Update README.md with unit tests and integration tests (#139722)

x-pack/plugins/cloud_security_posture/README.md

@@ -4,6 +4,81 @@ Cloud Posture automates the identification and remediation of risks across cloud
 
 ---
 
+## Table of contents
+
+- [Development](#development)
+  - [Local checks before creating a PR](#local-checks-before-creating-a-pr)
+  - [Install pre-commit hooks (optional)](#install-pre-commit-hooks-optional)
+  - [Running unit tests](#running-unit-tests)
+  - [Running integration tests](#running-integration-tests)
+
+---
+
 ## Development
 
-See the [kibana contributing guide](https://github.com/elastic/kibana/blob/main/CONTRIBUTING.md) for instructions setting up your development environment.
+See the [kibana contributing guide](https://github.com/elastic/kibana/blob/main/CONTRIBUTING.md) for instructions
+setting up your development environment.
+
+### Local checks before creating a PR
+
+Kibana has a pretty long CI process.
+Therefore, we suggest running the following commands locally before creating a PR:
+
+1. Typescript check: `node_modules/.bin/tsc -b x-pack/plugins/cloud_security_posture/tsconfig.json --pretty`
+2. Linter check: `yarn lint:es x-pack/plugins/cloud_security_posture`
+3. Unit tests: `yarn jest --config x-pack/plugins/cloud_security_posture/jest.config.js`
+
+### Install pre-commit hooks (optional)
+
+We
+use [pre-commit](https://docs.elastic.dev/kibana-dev-docs/getting-started/setup-dev-env#install-pre-commit-hook-optional)
+to run linters and tests before each commit. To install the pre-commit hooks, run the following command from the root of
+the repository:
+
+```bash
+node scripts/register_git_hook
+```
+
+### Running unit tests
+
+Our [unit tests](https://docs.elastic.dev/kibana-dev-docs/tutorials/testing-plugins#unit-testing) are written
+using [jest](https://jestjs.io/) framework.
+
+As a convention, we use the `.test.ts` suffix for all our tests.
+
+You can run all cloud security posture tests with the following command:
+
+```bash
+yarn jest --config x-pack/plugins/cloud_security_posture/jest.config.js
+```
+
+To run a specific test, you can use the `--testNamePattern` flag:
+
+```bash
+yarn jest --config x-pack/plugins/cloud_security_posture/jest.config.js --testNamePattern=FilePattern -t MyTest
+```
+
+### Running integration tests
+
+The cloud security posture plugin has
+also [integration tests](https://docs.elastic.dev/kibana-dev-docs/tutorials/testing-plugins#integration-tests) that run
+against a real Elasticsearch and Kibana instances.
+We use these tests to verify that the plugin works as expected when running in a real environment.
+In order to run the integration tests, you need to have a running Elasticsearch and Kibana instances with the
+integration test configuration.
+
+You can run Kibana and Elastic with the integration test configuration by running the following command from the root of
+the Kibana repository:
+
+```bash
+node scripts/functional_tests_server.js --config x-pack/test/api_integration/config.ts
+```
+
+** You should wait until the server is ready to accept connections before running the integration tests.
+
+Then, in a separate terminal, you can run the integration test.
+In order to do so, run the following command:
+
+``` bash  
+node scripts/functional_test_runner.js --config x-pack/test/api_integration/config.ts --include=test_file_path
+```