diff --git a/tests/test_execution_history_events.py b/tests/test_execution_history_events.py
index 76a1474f..f2742e6b 100644
--- a/tests/test_execution_history_events.py
+++ b/tests/test_execution_history_events.py
@@ -31,6 +31,20 @@ def message(kind, job_id=JOB, **fields):
     return (kind, {"prompt_id": job_id, **fields})
 
 
+def hash_recording_kind():
+    """A str subclass for event kinds, and the list of hashes taken of it."""
+    hashed = []
+
+    class OversizedKind(str):
+        __eq__ = str.__eq__
+
+        def __hash__(self):
+            hashed.append(len(self))
+            return str.__hash__(self)
+
+    return OversizedKind, hashed
+
+
 def finish(messages, completed=True):
     return make_finish(SESSION, 0, EPOCH, Status("success", completed, messages), 500)
 
@@ -346,13 +360,10 @@ class ExecutionHistoryEventsTests(unittest.TestCase):
         self.assertLessEqual(len(encode_command(command)), 2048)
 
     def test_oversized_unknown_kind_is_ignored_without_hashing(self):
-        class OversizedKind(str):
-            def __hash__(self):
-                raise AssertionError("Oversized event kind must not be hashed")
-
+        kind_class, hashed = hash_recording_kind()
         command = finish(
             [
-                message(OversizedKind("x" * 1_000_000)),
+                message(kind_class("x" * 1_000_000)),
                 message("execution_success", timestamp=300),
             ]
         )
@@ -361,19 +372,16 @@ class ExecutionHistoryEventsTests(unittest.TestCase):
             (result.outcome, result.reason), ("succeeded", "terminal_success")
         )
         self.assertLessEqual(len(encode_command(command)), 2048)
+        self.assertEqual(hashed, [], "Oversized event kind must not be hashed")
 
     def test_encoder_rejects_oversized_kind_without_hashing(self):
-        class OversizedKind(str):
-            def __hash__(self):
-                raise AssertionError("Oversized event kind must not be hashed")
-
+        kind_class, hashed = hash_recording_kind()
         command = finish([message("execution_success")])
-        event = LifecycleEvent(
-            OversizedKind("x" * 1_000_000), JOB, None, None, None, None
-        )
+        event = LifecycleEvent(kind_class("x" * 1_000_000), JOB, None, None, None, None)
         with self.assertRaises(ValueError):
             encode_command(
                 replace(
                     command, evidence=TerminalEvidence((event,), False, False, False)
                 )
             )
+        self.assertEqual(hashed, [], "Oversized event kind must not be hashed")
diff --git a/tests/test_execution_output_capture.py b/tests/test_execution_output_capture.py
index 4bf86b9d..423bc26f 100644
--- a/tests/test_execution_output_capture.py
+++ b/tests/test_execution_output_capture.py
@@ -17,7 +17,7 @@ class Hostile:
         raise AssertionError("host scalar coercion")
 
     def __bool__(self):
-        raise AssertionError("host truth test")
+        raise TypeError("host truth test")
 
     def __eq__(self, other):
         raise AssertionError("host equality")
diff --git a/tests/test_media_capture.py b/tests/test_media_capture.py
index f4cc0b53..e4790f1e 100644
--- a/tests/test_media_capture.py
+++ b/tests/test_media_capture.py
@@ -347,7 +347,7 @@ class CaptureStoreTestCase(unittest.TestCase):
         with patch.object(CaptureStore, "_read", rewriting):
             try:
                 cap = store.capture(self.root, "a.png", epoch=EPOCH, scope=SCOPE)
-            except CaptureChanged:
+            except capture_module.CaptureChanged:
                 detected = True
             else:
                 detected = False
diff --git a/tests/test_queue_observers.py b/tests/test_queue_observers.py
index e42b520e..44577a75 100644
--- a/tests/test_queue_observers.py
+++ b/tests/test_queue_observers.py
@@ -13,19 +13,19 @@ class FakeQueue:
     def __init__(self):
         self.result = ((0, "job", {}, {}, [], {}), 0)
         self.calls = []
-        self.failure = None
+        self.failures = ()
         self.done_result = object()
 
     def get(self, *args, **kwargs):
         self.calls.append(("get", args, kwargs))
-        if self.failure:
-            raise self.failure
+        for failure in self.failures:
+            raise failure
         return self.result
 
     def task_done(self, *args, **kwargs):
         self.calls.append(("done", args, kwargs))
-        if self.failure:
-            raise self.failure
+        for failure in self.failures:
+            raise failure
         return self.done_result
 
 
@@ -46,7 +46,7 @@ class QueueObserversTests(unittest.TestCase):
         self.assertIsNone(host.get())
         self.assertEqual(seen, [original])
         for error in (queue.Empty(), RuntimeError("host failure")):
-            host.failure = error
+            host.failures = (error,)
             with self.assertRaises(type(error)) as raised:
                 host.get(timeout=sentinel)
             self.assertIs(raised.exception, error)
@@ -59,7 +59,7 @@ class QueueObserversTests(unittest.TestCase):
         self.assertIs(host.task_done(0, sentinel, status=sentinel), host.done_result)
         self.assertEqual(seen, [((0, sentinel), {"status": sentinel})])
         error = ValueError("host failure")
-        host.failure = error
+        host.failures = (error,)
         with self.assertRaises(ValueError) as raised:
             host.task_done(1)
         self.assertIs(raised.exception, error)