Migrating examples to integration tests to be run by pytest

[mattkwiecien]

We currently have 9 examples we run after tests to check the code is working as expected. This code moves those examples into tests that can be run by pytest.

• Added a new tests/integration directory
• Placed tests that use subprocess.run to run the examples in this directory and marked them as integration tests
  • I prefixed set -e to ensure the test fails if any commands fail
  • I capture the stdout and print it to the terminal to mimic the previous behavior.
• Updated pytest to skip integration tests unless requested with the --integration flag.
• Updated ci.yml to run integration tests after unit tests, and appending the output to the coverage file.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (da20744) 95.4% compared to head (92ddc4f) 96.2%.

Additional details and impacted files

@@           Coverage Diff            @@
##           master    #371     +/-   ##
========================================
+ Coverage    95.4%   96.2%   +0.8%     
========================================
  Files          35      35             
  Lines        2569    2569             
========================================
+ Hits         2451    2472     +21     
+ Misses        118      97     -21     

see 3 files with indirect coverage changes