diff --git a/tests/test_idle.py b/tests/test_idle.py
index b2eee726574eb484ddaadcff90fadc17e7fadb05..84a11b968882cac97ecfec08fcc19406dc2cdf0c 100644
--- a/tests/test_idle.py
+++ b/tests/test_idle.py
@@ -178,7 +178,7 @@ def _test_block():
     # Be relaxed about precision - timing
     # can sometimes be pretty sloppy when
     # running in a docker container.
-    assert abs((end - start) < 2) < 0.05
+    assert abs((end - start) - 2) < 0.05
 
     if fslplatform.haveGui:
         assert called[0]