diff --git a/Test/Tester.hs b/Test/Tester.hs
index 35cf58d..31f5166 100644
--- a/Test/Tester.hs
+++ b/Test/Tester.hs
@@ -4,7 +4,8 @@ module Test.Tester where
 import Data.Encoding
 import Test.HUnit
 import Data.Word
-import Data.ByteString (pack)
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy as LBS
 import Control.Exception (catchDyn,evaluate)
 
 data EncodingTest
@@ -12,26 +13,56 @@ data EncodingTest
 		EncodingTest enc String [Word8]
 	| forall enc. (Encoding enc,Show enc) =>
 		DecodingError enc [Word8] DecodingException
+	| forall enc. (Encoding enc,Show enc) =>
+		EncodingError enc String EncodingException
 
 instance Testable EncodingTest where
 	test (EncodingTest enc src trg) = TestList
 		[TestLabel (show enc ++ " encodable")
 			(TestCase $ (all (encodable enc) src) @=? True)
-		,TestLabel (show enc ++ " encoding")
+		,TestLabel (show enc ++ " encoding (strict)")
 			(TestCase $ (encode enc src) @=? bstr)
+		,TestLabel (show enc ++ " encoding (lazy)")
+			(TestCase $ (encodeLazy enc src) @=? lbstr)
 		,TestLabel (show enc ++ " decodable")
 			(TestCase $ (decodable enc bstr) @=? True)
-		,TestLabel (show enc ++ " decoding")
+		,TestLabel (show enc ++ " decoding (strict)")
 			(TestCase $ (decode enc bstr) @=? src)
+		,TestLabel (show enc ++ " decoding (lazy)")
+			(TestCase $ (decodeLazy enc lbstr) @=? src)
 		]
 		where
-		bstr = pack trg
+		bstr = BS.pack trg
+		lbstr = LBS.pack trg
 	test (DecodingError enc trg what) = TestList
-		[TestLabel (show enc ++ " not decodable") $
-			TestCase $ assert $ not $ decodable enc (pack trg)
-		,TestLabel (show enc ++ " decoding error") $ TestCase $ 
+		[TestLabel (show what++" not decodable in "++show enc) $
+			TestCase $ assert $ not $ decodable enc (BS.pack trg)
+		,TestLabel (show enc ++ " decoding error (strict)") $ TestCase $ 
 			catchDyn (do
-				evaluate (decode enc (pack trg) == "")
-				return ())
+				mapM_ evaluate (decode enc (BS.pack trg))
+				assertFailure "No exception thrown"
+				)
+				(\exc -> exc @=? what)
+		,TestLabel (show enc ++ " decoding error (lazy)") $ TestCase $ 
+			catchDyn (do
+				mapM_ evaluate (decodeLazy enc (LBS.pack trg))
+				assertFailure "No exception thrown"
+				)
+				(\exc -> exc @=? what)
+		]
+	test (EncodingError enc src what) = TestList
+		[TestLabel (show src ++ " not encodable in " ++ show enc) $
+			TestCase $ assert $ not $ all (encodable enc) src
+		,TestLabel (show enc ++ " encoding error (strict)") $ TestCase $
+			catchDyn (do
+				evaluate (encode enc src)
+				assertFailure "No exception thrown"
+				)
+				(\exc -> exc @=? what)
+		,TestLabel (show enc ++ " encoding error (lazy)") $ TestCase $
+			catchDyn (do
+				evaluate (encodeLazy enc src)
+				assertFailure "No exception thrown"
+				)
 				(\exc -> exc @=? what)
 		]