Bring test suite up to date

test/data/ghc-mod-check/lib/Data/Foo.hs

@@ -0,0 +1,11 @@
+module Data.Foo where
+
+foo :: Int
+foo = undefined
+
+fibonacci :: Int -> Integer
+fibonacci n = fib 1 0 1
+  where
+    fib m x y
+      | n == m    = y
+      | otherwise = fib (m+1) y (x + y)