yarn test: all tests passed but returned "error Command failed with exit code 1"

Question

I used to use npm but recently switched to yarn. When I run yarn test it shows all tests passed but below says error Command failed with exit code 1 with no other information on what could have caused this error

node version: 6.3.1

yarn version: 0.16.3

potential cause console.error node_modules/core-js/modules/es6.promise.js:117 Unhandled promise rejection Error: Actions may not be an undefined. at dispatch (/node_modules/redux-mock-store/lib/index.js:35:19) at /node_modules/redux-thunk/lib/index.js:14:16 at dispatch (/node_modules/redux/lib/applyMiddleware.js:45:18) at /src/actions/ontologies.js:159:7 at run (/node_modules/core-js/modules/es6.promise.js:87:22) at /node_modules/core-js/modules/es6.promise.js:100:28 at flush (/node_modules/core-js/modules/_microtask.js:18:9) at process._tickCallback (internal/process/next_tick.js:103:7)

Answer 1

In my case, it's caused by snapshots obsolete after some test code changes. So the solution is to delete those test data in the __snapshots__ folder

Answer 2

Answer:

the error code was due to line coverage being below the value that I defined (90%). It already told me line coverage 86.8% is below user defined value of 90% so I thought it unlikely that yarn would "double report" that error.