Created by: gaearon
Fixes #532 (closed).
By default project won’t have --watch.
We will always assume that react-scripts test launches the watcher.
However we offer an escape hatch. If process.env.CI is defined, we disable watching. This should satisfy most use cases, and people who really insist on not using a watcher can always CI=true npm test. However our intention is to keep improving the watcher and we will push for it to become the default workflow.