[MISC] Increase coverage (#505)

* Bump libs

* Tweak asserts

* Bump topology coverage

* Increase charm coverage

* Increase coverage on charm

* Bump libs

lib/charms/postgresql_k8s/v0/postgresql.py

@@ -36,7 +36,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 28
+LIBPATCH = 29
 
 INVALID_EXTRA_USER_ROLE_BLOCKING_MESSAGE = "invalid role(s) for extra user roles"
 
@@ -604,12 +604,11 @@ def build_postgresql_parameters(
                 # Use 25% of the available memory for shared_buffers.
                 # and the remaining as cache memory.
                 shared_buffers = int(available_memory * 0.25)
+                parameters["shared_buffers"] = f"{int(shared_buffers * 128 / 10**6)}"
             effective_cache_size = int(available_memory - shared_buffers)
-            parameters.setdefault("shared_buffers", f"{int(shared_buffers / 10**6)}MB")
-            parameters.update({"effective_cache_size": f"{int(effective_cache_size / 10**6)}MB"})
-        else:
-            # Return default
-            parameters.setdefault("shared_buffers", "128MB")
+            parameters.update({
+                "effective_cache_size": f"{int(effective_cache_size / 10**6) * 128}"
+            })
         return parameters
 
     def validate_date_style(self, date_style: str) -> bool:

lib/charms/postgresql_k8s/v0/postgresql_tls.py

@@ -34,6 +34,7 @@
 from ops.charm import ActionEvent, RelationBrokenEvent
 from ops.framework import Object
 from ops.pebble import ConnectionError, PathError, ProtocolError
+from tenacity import RetryError
 
 # The unique Charmhub library identifier, never change it
 LIBID = "c27af44a92df4ef38d7ae06418b2800f"
@@ -43,7 +44,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version.
-LIBPATCH = 8
+LIBPATCH = 9
 
 logger = logging.getLogger(__name__)
 SCOPE = "unit"
@@ -142,7 +143,7 @@ def _on_certificate_available(self, event: CertificateAvailableEvent) -> None:
                 logger.debug("Cannot push TLS certificates at this moment")
                 event.defer()
                 return
-        except (ConnectionError, PathError, ProtocolError) as e:
+        except (ConnectionError, PathError, ProtocolError, RetryError) as e:
             logger.error("Cannot push TLS certificates: %r", e)
             event.defer()
             return