test/infamy: slight improvement to tap.py::Test.__exit__()

Before this change:

  ok 2 - Configure basic end-device firewall
  not ok 3 - Verify unused interface assigned to default zone
  # Exiting (2025-09-25 11:33:00)
  # Traceback (most recent call last):
  #   File "/home/jocke/src/x-misc/test/./case/infix_firewall/basic/test.py", line 127, in <module>
  #     assert unused_if not in public_zone["interface"], \
  #            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  # AssertionError: Unused interface e4 should be in default zone 'public', got interfaces: ['e2', 'e3', 'e5', 'e7', 'e8']

After this change:

  ok 2 - Configure basic end-device firewall
  not ok 3 - Verify unused interface assigned to default zone
  # Exiting (2025-09-25 11:35:00)
  #   File "/home/jocke/src/x-misc/test/./case/infix_firewall/basic/test.py", line 127, in <module>
  #     assert unused_if not in public_zone["interface"], \
  #            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  # Unused interface e4 should be in default zone 'public', got interfaces: ['e2', 'e3', 'e5', 'e7', 'e8']

Slightly shorter and arguably easier to read for a non-pythonic human.

Signed-off-by: Joachim Wiberg <[email protected]>

Author: troglobit

test/infamy/tap.py

@@ -30,7 +30,7 @@ def __enter__(self):
         self.out.flush()
         return self
 
-    def __exit__(self, _, e, __):
+    def __exit__(self, t, e, tb):
         now = datetime.datetime.now().strftime("%F %T")
         self.out.write(f"# Exiting ({now})\n")
         self.out.flush()
@@ -40,12 +40,16 @@ def __exit__(self, _, e, __):
         if not e:
             self._not_ok("Missing explicit test result\n")
         else:
-            if type(e) in (TestPass, TestSkip):
+            if t in (TestPass, TestSkip):
                 self.out.write(f"{self.steps}..{self.steps}\n")
                 self.out.flush()
                 raise SystemExit(0)
-
-            traceback.print_exception(e, file=self.commenter)
+            if t is AssertionError:
+                traceback.print_tb(tb, file=self.commenter)
+                self.out.write(f"{str(e)}\n")
+                self.out.flush()
+            else:
+                traceback.print_exception(e, file=self.commenter)
 
             if type(e) is subprocess.CalledProcessError:
                 print("Failing subprocess stdout:\n", e.stdout)