to be the start of
Passes if the moment instance represents the start of a unit of time.
expect(moment('2015-01-01'), 'to be the start of year');
It supports start-of-time units that are supported by moment#startOf.
When the assertion fails you'll get this output:
expect(moment('2015-01-01 01'), 'to be the start of year');
expected moment('2015-01-01T01:00:00.000+01:00') to be the start of year
moment(
'2015-01-01T01:00:00.000+01:00'
//
//
//
should be '2015-01-01T00:00:00.000+01:00'
2015-01-01T01:00:00.000+01:00
2015-01-01T00:00:00.000+01:00
)