Run the integration tests only when needed

[lslezak]

Problem

• Running the integration tests in the CI always is quite expensive, usually they take 8-10 minutes
• There are many cases when running integration tests is not needed and it just wastes resources and you need to wait longer before merging a pull request

Some examples when the integration tests should be skipped (if only these components are updated):

• Updating the command line interface
• Updating a README file or any documentation files
• Updating an unit test
• Updating examples
• Updating *.spec or *.changes files

Note

We also run the CI after any commit to a branch. Which means it can also help in this scenario:

• You create a branch and commit a code fix there
• Later you find out that an unit test fails
• You fix the unit test in another commit

The integration tests will run for the first commit but not for the second. When you create a pull request from that branch both integration and unit tests will run.

Solution

• Use path matching and run the integration tests only when a file relevant for the integration tests is updated
• The path list is not set in stone, we will need to adapt it if some files a removed or new ones are added.

[coveralls]

coverage: 72.158%. remained the same when pulling f127e0d on integration_test_runs into 9c7a6ad on master.