exception there is no cause/reason or something else left to get to the root cause.

Right, you'd have to inspect the server log instead.

But i don't know if this is considered as an OK test, because its a little puzzled together and not using the testingClient.testing().exportImport().runExport();

I'm fine with this more direct style of test. It would be clearer though to just by-pass using testingClient.testing().exportImport() methods and instead use ExportImportConfig methods.

@shawkins Thanks for your input - valid point to use ExportImportConfig directly! I will update this PR and provide the tests at the end of next week at the earliest.