Fixed missing dependency to pytest

[Tom-Kingstone]

NOTE: Depends on BHoM/Python_Toolkit#181

Issues addressed by this PR

Closes #312

Test files

run run_tests.bat after fresh install

Changelog

Additional comments

[Tom-Kingstone]

@BHoMBot check required

[bhombot-ci]

@Tom-Kingstone to confirm, the following actions are now queued:

• check code-compliance
• check documentation-compliance
• check project-compliance
• check core
• check null-handling
• check serialisation
• check versioning
• check installer

There are 9 requests in the queue ahead of you.

[Tom-Kingstone]

@BHoMBot check copyright-compliance
@BHoMBot check dataset-compliance

[bhombot-ci]

@Tom-Kingstone to confirm, the following actions are now queued:

• check copyright-compliance
• check dataset-compliance

There are 9 requests in the queue ahead of you.

[bhombot-ci]

@Tom-Kingstone just to let you know, I have provided a check-installer result to this Pull Request as it was detected to be linked to other Pull Requests in a series. The comment which triggered this check came from @Tom-Kingstone on Python_Toolkit

[bhombot-ci]

The check installer has already been run previously and recorded as a successful check. This check has not been run again at this time.

[Dmamedova]

successful installation as well as all tests passing!

[Tom-Kingstone]

@BHoMBot check unit-tests
@BHoMBot check ready-to-merge

[bhombot-ci]

@Tom-Kingstone to confirm, the following actions are now queued:

• check unit-tests
• check ready-to-merge