Remove error handler around find_all_candidates to see if it fails in…

… github actions ci

Run black over tests/unit/test_finder.py

src/pip/_internal/resolution/resolvelib/resolver.py

@@ -175,15 +175,8 @@ def _prime_finder_cache(self, project_names: Iterable[str]) -> None:
         in parallel in order to avoid later blocking on network requests during
         resolution.
         """
-
-        def _maybe_find_candidates(project_name: str) -> None:
-            try:
-                self._finder.find_all_candidates(project_name)
-            except AttributeError:
-                pass
-
         with ThreadPool() as tp:
-            for _ in tp.imap_unordered(_maybe_find_candidates, project_names):
+            for _ in tp.imap_unordered(self._finder.find_all_candidates, project_names):
                 pass
 
     def get_installation_order(

tests/unit/test_finder.py

@@ -569,7 +569,6 @@ def test_find_all_candidates_find_links_and_index(data: TestData) -> None:
 
 
 def test_finder_caching(data: TestData) -> None:
-
     # This is not required for the behavior of the finder itself, but we exploit
     # the implementation of the finder's find_best_candidate consuming it's own
     # find_all_candidates cache to pre-populate the cache before the resolution process