Fix flake8 complaints

.flake8

@@ -37,6 +37,7 @@ exclude = .*,__pycache__,resources.py
 #       (numpy-style)
 # D413: Missing blank line after last section (not in pep257?)
 # A003: Builtin name for class attribute (needed for overridden methods)
+# W503: like break before binary operator
 # W504: line break after binary operator
 ignore =
     B001,B008,B305,
@@ -46,7 +47,7 @@ ignore =
     P101,P102,P103,
     D102,D103,D106,D107,D104,D105,D209,D211,D401,D402,D403,D412,D413,
     A003,
-    W504
+    W503, W504
 min-version = 3.4.0
 max-complexity = 12
 per-file-ignores =

qutebrowser/components/braveadblock.py

@@ -42,7 +42,7 @@ from qutebrowser.api.interceptor import ResourceType
 
 
 logger = logging.getLogger("misc")
-_ad_blocker = typing.cast(typing.Optional['BraveAdBlocker'], None)
+_ad_blocker = typing.cast(typing.Optional["BraveAdBlocker"], None)
 
 
 def _is_whitelisted_url(url: QUrl) -> bool:
@@ -65,31 +65,33 @@ def _is_whitelisted_url(url: QUrl) -> bool:
     return False
 
 
+MAP_FROM_RESOURCE_TYPE_TO_STRING = {
+    ResourceType.main_frame: "main_frame",
+    ResourceType.sub_frame: "sub_frame",
+    ResourceType.stylesheet: "stylesheet",
+    ResourceType.script: "script",
+    ResourceType.image: "image",
+    ResourceType.font_resource: "font",
+    ResourceType.sub_resource: "sub_frame",
+    ResourceType.object: "object",
+    ResourceType.media: "media",
+    ResourceType.worker: "other",
+    ResourceType.shared_worker: "other",
+    ResourceType.prefetch: "other",
+    ResourceType.favicon: "image",
+    ResourceType.xhr: "xhr",
+    ResourceType.ping: "ping",
+    ResourceType.service_worker: "other",
+    ResourceType.csp_report: "csp_report",
+    ResourceType.plugin_resource: "other",
+    ResourceType.preload_main_frame: "other",
+    ResourceType.preload_sub_frame: "other",
+    ResourceType.unknown: "other",
+}
+
+
 def resource_type_to_string(resource_type: ResourceType) -> str:
-    MAP = {
-        ResourceType.main_frame: "main_frame",
-        ResourceType.sub_frame: "sub_frame",
-        ResourceType.stylesheet: "stylesheet",
-        ResourceType.script: "script",
-        ResourceType.image: "image",
-        ResourceType.font_resource: "font",
-        ResourceType.sub_resource: "sub_frame",
-        ResourceType.object: "object",
-        ResourceType.media: "media",
-        ResourceType.worker: "other",
-        ResourceType.shared_worker: "other",
-        ResourceType.prefetch: "other",
-        ResourceType.favicon: "image",
-        ResourceType.xhr: "xhr",
-        ResourceType.ping: "ping",
-        ResourceType.service_worker: "other",
-        ResourceType.csp_report: "csp_report",
-        ResourceType.plugin_resource: "other",
-        ResourceType.preload_main_frame: "other",
-        ResourceType.preload_sub_frame: "other",
-        ResourceType.unknown: "other",
-    }
-    return MAP.get(resource_type, "other")
+    return MAP_FROM_RESOURCE_TYPE_TO_STRING.get(resource_type, "other")
 
 
 # TODO: Move this code somewhere so that `adblock.py` can make use of it too.

tests/unit/components/test_braveadblock.py

@@ -60,17 +60,18 @@ def ad_blocker_factory(config_tmpdir, data_tmpdir, download_stub, config_stub):
 
 
 def test_dataset(ad_blocker_factory):
-    """
-    In the data folder, we have a file called `adblock_dataset.tsv`, which
-    contains tuples of (url, source_url, type) in each line.
+    """Run the ad-blocking logic on a bunch of urls.
 
-    Thus, this test is only meant to catch syntax errors and the like, not
+    In the data folder, we have a file called `adblock_dataset.tsv`, which
+    contains tuples of (url, source_url, type) in each line. We run these
+    through the ad blocker to see if we get any exceptions.
+
+    This test is only meant to catch syntax errors and the like, not
     incorrectness in the adblocker. There are thus no assert statements.
     """
+
     def dataset_type_to_enum(type_int: int) -> ResourceType:
-        """
-        Translate
-        """
+        """Translate the dataset's encoding of a resource type to Qutebrowser's."""
         if type_int == 0:
             return ResourceType.unknown
         elif type_int == 1: