diff --git a/TAP.idr b/TAP.idr
index 483fd9b..22ffd75 100644
--- a/TAP.idr
+++ b/TAP.idr
@@ -126,7 +126,7 @@ export
 skip : Test -> Test
 skip = skipWith ""
 
-||| test that an expression fails in an expected way.
+||| test that an action fails in an expected way.
 ||| - if the body returns `Left err` and the predicate given returns `True`,
 |||   then the test succeeds
 ||| - if the body returns `Left err` and the predicate given returns `False`,
@@ -134,13 +134,19 @@ skip = skipWith ""
 ||| - if the body returns `Right val`, then the test fails with
 |||   `{success: val}`
 export
-testThrows : (ToInfo e, Show a) =>
-             String -> (e -> Bool) -> Lazy (Either e a) -> Test
-testThrows label p act = One $ MakeTest label $ do
-  case !(lazyToIO act) of
+testThrowsIO : (ToInfo e, Show a) =>
+               String -> (e -> Bool) -> EitherT e IO a -> Test
+testThrowsIO label p act = One $ MakeTest label $ do
+  case !(runEitherT act) of
        Left  err => if p err then result True () else result False err
        Right val => result False [("success", val)]
 
+||| pure version of `testThrowsIO`
+export
+testThrows : (ToInfo e, Show a) =>
+           String -> (e -> Bool) -> Lazy (Either e a) -> Test
+testThrows label p act = testThrowsIO label p $ MkEitherT $ lazyToIO act
+
 infix 1 :-
 ||| make a test group
 export