diff --git a/tests/pyb/extint.py b/tests/pyb/extint.py
index 47d84c8b5e46ba0e5b348f4c35831dd103472877..a8ba484b1c6849d6e42838d203fb45435e4744a8 100644
--- a/tests/pyb/extint.py
+++ b/tests/pyb/extint.py
@@ -1,8 +1,17 @@
 import pyb
 
+# test basic functionality
 ext = pyb.ExtInt('X1', pyb.ExtInt.IRQ_RISING, pyb.Pin.PULL_DOWN, lambda l:print('line:', l))
 ext.disable()
 ext.enable()
 print(ext.line())
 ext.swint()
+
+# test swint while disabled, then again after re-enabled
+ext.disable()
+ext.swint()
+ext.enable()
+ext.swint()
+
+# disable now that the test is finished
 ext.disable()