diff --git a/Test/Tests.hs b/Test/Tests.hs
index d6ebe3a..52911bc 100644
--- a/Test/Tests.hs
+++ b/Test/Tests.hs
@@ -3,6 +3,7 @@ module Test.Tests where
 import Data.Encoding
 import Data.Encoding.ASCII
 import Data.Encoding.UTF8
+import Data.Encoding.UTF16
 import Test.Tester
 import Test.HUnit
 
@@ -27,6 +28,8 @@ utf8Tests = TestList $ map test $
 		[0xE6,0x97,0xA5,0xE6,0x9C,0xAC,0xE8,0xAA,0x9E]
 	,EncodingTest enc "\x233B4"
 		[0xF0,0xA3,0x8E,0xB4]
+	,EncodingTest enc ""
+		[]
 	-- First possible sequence of a certain length
 	,EncodingTest enc "\x0000"
 		[0x00]
@@ -49,7 +52,21 @@ utf8Tests = TestList $ map test $
 	,EncodingTest enc "\xE000"
 		[0xEE,0x80,0x80]
 	,EncodingTest enc "\xFFFD"
-		[0xEF,0xBF,0xBD]]
+		[0xEF,0xBF,0xBD]
+	-- Illegal starting characters
+	,DecodingError enc
+		[0x65,0x55,0x85]
+		(IllegalCharacter 0x85)
+	-- Unexpected end
+	,DecodingError enc
+		[0x41,0xE2,0x89,0xA2,0xCE]
+		UnexpectedEnd
+	,DecodingError enc
+		[0x41,0xE2,0x89]
+		UnexpectedEnd
+	,DecodingError enc
+		[0x41,0xE2]
+		UnexpectedEnd]
 	| enc <- [UTF8,UTF8Strict]
 	]++
 	[DecodingError UTF8 [0xFE] (IllegalCharacter 0xFE)
@@ -75,4 +92,45 @@ utf8Tests = TestList $ map test $
 		(IllegalRepresentation [0xE0,0x80,0x80])
 	,DecodingError UTF8Strict [0xF0,0x80,0x80,0x80]
 		(IllegalRepresentation [0xF0,0x80,0x80,0x80])
+	-- Invalid extends
+	-- 2 of 2
+	,DecodingError UTF8Strict [0xCC,0x1C,0xE0]
+		(IllegalCharacter 0x1C)
+	-- 2 of 3
+	,DecodingError UTF8Strict [0xE3,0x6C,0xB3]
+		(IllegalCharacter 0x6C)
+	-- 3 of 3
+	,DecodingError UTF8Strict [0xE3,0xB4,0x6D]
+		(IllegalCharacter 0x6D)
+	-- 2 of 4
+	,DecodingError UTF8Strict [0xF2,0x6C,0xB3,0xB3]
+		(IllegalCharacter 0x6C)
+	-- 3 of 4
+	,DecodingError UTF8Strict [0xF2,0xB3,0x6C,0xB3]
+		(IllegalCharacter 0x6C)
+	-- 4 of 4
+	,DecodingError UTF8Strict [0xF2,0xB3,0xB3,0x6C]
+		(IllegalCharacter 0x6C)
+	]
+
+utf16Tests :: Test
+utf16Tests = TestList $ map test $
+	[EncodingTest UTF16BE "z"
+		[0x00,0x7A]
+	,EncodingTest UTF16BE "\x6C34"
+		[0x6C,0x34]
+	,EncodingTest UTF16BE "\x1D11E"
+		[0xD8,0x34,0xDD,0x1E]
+	,EncodingTest UTF16 "\x6C34z\x1D11E"
+		[0xFE,0xFF,0x6C,0x34,0x00,0x7A,0xD8,0x34,0xDD,0x1E]
+	,EncodingTest UTF16BE "˨"
+		[0x02,0xE8]
+	,DecodingError UTF16LE [0x65,0xDC]
+		(IllegalCharacter 0xDC)
+	,DecodingError UTF16BE [0xDC]
+		(IllegalCharacter 0xDC)
+	,DecodingError UTF16BE [0xD9,0x78,0xDA]
+		(IllegalCharacter 0xDA)
+	,DecodingError UTF16BE [0xD9,0x78,0xDA,0x66]
+		(IllegalCharacter 0xDA)
 	]