public void HasCount_WithEmptyEnumerableAndEmptyCount_ExpectsTrue()
 => True(ENMRBL_EMPTY.HasCount(0));
 public void HasCount_WithEmptyEnumerableAndPositiveCount_ExpectsFalse()
 => False(ENMRBL_EMPTY.HasCount(COUNT_ANY));
 public void HasCount_WithEmptyEnumerableAndNegativeCount_Throws()
 => Throws <ArgumentOutOfRangeException>(
     () => ENMRBL_EMPTY.HasCount(-COUNT_ANY));