fix: Don't register berkelydb as a store if it is not available on the system (#2096)

This is so that it is simpler and easier to do something with all plugins without treating different plugins in different ways.

Also remove test code that tries to accommodate the plugin being present but not usable.

Fixes #1816

Author: eden-logistics

CHANGELOG.md

@@ -291,6 +291,24 @@ and will be removed for release.
 <!-- -->
 <!-- -->
 
+
+<!-- -->
+<!-- -->
+<!-- CHANGE BARRIER: START -->
+<!-- -->
+<!-- -->
+
+- Only register the `rdflib.plugins.stores.berkeleydb.BerkeleyDB` as a store
+  plugin if the `berkeleydb` module is present.
+  Closed [issue #1816](https://github.com/RDFLib/rdflib/issues/1816).
+  [PR #2096](https://github.com/RDFLib/rdflib/pull/2096).
+
+<!-- -->
+<!-- -->
+<!-- CHANGE BARRIER: END -->
+<!-- -->
+<!-- -->
+
 <!-- -->
 <!-- -->
 <!-- CHANGE BARRIER: START -->

rdflib/plugin.py

@@ -39,6 +39,7 @@
     overload,
 )
 
+import rdflib.plugins.stores.berkeleydb
 from rdflib.exceptions import Error
 from rdflib.parser import Parser
 from rdflib.query import (
@@ -179,6 +180,15 @@ def plugins(
 
 
 # Register Stores
+
+if rdflib.plugins.stores.berkeleydb.has_bsddb:
+    # Checks for BerkeleyDB before registering it
+    register(
+        "BerkeleyDB",
+        Store,
+        "rdflib.plugins.stores.berkeleydb",
+        "BerkeleyDB",
+    )
 register(
     "default",
     Store,
@@ -209,12 +219,7 @@ def plugins(
     "rdflib.plugins.stores.concurrent",
     "ConcurrentStore",
 )
-register(
-    "BerkeleyDB",
-    Store,
-    "rdflib.plugins.stores.berkeleydb",
-    "BerkeleyDB",
-)
+
 register(
     "SPARQLStore",
     Store,

test/test_graph/test_graph.py

@@ -13,7 +13,6 @@
 from rdflib.exceptions import ParserError
 from rdflib.namespace import Namespace, NamespaceManager
 from rdflib.plugin import PluginException
-from rdflib.plugins.stores.berkeleydb import has_bsddb
 from rdflib.store import Store
 from rdflib.term import BNode
 
@@ -75,8 +74,6 @@ def get_store_names() -> Set[Optional[str]]:
         }
     )
     names.add(None)
-    if not has_bsddb:
-        names.remove("BerkeleyDB")
 
     logging.debug("names = %s", names)
     return names