Playwright tests to replace old loading-test.tsx (#12654)

A selection of Playwright tests intended to replace the old Jest tests in
Element-Web's `loading-test.tsx`.

playwright/plugins/homeserver/synapse/templates/guest-enabled/log.config

@@ -0,0 +1,50 @@
+# Log configuration for Synapse.
+#
+# This is a YAML file containing a standard Python logging configuration
+# dictionary. See [1] for details on the valid settings.
+#
+# Synapse also supports structured logging for machine readable logs which can
+# be ingested by ELK stacks. See [2] for details.
+#
+# [1]: https://docs.python.org/3.7/library/logging.config.html#configuration-dictionary-schema
+# [2]: https://matrix-org.github.io/synapse/latest/structured_logging.html
+
+version: 1
+
+formatters:
+    precise:
+        format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
+
+handlers:
+    # A handler that writes logs to stderr. Unused by default, but can be used
+    # instead of "buffer" and "file" in the logger handlers.
+    console:
+        class: logging.StreamHandler
+        formatter: precise
+
+loggers:
+    synapse.storage.SQL:
+        # beware: increasing this to DEBUG will make synapse log sensitive
+        # information such as access tokens.
+        level: INFO
+
+    twisted:
+        # We send the twisted logging directly to the file handler,
+        # to work around https://github.com/matrix-org/synapse/issues/3471
+        # when using "buffer" logger. Use "console" to log to stderr instead.
+        handlers: [console]
+        propagate: false
+
+root:
+    level: INFO
+
+    # Write logs to the `buffer` handler, which will buffer them together in memory,
+    # then write them to a file.
+    #
+    # Replace "buffer" with "console" to log to stderr instead. (Note that you'll
+    # also need to update the configuration for the `twisted` logger above, in
+    # this case.)
+    #
+    handlers: [console]
+
+disable_existing_loggers: false