diff --git a/CHANGES b/CHANGES
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,8 @@
-## [0.2.0.17](https://github.com/diagrams/active/tree/v0.2.0.16) (2023-03-31)
+## [0.2.0.18](https://github.com/diagrams/active/tree/v0.2.0.18) (2023-06-10)
+
+- Fix failing test case ([#43](https://github.com/diagrams/active/issues/43))
+
+## [0.2.0.17](https://github.com/diagrams/active/tree/v0.2.0.17) (2023-03-31)
 
 - Updates for GHC 9.6
 - Allow `base-4.18`, `semigroupoids-6.0`
diff --git a/active.cabal b/active.cabal
--- a/active.cabal
+++ b/active.cabal
@@ -1,6 +1,6 @@
 cabal-version:       1.18
 name:                active
-version:             0.2.0.17
+version:             0.2.0.18
 synopsis:            Abstractions for animation
 description:         "Active" abstraction for animated things with finite start and end times.
 license:             BSD3
diff --git a/test/active-tests.hs b/test/active-tests.hs
--- a/test/active-tests.hs
+++ b/test/active-tests.hs
@@ -133,8 +133,9 @@
  where a1 = fromDynamic d1
        a2 = fromDynamic d2
 
-prop_during_end :: Dynamic Bool -> Dynamic Bool -> Bool
+prop_during_end :: Dynamic Bool -> Dynamic Bool -> Property
 prop_during_end d1 d2 =
+  ((duration <$> activeEra a2) > Just 0) && ((duration <$> activeEra a1) > Just 0) ==>
   (end <$> activeEra (a1 `during` a2)) == (end <$> activeEra a2)
  where a1 = fromDynamic d1
        a2 = fromDynamic d2