Tests are to live in as many subdirectories as necessary for organizational purposes. Tests are not supposed to live in the root /test directory or the /test/mocha or /test/spectron (doesn't exist yet) directories.
You can execute tests by running npm test. This will npm run test-mocha and (not added yet).npm run test-spectron
For components that do not require Electron, it is recommended to write Mocha tests instead as they are lighter.
For a Mocha test to be executed by npm test or npm run test-mocha, it must be located in a subdirectory of /test/mocha matching the glob pattern *.test.js.
You may see files with the glob pattern *.subtest.js. These files are not named *.test.js for the purpose of organizing them in a single Mocha describe(). A main loader *.test.js file will require the *.subtest.js files for execution. See how workspace tests implement this.
Currently, there are no Spectron tests, nor is there the framework necessary to execute Spectron tests. However, Spectron test support will be added eventually.