Added tests

[ZuluPro]

I added:

• A test project
• A test app
• A test for view
• A launcher at project root

[ZuluPro]

@fdemmer Any news ?

[fdemmer]

first of all, thank you for contributing, your time and effort is appreciated! :+1:

i am not sure about the pull-request as is though. i am a "purist" in the sense, that i think "less code is more". every line added potentially adds bugs and needs to be maintained. sometimes it is good to take a step back and ask, what do i want, what do i need to focus on and then only do that.

the pull-request adds a whole test project only to have one test actually run and that test mostly verifies that django and the test-project itself works. it does not verify any of the expected response headers (and you left a set_trace() in there).

so, i am going to reject the pull-request.

however, i also think tests are important. they must focus on testing what the library does though and should not cover aspects out of its control.

i am thinking tests should:

• not cover django as much as possible, keep "infrastructure" minimal (calling settings.configure() and django.setup() should be enough to have a "django instance" if neccessary; a django project can be super-small; having url routing to test a view function is already too much)
• not cover weasyprint functionality; actually generating pdf or images is out of scope of this library (mock the interface to weasyprint and verify the passed arguments)
• cover various attributes in WeasyTemplateResponseMixinand their effects
  • mostly response headers
  • the correct base_url is passed to weasyprint
  • the django_url_fetcher() returns correct paths to static and media files

thanks again for contributing!