diff --git a/fs-sim/CHANGELOG.md b/fs-sim/CHANGELOG.md
index 5fa04ad..ac82a3d 100644
--- a/fs-sim/CHANGELOG.md
+++ b/fs-sim/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Revision history for fs-sim
 
+## Next version -- ????-??-??
+
+### Breaking
+
+* Expose `openHandles` for testing.
+
 ## 0.3.0.1 -- 2024-10-02
 
 ### Patch
diff --git a/fs-sim/src/System/FS/Sim/MockFS.hs b/fs-sim/src/System/FS/Sim/MockFS.hs
index 8687d51..b8e4e53 100644
--- a/fs-sim/src/System/FS/Sim/MockFS.hs
+++ b/fs-sim/src/System/FS/Sim/MockFS.hs
@@ -46,6 +46,7 @@ module System.FS.Sim.MockFS (
   , renameFile
     -- * Exported for the benefit of tests only
   , Files
+  , openHandles
   , mockFiles
     -- ** opaque
   , ClosedHandleState