content: tests = all (== True)
    [ isInteger (5          :: Integer)
    , isInteger (5.0        :: Decimal)
    , isInteger (-5         :: Integer)
    , isInteger (0          :: Decimal)
    , isInteger (-2.1e120   :: Double)
    , isInteger (5 % 1      :: Rational)
    , isInteger (4 % 2      :: Rational)
    , isInteger (5 :+ 0     :: Complex Integer)
    , isInteger (5.0 :+ 0.0 :: Complex Decimal)
    , isInteger (6 % 3 :+ 0 :: Complex Rational)
    , isInteger (1/0        :: Double) -- Infinity is integer
    , isInteger (1.1/0      :: Double) -- Infinity is integer
    , not $ isInteger (5.01       :: Decimal)
    , not $ isInteger (-5e-2      :: Double)
    , not $ isInteger (5 % 3      :: Rational)
    , not $ isInteger (5 :+ 1     :: Complex Integer)
    , not $ isInteger (6 % 4 :+ 0 :: Complex Rational)
    , not $ isInteger (5.0 :+ 1.0 :: Complex Decimal)
    , almostInteger 0.01 2.001
    , almostInteger 0.01 (-1.999999)
    , almostInteger (1 % 10) (24 % 23)
    , not $ almostInteger 0.01 2.02
    , almostIntegerC 0.001 (5.999999 :+ 0.000001)
    ]
  