No change in production logic.
This adds missing tests to improve test coverage. This does not change
ShellJS behavior at all--all test cases are testing already-working
functionality.
One test case has been renamed for clarity.
For the "omit directory if missing recursive flag" case, we were
actually already testing that in another case, but we were testing
multiple things in that test case. It's better to test this one error
condition explicitly in its own case.
When adding real tests for `parseOptions()`, we need to explicitly clear
`common.state.error` because we're testing an internal function, not a
wrapped command.
Partial fix for #671
35016ce1e7