add more rule_registry unit tests

[mgiota]

Fixes #120322

[mgiota]

@weltenwort Before I open this PR for review, I would like your input regarding what's the recommended way to mock a class constructor. Later in my test I do

expect(
        jest.requireMock('../rule_data_client/rule_data_client').RuleDataClient
      ).toHaveBeenCalled();

and it works. I am just wondering if there's a better way.

[weltenwort]

Looks like there already is a mock implementation of the rule data client in

kibana/x-pack/plugins/rule_registry/server/rule_data_client/rule_data_client.mock.ts

Lines 21 to 43 in bfa8b3c

	export const createRuleDataClientMock = (
	indexName: string = '.alerts-security.alerts'
	): RuleDataClientMock => {
	const bulk = jest.fn();
	const search = jest.fn();
	const getDynamicIndexPattern = jest.fn();
	return {
	indexName,
	kibanaVersion: '7.16.0',
	isWriteEnabled: jest.fn(() => true),
	// @ts-ignore 4.3.5 upgrade
	getReader: jest.fn((_options?: { namespace?: string }) => ({
	search,
	getDynamicIndexPattern,
	})),
	getWriter: jest.fn(() => ({
	bulk,
	})),
	};
	};

. So maybe you could use that like this:

jest.mock('../rule_data_client/rule_data_client', () => ({
  RuleDataClient: jest.fn().mockImplementation(createRuleDataClientMock),
}));

And further down I saw you're calling jest.mock again. Instead I would recommend to just import the RuleDataClient normally. The jest mocking mechanism will make sure it's replaced with the mock.

Similarly, it looks like you're calling jest.mock('./resource_installer', () => { inside of a test case. I think it's safer to only call jest.mock on the top level of the file as it needs to be evaluated before any import.

[mgiota]

@elasticmachine merge upstream

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: fcf257f
• Storybooks Preview

Metrics [docs]

✅ unchanged

History

• 💚 Build #11035 succeeded 9b136d0
• 💔 Build #10927 failed 84a6eac
• 💔 Build #10873 failed 895d992

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

cc @mgiota

[ersin-erdal]

Usually this means we don't use any dependency injection model :)
Apart from this, the tests look good :)

[mgiota]

@ersin-erdal Exactly. I had troubles mocking constructors like RuleDataClient or ResourceInstaller in the rule_data_plugin_service.test. I was thinking to refactor using dependency injection instead of directly importing the dependencies. Let's discuss about this during our today's meeting

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	8.0

This backport PR will be merged automatically after passing CI.