1 files changed, 49 insertions, 0 deletions
diff --git a/toolkit/components/glean/tests/pytest/test_gifft.py b/toolkit/components/glean/tests/pytest/test_gifft.py
new file mode 100644
index 0000000000..5de0640bca
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_gifft.py
@@ -0,0 +1,49 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import io
+import sys
+from os import path
+from pathlib import Path
+
+import mozunit
+from expect_helper import expect
+
+# Shenanigans to import the FOG glean_parser runner
+FOG_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(path.join(FOG_ROOT_PATH, "build_scripts", "glean_parser_ext"))
+import run_glean_parser
+
+
+def test_gifft_codegen():
+    """
+    A regression test. Very fragile.
+    It generates C++ for GIFFT for metrics_test.yaml and compares it
+    byte-for-byte with expected output C++ files.
+    To generate new expected output files, set `UPDATE_EXPECT=1` when running the test suite:
+
+    UPDATE_EXPECT=1 mach test toolkit/components/glean/pytest
+    """
+
+    options = {"allow_reserved": False}
+    here_path = Path(path.dirname(__file__))
+    input_files = [here_path / "metrics_test.yaml"]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    for probe_type in ("Event", "Histogram", "Scalar"):
+        output_fd = io.StringIO()
+        cpp_fd = io.StringIO()
+        run_glean_parser.output_gifft_map(output_fd, probe_type, all_objs, cpp_fd)
+
+        expect(here_path / f"gifft_output_{probe_type}", output_fd.getvalue())
+
+        if probe_type == "Event":
+            expect(here_path / "gifft_output_EventExtra", cpp_fd.getvalue())
+
+
+if __name__ == "__main__":
+    mozunit.main()