[test] Refactor initialization to make it more reusable

beat/beat.cmdline re-implements similar parts so
make them reusable

beat/core/test/__init__.py

@@ -59,8 +59,6 @@ else:
 
 prefix = os.path.join(prefix_folder, "prefix")
 
-BC_DATABASE_ROOT_FOLDER = os.path.join(prefix_folder, "beat_core_test")
-
 DOCKER_NETWORK_TEST_ENABLED = (
     os.environ.get("DOCKER_NETWORK_TEST_ENABLED", False) == "True"
 )
@@ -87,18 +85,15 @@ if VERBOSE_TEST_LOGGING:
         logger.addHandler(handler)
 
 
-def setup_package():
-    prefixes = [
-        pkg_resources.resource_filename("beat.backend.python.test", "prefix"),
-        pkg_resources.resource_filename("beat.core.test", "prefix"),
-    ]
+def sync_prefixes(source_prefixes, target_prefix):
+    for path in source_prefixes:
+        sp.check_call(["rsync", "-arz", path, target_prefix])
 
-    for path in prefixes:
-        sp.check_call(["rsync", "-arz", path, prefix_folder])
 
-    os.makedirs(BC_DATABASE_ROOT_FOLDER, exist_ok=True)
+def initialize_db_root_folder(database_root_folder, databases_path):
+    os.makedirs(database_root_folder, exist_ok=True)
 
-    for root, dirs, files in os.walk(os.path.join(prefix, "databases"), topdown=False):
+    for root, dirs, files in os.walk(databases_path, topdown=False):
         for file_ in files:
             if file_.endswith(".json"):
                 path = os.path.join(root, file_)
@@ -109,10 +104,24 @@ def setup_package():
                     # some are explicitly invalid.
                     continue
                 else:
-                    declaration["root_folder"] = BC_DATABASE_ROOT_FOLDER
+                    declaration["root_folder"] = database_root_folder
                     with open(path, "wt") as db_file:
                         json.dump(declaration, db_file, indent=4)
 
+
+def setup_package():
+    sync_prefixes(
+        [
+            pkg_resources.resource_filename("beat.backend.python.test", "prefix"),
+            pkg_resources.resource_filename("beat.core.test", "prefix"),
+        ],
+        prefix_folder,
+    )
+
+    initialize_db_root_folder(
+        os.path.join(prefix_folder, "beat_core_test"), os.path.join(prefix, "databases")
+    )
+
     if DOCKER_NETWORK_TEST_ENABLED:
         import docker