[settings][test] Use the full path to the database as database name

This mimicks the Linux behaviour and allows to properly run the
beat/beat.cmdline tests on macOS.

beat/web/settings/test.py

@@ -48,7 +48,9 @@ if platform.system() == "Linux":
 
     database_name = os.path.join(shm_path, "test.sqlite3")
 else:
-    database_name = "test.sqlite3"
+    here = os.path.dirname(os.path.realpath(__file__))
+    database_name = os.path.join(here, "test.sqlite3")
+
 DATABASES["default"]["NAME"] = database_name  # noqa
 DATABASES["default"]["TEST"] = {"NAME": DATABASES["default"]["NAME"]}  # noqa
 DATABASES["default"]["OPTIONS"]["timeout"] = 30  # noqa