To run all tests simply run `swift test`, this will run both the unit- and integration-tests. To run them separately use the `--filter` flag, e.g. `swift test --filter IntegrationTests`
To enable test coverage display go "Scheme > Manage Schemes..." menu item and edit the "viz-swift-lib" scheme, select the Test configuration and under the Options tab enable "Gather coverage for some targets" and add the `viz-swift-lib` target.
After adding adding more unit tests the `swift test --generate-linuxmain` command has to be run and the XCTestManifest changes committed for the tests to be run on Linux.