diff --git a/tests/backend/media_test_assets.py b/tests/backend/media_test_assets.py
index 17890d0..11ce655 100644
--- a/tests/backend/media_test_assets.py
+++ b/tests/backend/media_test_assets.py
@@ -7,9 +7,7 @@ from __future__ import annotations
 import gzip
 import json
 
-TINY_PNG = (
-    bytes([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]) + b"\x00" * 32
-)
+TINY_PNG = bytes([0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A]) + b"\x00" * 32
 
 TINY_GIF = b"GIF89a" + b"\x00" * 32
 
diff --git a/tests/backend/test_audio_codec.py b/tests/backend/test_audio_codec.py
index 91e6474..f7fa51a 100644
--- a/tests/backend/test_audio_codec.py
+++ b/tests/backend/test_audio_codec.py
@@ -38,7 +38,9 @@ def _build_wav_pcm16(
         wf.setframerate(samplerate)
         frames = bytearray()
         for i in range(n_samples):
-            sample = int(0.3 * 32767 * math.sin(2 * math.pi * frequency * (i / samplerate)))
+            sample = int(
+                0.3 * 32767 * math.sin(2 * math.pi * frequency * (i / samplerate))
+            )
             for _ in range(channels):
                 frames.extend(struct.pack("<h", sample))
         wf.writeframes(bytes(frames))
@@ -84,7 +86,8 @@ def test_encode_pcm_to_ogg_opus_writes_valid_container():
             assert f.read(4) == b"OggS"
         assert os.path.getsize(out) > 0
     finally:
-        os.unlink(out)
+        if os.path.exists(out):
+            os.unlink(out)
 
 
 def test_encode_pcm_to_ogg_opus_resamples_arbitrary_rate():
@@ -104,7 +107,8 @@ def test_encode_pcm_to_ogg_opus_resamples_arbitrary_rate():
         with open(out, "rb") as f:
             assert f.read(4) == b"OggS"
     finally:
-        os.unlink(out)
+        if os.path.exists(out):
+            os.unlink(out)
 
 
 def test_encode_audio_to_ogg_opus_decodes_and_reencodes(tmp_path):
@@ -190,14 +194,17 @@ def test_encode_pcm_to_ogg_opus_preserves_duration(duration_seconds):
         sr = 48000
         n = int(sr * duration_seconds)
         t = np.arange(n, dtype=np.float32) / sr
-        samples = (0.3 * np.sin(2 * math.pi * 440.0 * t)).astype(np.float32).reshape(-1, 1)
+        samples = (
+            (0.3 * np.sin(2 * math.pi * 440.0 * t)).astype(np.float32).reshape(-1, 1)
+        )
         audio_codec.encode_pcm_to_ogg_opus(samples, sr, 1, out)
         encoded = _ogg_opus_duration_seconds(out)
         assert abs(encoded - duration_seconds) < 0.001, (
             f"expected {duration_seconds}s, got {encoded}s"
         )
     finally:
-        os.unlink(out)
+        if os.path.exists(out):
+            os.unlink(out)
 
 
 def test_encode_pcm_to_ogg_opus_audio_profile_keeps_stereo():
@@ -223,4 +230,5 @@ def test_encode_pcm_to_ogg_opus_audio_profile_keeps_stereo():
         assert channels == 2
         assert _ogg_opus_duration_seconds(out) == pytest.approx(1.0, abs=0.001)
     finally:
-        os.unlink(out)
+        if os.path.exists(out):
+            os.unlink(out)
diff --git a/tests/backend/test_interface_discovery_ifac.py b/tests/backend/test_interface_discovery_ifac.py
index abedfdb..27b8fc7 100644
--- a/tests/backend/test_interface_discovery_ifac.py
+++ b/tests/backend/test_interface_discovery_ifac.py
@@ -61,10 +61,9 @@ async def find_route_handler(app_instance, path, method):
 
 
 def test_normalize_handles_non_list_input():
-    assert (
-        ReticulumMeshChat.normalize_discovered_ifac_fields({"foo": "bar"})
-        == {"foo": "bar"}
-    )
+    assert ReticulumMeshChat.normalize_discovered_ifac_fields({"foo": "bar"}) == {
+        "foo": "bar"
+    }
     assert ReticulumMeshChat.normalize_discovered_ifac_fields(None) is None
 
 
diff --git a/tests/backend/test_media_fuzzing.py b/tests/backend/test_media_fuzzing.py
index 469c835..93fa9ca 100644
--- a/tests/backend/test_media_fuzzing.py
+++ b/tests/backend/test_media_fuzzing.py
@@ -29,8 +29,10 @@ _JSON_LEAF = (
 def _recursive_json(max_leaves: int = 24):
     return st.recursive(
         _JSON_LEAF,
-        lambda children: st.lists(children, max_size=8)
-        | st.dictionaries(st.text(max_size=12), children, max_size=8),
+        lambda children: (
+            st.lists(children, max_size=8)
+            | st.dictionaries(st.text(max_size=12), children, max_size=8)
+        ),
         max_leaves=max_leaves,
     )
 
@@ -60,7 +62,9 @@ def test_parse_tgs_gzip_json_fuzz(payload):
     merged.setdefault("op", 60.0)
     merged.setdefault("w", 100)
     merged.setdefault("h", 100)
-    raw = gzip.compress(json.dumps(merged, default=str).encode("utf-8", errors="surrogateescape"))
+    raw = gzip.compress(
+        json.dumps(merged, default=str).encode("utf-8", errors="surrogateescape")
+    )
     if len(raw) > sticker_utils.MAX_ANIMATED_BYTES:
         raw = raw[: sticker_utils.MAX_ANIMATED_BYTES]
     try:
@@ -87,7 +91,18 @@ def test_parse_webm_fuzz_never_raises_unexpected(tail):
         st.none(),
         st.text(max_size=48),
         st.sampled_from(
-            ["png", "jpeg", "webp", "gif", "bmp", "tgs", "webm", "svg", "image/png", ""],
+            [
+                "png",
+                "jpeg",
+                "webp",
+                "gif",
+                "bmp",
+                "tgs",
+                "webm",
+                "svg",
+                "image/png",
+                "",
+            ],
         ),
     ),
     raw=st.binary(min_size=0, max_size=8192),
@@ -103,7 +118,9 @@ def test_extract_metadata_fuzz_never_raises(image_type, raw):
     typ=st.one_of(
         st.none(),
         st.text(max_size=48),
-        st.sampled_from(["png", "jpeg", "jpg", "webp", "gif", "bmp", "tgs", "webm", "svg", ""]),
+        st.sampled_from(
+            ["png", "jpeg", "jpg", "webp", "gif", "bmp", "tgs", "webm", "svg", ""]
+        ),
     ),
     strict=st.booleans(),
 )
@@ -148,7 +165,9 @@ def test_mime_for_image_type_fuzz_never_raises(t):
     description=st.one_of(st.none(), st.text(max_size=400)),
     pack_type=st.one_of(st.none(), st.text(max_size=40)),
 )
-def test_sticker_pack_sanitizers_fuzz_never_raises(title, short_name, description, pack_type):
+def test_sticker_pack_sanitizers_fuzz_never_raises(
+    title, short_name, description, pack_type
+):
     sticker_pack_utils.sanitize_pack_title(title)
     sticker_pack_utils.sanitize_pack_short_name(short_name)
     sticker_pack_utils.sanitize_pack_description(description)
@@ -234,7 +253,10 @@ def test_strict_tgs_from_structured_gzip_json_fuzz(inner):
 
 @settings(max_examples=150, deadline=None)
 @given(
-    b64=st.one_of(st.text(max_size=400), st.binary(max_size=200).map(lambda b: base64.b64encode(b).decode("ascii"))),
+    b64=st.one_of(
+        st.text(max_size=400),
+        st.binary(max_size=200).map(lambda b: base64.b64encode(b).decode("ascii")),
+    ),
 )
 def test_sticker_validate_export_document_sticker_rows_fuzz(b64):
     doc = {
diff --git a/tests/backend/test_meshchat_coverage.py b/tests/backend/test_meshchat_coverage.py
index c747537..31bc97d 100644
--- a/tests/backend/test_meshchat_coverage.py
+++ b/tests/backend/test_meshchat_coverage.py
@@ -452,7 +452,9 @@ def _build_wav_pcm16(samplerate=48000, duration_seconds=0.5, frequency=440.0):
         wf.setframerate(samplerate)
         frames = bytearray()
         for i in range(n_samples):
-            sample = int(0.3 * 32767 * math.sin(2 * math.pi * frequency * (i / samplerate)))
+            sample = int(
+                0.3 * 32767 * math.sin(2 * math.pi * frequency * (i / samplerate))
+            )
             frames.extend(struct.pack("<h", sample))
         wf.writeframes(bytes(frames))
     return buf.getvalue()
diff --git a/tests/backend/test_notification_user_facing_filter.py b/tests/backend/test_notification_user_facing_filter.py
index 4f6cfbe..4e56987 100644
--- a/tests/backend/test_notification_user_facing_filter.py
+++ b/tests/backend/test_notification_user_facing_filter.py
@@ -140,9 +140,7 @@ class TestRequireUserFacingFlag:
         )
         # Without ``require_user_facing`` the helper preserves its old behavior
         # so the conversation list (which renders reactions) is unaffected.
-        assert (
-            compute_lxmf_conversation_unread_from_latest_row(row) is True
-        )
+        assert compute_lxmf_conversation_unread_from_latest_row(row) is True
 
     def test_reaction_filtered_when_require_user_facing(self):
         row = _row(
diff --git a/tests/backend/test_rnode_download_firmware.py b/tests/backend/test_rnode_download_firmware.py
index ca141ee..ccf3a00 100644
--- a/tests/backend/test_rnode_download_firmware.py
+++ b/tests/backend/test_rnode_download_firmware.py
@@ -98,7 +98,9 @@ async def test_download_firmware_returns_zip_for_allowed_url(web_app):
         async with TestClient(TestServer(aio_app)) as client:
             r = await client.get(
                 "/api/v1/tools/rnode/download_firmware",
-                params={"url": "https://github.com/owner/repo/releases/download/v1/firmware.zip"},
+                params={
+                    "url": "https://github.com/owner/repo/releases/download/v1/firmware.zip"
+                },
             )
             assert r.status == 200
             assert r.headers.get("Content-Type", "").startswith("application/zip")
@@ -122,7 +124,9 @@ async def test_download_firmware_propagates_upstream_error_status(web_app):
         async with TestClient(TestServer(aio_app)) as client:
             r = await client.get(
                 "/api/v1/tools/rnode/download_firmware",
-                params={"url": "https://git.quad4.io/Reticulum/RNode_Firmware/releases/download/v1/firmware.zip"},
+                params={
+                    "url": "https://git.quad4.io/Reticulum/RNode_Firmware/releases/download/v1/firmware.zip"
+                },
             )
             assert r.status == 404
             body = await r.json()
@@ -140,7 +144,9 @@ async def test_download_firmware_returns_500_on_exception(web_app):
         async with TestClient(TestServer(aio_app)) as client:
             r = await client.get(
                 "/api/v1/tools/rnode/download_firmware",
-                params={"url": "https://github.com/owner/repo/releases/download/v1/firmware.zip"},
+                params={
+                    "url": "https://github.com/owner/repo/releases/download/v1/firmware.zip"
+                },
             )
             assert r.status == 500
             body = await r.json()
@@ -190,7 +196,12 @@ async def test_latest_release_returns_proxied_payload(web_app):
     aio_app = _build_aio_app(web_app)
     payload = {
         "tag_name": "v1.83",
-        "assets": [{"name": "rnode_firmware_heltec32v3.zip", "browser_download_url": "https://x/rnode.zip"}],
+        "assets": [
+            {
+                "name": "rnode_firmware_heltec32v3.zip",
+                "browser_download_url": "https://x/rnode.zip",
+            }
+        ],
     }
     fake_session = _FakeJsonSession(200, payload)