[Issue 108] Add testing unique article title on creating new article

Resolves #108

Scope of changes:

I added two tests for creating new articles (POST method) with enabled validation of title uniqueness
I created a new helper file for enabling/disabling feature flags (feature-file.helper.ts)
I changed the instances of enabling/disabling feature flags in older tests to the new helper
I added a new article title generator in the test-data folder
I introduced faker in the project and used it in the unique article generator function
In the new tests, I proposed a new way of building JSON for the data key in the request function

How to use it:

New helper `feature-file.helper.ts`

I propose using the new helper function in hook beforeAll and disabling it in hook afterAll. To use the function, pass the request parameter as the context, the name of the flag (to be checked in GAD documentation) and boolean isEnabled (true if you want to enable the flag and false to disable it), e.g.

await enableFeatureFlag(request, 'feature_validate_article_title', true);

Article title generator

At the moment you can:

generate unique article title using the faker book library; the function checks if the generated title is not present in the GAD database
get the title of the first article in the GAD database To use the function, you have to pass request parameter as the context

Faker

First install the faker library:

npm i @faker-js/faker

To use the faker, import it (I suggest importing only EN version to improve test performance):

import {faker } from '@faker-js/faker/locale/en'

Any other comments?

In the generateUniqueArticleTitle function, I used the while loop with if condition. Remarks:

ESLint detects the IF loops and displays warnings, but I think in this case it is justified to use IF, so I skipped ESLint checks for one line
There is a minimal probability that the faker will generate titles already present in the GAD database. To avoid this, I use the while loop, but I didn't enter any measures to stop the loop e.g. after 50 unsuccessful iterations (I think the chances are to small to make such fuses)
Occasionally some tests are flaky (e.g. Returns 422 status code when updating the article with the title equal to another article title with enabled flag in article-id-put.spec.ts) when all the tests are fired at once. At the moment I haven't discovered the problem

Before submitting Pull Request, I've ensured that:

[x] The PR is associated with the relevant Issue before its creation.
[x] All new and existing tests passed
[x] My commit messages follow the kawqa-gad-playwright project's git commit message format.

kat-kan / kawqa-gad-playwright