diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+0.3.5.2
+	* Remove unused ghc-prim dependency.
+	* Added unit tests for read and scientificP
+
 0.3.5.1
 	* Replace use of Vector from vector with Array from primitive.
 
diff --git a/scientific.cabal b/scientific.cabal
--- a/scientific.cabal
+++ b/scientific.cabal
@@ -1,5 +1,5 @@
 name:                scientific
-version:             0.3.5.1
+version:             0.3.5.2
 synopsis:            Numbers represented using scientific notation
 description:
   @Data.Scientific@ provides the number type 'Scientific'. Scientific numbers are
@@ -67,7 +67,6 @@
   other-extensions:    DeriveDataTypeable, BangPatterns
   ghc-options:         -Wall
   build-depends:       base        >= 4.3   && < 4.11
-                     , ghc-prim
                      , integer-logarithms >= 1 && <1.1
                      , deepseq     >= 1.3   && < 1.5
                      , text        >= 0.8   && < 1.3
diff --git a/test/test.hs b/test/test.hs
--- a/test/test.hs
+++ b/test/test.hs
@@ -34,6 +34,7 @@
 import qualified Data.ByteString.Lazy.Char8         as BLC8
 import qualified Data.ByteString.Builder.Scientific as B
 import qualified Data.ByteString.Builder            as B
+import           Text.ParserCombinators.ReadP (readP_to_S)
 
 main :: IO ()
 main = testMain $ testGroup "scientific"
@@ -55,6 +56,11 @@
     , testCase "reads \"(1.3 )\""  $ testReads "(1.3 )"  [(1.3, "")]
     , testCase "reads \"((1.3))\"" $ testReads "((1.3))" [(1.3, "")]
     , testCase "reads \" 1.3\""    $ testReads " 1.3"    [(1.3, "")]
+    , testCase "read \" ( ((  -1.0e+3 ) ))\"" $ testRead " ( ((  -1.0e+3 ) ))" (-1000.0)
+    , testCase "scientificP \"3\""       $ testScientificP "3"       [(3.0, "")]
+    , testCase "scientificP \"3.0e2\""   $ testScientificP "3.0e2"   [(3.0, "e2"), (300.0, "")]
+    , testCase "scientificP \"+3.0e+2\"" $ testScientificP "+3.0e+2" [(3.0, "e+2"), (300.0, "")]
+    , testCase "scientificP \"-3.0e-2\"" $ testScientificP "-3.0e-2" [(-3.0, "e-2"), (-3.0e-2, "")]
     ]
 
   , testGroup "Formatting"
@@ -217,6 +223,12 @@
 
 testReads :: String -> [(Scientific, String)] -> Assertion
 testReads inp out = reads inp @?= out
+
+testRead :: String -> Scientific -> Assertion
+testRead inp out = read inp @?= out
+
+testScientificP :: String -> [(Scientific, String)] -> Assertion
+testScientificP inp out = readP_to_S Scientific.scientificP inp @?= out
 
 genericIsFloating :: RealFrac a => a -> Bool
 genericIsFloating a = fromInteger (floor a :: Integer) /= a