Add testsuite for unit- and integration tests

[gribok]

Based on #64, I created a basic test suite with following features:

• Unit-Testing of all help function, like date.is_date
• Integration-Testing of API endpoints (validation agains output from tests/expected_output)
• Add example data to tests/example_data for testing
• Mocking of app.data.requests.get and app.data.datetime to enforce data fetch locally from tests/example_data
• Edit of README.md for testing and linting
• Add pytest and pytest to Pipfile to dev-packages
• Randomize testing possible to test for stable code
• Update Pipfile.lock with new dev-dependencies

Testing of PR:

$ pytest -s -v tests/

ToDos:

• Add additonal testcases for endpoint /all. It is hard to test due to caching mechanism. Need to check, if it is possible to deactivate caching during testing
• Optional: Contol testing per Makefile
• Optional: Add to CI-pipeline

[ExpDev07]

This is gonna conflict with /v2/: https://github.com/ExpDev07/coronavirus-tracker-api/tree/v2 😢

[gribok]

No problem. I will waiting for release of v2 and adapt the testcases

[ExpDev07]

@gribok Really appreciate it.

[ExpDev07]

You should be good to make your edits now :). /v2/ is released.

[ExpDev07]

Is it necessary to have testing for legacy endpoints? Shouldn't we rather focus on maintaining testing for the new /v2/ endpoints??

[ExpDev07]

The data module no longer exists.

[gribok]

Already obsolet. Accidentally push commits to early. :-)

[ExpDev07]

Conflicts needed to be resolved.

[gribok]

Fixed all merge conflicts.
Adapt testsuite to v2.

Check it out. :-)

Some points to highlights;

• Due to cache mechanism, it is important to mock same datetime for latest key
  • Create constant variable test_jhu.DATETIME_STRING
• Return data of API endpoints validate against expected output for /v1 and /v2 endpoints

Would be nice, to be added to contrib-list

[ExpDev07]

Looks good sir.

[ExpDev07]

@all-contributors please add @gribok for code and testing.

[allcontributors]

@ExpDev07

I've put up a pull request to add @gribok! 🎉