GetMostRecentContiguousMonths finds the start time of the most recent set of continuous months.

IsCurrentDay checks if :t: is in the current day, as defined by :compare: generally, pass in time.Now().UTC() as :compare:.

IsCurrentMonth checks if :t: is in the current month, as defined by :compare: generally, pass in time.Now().UTC() as :compare:.

IsMonthStart checks if :t: is the start of the month.

IsPreviousMonth checks if :t: is in the month directly before :toCompare:.

Compute the N-month period before the given date.

NormalizeToYear returns date normalized to the latest date within one year of normal.

ParseTimeFromPath returns a UTC time from a path of the form '<timestamp>/', where <timestamp> is a Unix timestamp.

Skip this test if too close to the end of a month!.

This interface allows unit tests to substitute in a simulated Clock.