Exclude empty Dependency from tests

Author: fgaz

cabal-install/tests/UnitTests/Distribution/Client/ArbitraryInstances.hs

@@ -121,7 +121,7 @@ instance Arbitrary PackageName where
         packageChars  = filter isAlphaNum ['\0'..'\127']
 
 instance Arbitrary Dependency where
-    arbitrary = Dependency <$> arbitrary <*> arbitrary <*> arbitrary
+    arbitrary = Dependency <$> arbitrary <*> arbitrary <*> fmap getNonMEmpty arbitrary
 
 instance Arbitrary UnqualComponentName where
     -- same rules as package names