Helper and docs for offlinesales API (#5302)

src/pretix/testutils/queries.py

@@ -0,0 +1,55 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from django.db import DEFAULT_DB_ALIAS, connections
+from django.test.utils import CaptureQueriesContext
+
+
+class _AssertNumQueriesContext(CaptureQueriesContext):
+    # Inspired by /django/test/testcases.py
+    # but copied over to work without the unit test module
+    def __init__(self, num, connection):
+        self.num = num
+        super(_AssertNumQueriesContext, self).__init__(connection)
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        super(_AssertNumQueriesContext, self).__exit__(exc_type, exc_value, traceback)
+        if exc_type is not None:
+            return
+        executed = len(self)
+        assert executed == self.num, "%d queries executed, %d expected\nCaptured queries were:\n%s" % (
+            executed, self.num,
+            '\n'.join(
+                query['sql'] for query in self.captured_queries
+            )
+        )
+
+
+def assert_num_queries(num, func=None, *args, **kwargs):
+    using = kwargs.pop("using", DEFAULT_DB_ALIAS)
+    conn = connections[using]
+
+    context = _AssertNumQueriesContext(num, conn)
+    if func is None:
+        return context
+
+    with context:
+        func(*args, **kwargs)