diff --git a/trace-foreign-calls/test/Main.hs b/trace-foreign-calls/test/Main.hs
index 0dc059d..ffd8761 100644
--- a/trace-foreign-calls/test/Main.hs
+++ b/trace-foreign-calls/test/Main.hs
@@ -1,34 +1,17 @@
 module Main (main) where
 
 import Control.Concurrent.Async (concurrently)
-import Test.Tasty
-import Test.Tasty.HUnit
-import Test.Tasty.Runners (NumThreads(..))
 
 import Test.TraceForeignCalls.UsePlugin
 
 main :: IO ()
-main = defaultMain $ localOption (NumThreads 1) $
-    testGroup "trace-foreign-calls" [
-        testCase "answerIO" $ do
-          answer <- answerIO
-          assertEqual "" 42 $ answer
-      , testCase "answerPure" $ do
-          let answer = answerPure
-          assertEqual "" 42 $ answer
-      , testCase "slowAddIO" $ do
-          let a = 1_000_000_000
-              b = 2_000_000_000
-          result <- slowAddIO a b
-          assertEqual "" (a + b) $ result
-      , testCase "slowAddPure" $ do
-          let a = 1_000_000_000
-              b = 2_000_000_000
-          let result = slowAddPure a b
-          assertEqual "" (a + b) $ result
-      , testCase "slowAddConcurrent" $ do
-          let a = 1_000_000_000
-              b = 2_000_000_000
-          (ab, ba) <- concurrently (slowAddIO a b) (slowAddIO b a)
-          assertEqual "" ab ba
-      ]
+main = do
+    print =<< answerIO
+    print $ answerPure
+    print =<< slowAddIO a b
+    print $ slowAddPure a b
+    (ab, ba) <- concurrently (slowAddIO a b) (slowAddIO b a)
+    print (ab, ba)
+  where
+    a = 1_000_000_000
+    b = 2_000_000_000
diff --git a/trace-foreign-calls/test/Test/TraceForeignCalls/UsePlugin.hs b/trace-foreign-calls/test/Test/TraceForeignCalls/UsePlugin.hs
index 50b956f..f351383 100644
--- a/trace-foreign-calls/test/Test/TraceForeignCalls/UsePlugin.hs
+++ b/trace-foreign-calls/test/Test/TraceForeignCalls/UsePlugin.hs
@@ -13,11 +13,11 @@ module Test.TraceForeignCalls.UsePlugin (
 
 import Foreign.C
 
-foreign import capi "test_cbits.h answer"   c_answerIO   :: IO CInt
-foreign import capi "test_cbits.h answer"   c_answerPure ::    CInt
+foreign import capi unsafe "test_cbits.h answer"   c_answerIO   :: IO CInt
+foreign import capi unsafe "test_cbits.h answer"   c_answerPure ::    CInt
 
-foreign import capi "test_cbits.h slow_add" c_slowAddIO   :: CLong -> CLong -> IO CLong
-foreign import capi "test_cbits.h slow_add" c_slowAddPure :: CLong -> CLong ->    CLong
+foreign import capi unsafe "test_cbits.h slow_add" c_slowAddIO   :: CLong -> CLong -> IO CLong
+foreign import capi unsafe "test_cbits.h slow_add" c_slowAddPure :: CLong -> CLong ->    CLong
 
 answerIO :: IO Int
 answerIO = fromIntegral <$> c_answerIO
diff --git a/trace-foreign-calls/trace-foreign-calls.cabal b/trace-foreign-calls/trace-foreign-calls.cabal
index 2f8a4a9..5caf117 100644
--- a/trace-foreign-calls/trace-foreign-calls.cabal
+++ b/trace-foreign-calls/trace-foreign-calls.cabal
@@ -62,7 +62,7 @@ test-suite test-trace-foreign-calls
       exitcode-stdio-1.0
   ghc-options:
       -threaded
-      "-with-rtsopts -l -N"
+      "-with-rtsopts -l -N2"
   cc-options:
       -O0
   hs-source-dirs:
@@ -81,7 +81,5 @@ test-suite test-trace-foreign-calls
   build-depends:
       -- external dependencies
     , async
-    , tasty
-    , tasty-hunit