Essentially, a double majority standard applies a two-part test to a vote outcome before a measure is passed:

The Court gave a two-part test to determine whether a proceeding deals with a criminal matter.

The Court relied on a two-part test for ancillary authority, laid out in Am.

We're going to do a two-part test, Rachel.

The Court developed a two-part test to determine whether the plaintiffs had standing to sue.

The decision puts local governments to a two-part test.

As to the requirement of fairness, the court laid out a two-part test:

But their performance on the verbal part of the two-part test improved more slowly, remaining far below what it was two decades ago.

Midcal's two-part test for whether to treat an action as a "state action"

Over the last two decades, the Supreme Court has established a two-part test for capital crimes.