diff --git a/hie.yaml b/hie.yaml
new file mode 100644
index 0000000..f0c7014
--- /dev/null
+++ b/hie.yaml
@@ -0,0 +1,2 @@
+cradle:
+  cabal:
\ No newline at end of file
diff --git a/tests/Approx.hs b/tests/Approx.hs
index c7dea2c..de3915f 100644
--- a/tests/Approx.hs
+++ b/tests/Approx.hs
@@ -10,10 +10,6 @@ approx0 n x = fromInteger (round $ x * (10^n)) / (10.0^^n)
 approx :: Int -> Complex Double -> Complex Double
 approx n z = approx0 n (realPart z) :+ approx0 n (imagPart z)
 
--- check whether rounded z1 and rounded z2 are equal
-approxEqual :: Int -> Complex Double -> Complex Double -> Bool
-approxEqual n z1 z2 = magnitude (approx n z1 - approx n z2) == 0.0
-
 assertApproxEqual :: String -> Int -> Complex Double -> Complex Double -> Assertion
 assertApproxEqual prefix n z1 z2 = 
   assertEqual prefix (approx n z1) (approx n z2)