diff --git a/generation/src/CryptoNum.hs b/generation/src/CryptoNum.hs
index f7b2731..bee2492 100644
--- a/generation/src/CryptoNum.hs
+++ b/generation/src/CryptoNum.hs
@@ -24,7 +24,9 @@ declareCryptoNumInstance bitsize =
      out "#[cfg(test)]"
      out "use crate::testing::{build_test_path,run_test};"
      out "#[cfg(test)]"
-     out "use quickcheck::quickcheck;"
+     out "use quickcheck::{Arbitrary,Gen,quickcheck};"
+     out "#[cfg(test)]"
+     out "use std::fmt;"
      out ("use super::" ++ name ++ ";")
      blank
      implFor "CryptoNum" name $
@@ -96,13 +98,43 @@ declareCryptoNumInstance bitsize =
                     out ("idx -= 1;")
                out ("bytes[idx] = byte" ++ show (bytes-1) ++ ";")
      blank
+     let bytes = bitsize `div` 8
+         struct = "Bytes" ++ show bytes
+     out "#[cfg(test)]"
+     out "#[derive(Clone)]"
+     wrapIndent ("struct " ++ struct) $
+       out ("value: [u8; " ++ show bytes ++ "]")
+     blank
+     out "#[cfg(test)]"
+     implFor "PartialEq" struct $
+       wrapIndent ("fn eq(&self, other: &Self) -> bool") $
+         out "self.value.iter().zip(other.value.iter()).all(|(a,b)| a == b)"
+     blank
+     out "#[cfg(test)]"
+     implFor "fmt::Debug" struct $
+       wrapIndent ("fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result") $
+         out "f.debug_list().entries(self.value.iter()).finish()"
+     blank
+     out "#[cfg(test)]"
+     implFor "Arbitrary" struct $
+       wrapIndent ("fn arbitrary<G: Gen>(g: &mut G) -> Self") $
+         do out ("let mut res = " ++ struct ++ "{ value: [0; " ++ show bytes ++ "] };")
+            out ("g.fill_bytes(&mut res.value);")
+            out ("res")
+     blank
      out "#[cfg(test)]"
      wrapIndent "quickcheck!" $
        do wrapIndent ("fn to_from_ident(x: " ++ name ++ ") -> bool") $
-            do out ("let mut buffer = [0; " ++ show (bitsize `div` 8) ++ "];")
+            do out ("let mut buffer = [0; " ++ show bytes ++ "];")
                out ("x.to_bytes(&mut buffer);");
                out ("let y = " ++ name ++ "::from_bytes(&buffer);")
                out ("x == y")
+          blank
+          wrapIndent ("fn from_to_ident(x: " ++ struct ++ ") -> bool") $
+            do out ("let val = " ++ name ++ "::from_bytes(&x.value);")
+               out ("let mut buffer = [0; " ++ show bytes ++ "];")
+               out ("val.to_bytes(&mut buffer);")
+               out ("buffer.iter().zip(x.value.iter()).all(|(a,b)| a == b)")
      blank
      out "#[cfg(test)]"
      out "#[allow(non_snake_case)]"