public void Flatten_WithEmptyEnumerable_ExpectsSameEnumerable()
=> Utilities.AssertManySequencesEqual(
ENMRBL_EMPTY.Flatten(),
ENMRBL_EMPTY);
public void Flatten_WithEmptyEnumerableAndNullProvider_Throws()
=> Throws <ArgumentNullException>(
() => ENMRBL_EMPTY.Flatten(null).ToList());