Skip non-registered or non-supported backends (#487)

* Skip non-accessible/existing repos

* Adjust test to run under all Python versions

audb/core/api.py

@@ -101,7 +101,7 @@ def add_database(name: str, version: str, repository: Repository):
                             name = path.split("/")[1]
                             add_database(name, version, repository)
 
-        except audbackend.BackendError:
+        except (audbackend.BackendError, ValueError):
             continue
 
     df = pd.DataFrame.from_records(
@@ -635,7 +635,7 @@ def versions(
                             suppress_backend_errors=True,
                         )
                     )
-        except audbackend.BackendError:
+        except (audbackend.BackendError, ValueError):
             # If the backend cannot be accessed,
             # e.g. host or repository do not exist,
             # we skip it

audb/core/utils.py

@@ -91,7 +91,7 @@ def _lookup(
         try:
             backend_interface = repository.create_backend_interface()
             backend_interface.backend.open()
-        except audbackend.BackendError:
+        except (audbackend.BackendError, ValueError):
             continue
 
         header = backend_interface.join("/", name, "db.yaml")

tests/test_api.py

@@ -22,11 +22,22 @@ def test_available(repository):
     # Non existing repo
     name = "non-existing-repo"
     audb.config.REPOSITORIES = [
-        audb.Repository(
-            name=name,
-            host=repository.host,
-            backend=repository.backend,
-        )
+        audb.Repository(name, repository.host, repository.backend)
+    ]
+    df = audb.available()
+    assert len(df) == 0
+
+    # Non existing backend
+    audb.config.REPOSITORIES = [
+        audb.Repository(repository.name, repository.host, "custom")
+    ]
+    df = audb.available()
+    assert len(df) == 0
+
+    # artifactory backend with non-existing host,
+    # and non-support under Python>=3.12
+    audb.config.REPOSITORIES = [
+        audb.Repository("repo", "https:artifactory.url.com", "artifactory")
     ]
     df = audb.available()
     assert len(df) == 0