1 files changed, 75 insertions, 0 deletions
diff --git a/toolkit/components/glean/pytest/test_glean_parser_js.py b/toolkit/components/glean/pytest/test_glean_parser_js.py
new file mode 100644
index 0000000000..09ba623fcf
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+++ b/toolkit/components/glean/pytest/test_glean_parser_js.py
@@ -0,0 +1,75 @@
+# 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 mozunit
+from os import path
+from pathlib import Path
+import sys
+
+
+# Shenanigans to import the js outputter extension
+FOG_ROOT_PATH = path.abspath(path.join(path.dirname(__file__), path.pardir))
+sys.path.append(path.join(FOG_ROOT_PATH, "build_scripts", "glean_parser_ext"))
+import js
+
+# Shenanigans to import the in-tree glean_parser
+GECKO_PATH = path.join(FOG_ROOT_PATH, path.pardir, path.pardir, path.pardir)
+sys.path.append(path.join(GECKO_PATH, "third_party", "python", "glean_parser"))
+from glean_parser import lint, parser, util
+
+
+def test_all_metric_types():
+    """Honestly, this is a pretty bad test.
+    It generates C++ for a given test metrics.yaml and compares it byte-for-byte
+    with an expected output C++ file.
+    Expect it to be fragile.
+    To generate a new expected output file, copy the test yaml over the one in t/c/g,
+    run mach build, then copy the C++ output from objdir/t/c/g/.
+    """
+
+    options = {"allow_reserved": False}
+    input_files = [Path(path.join(path.dirname(__file__), "metrics_test.yaml"))]
+
+    all_objs = parser.parse_objects(input_files, options)
+    assert not util.report_validation_errors(all_objs)
+    assert not lint.lint_metrics(all_objs.value, options)
+
+    output_fd = io.StringIO()
+    js.output_js(all_objs.value, output_fd, options)
+
+    with open(path.join(path.dirname(__file__), "metrics_test_output_js"), "r") as file:
+        EXPECTED_JS = file.read()
+    assert output_fd.getvalue() == EXPECTED_JS
+
+
+def test_fake_pings():
+    """Another similarly-fragile test.
+    It generates C++ for pings_test.yaml, comparing it byte-for-byte
+    with an expected output C++ file `pings_test_output_js`.
+    Expect it to be fragile.
+    To generate a new expected output file, edit t/c/g/metrics_index.py,
+    comment out all other ping yamls, and add one for
+    t/c/g/pytest/pings_test.yaml. Run `mach build` (it'll fail). Copy
+    objdir/t/c/g/GleanJSPingsLookup.h over pings_test_output_js.
+    (Don't forget to undo your edits to t/c/g/metrics_index.py)
+    """
+
+    options = {"allow_reserved": False}
+    input_files = [Path(path.join(path.dirname(__file__), "pings_test.yaml"))]
+
+    all_objs = parser.parse_objects(input_files, options)
+    assert not util.report_validation_errors(all_objs)
+    assert not lint.lint_metrics(all_objs.value, options)
+
+    output_fd = io.StringIO()
+    js.output_js(all_objs.value, output_fd, options)
+
+    with open(path.join(path.dirname(__file__), "pings_test_output_js"), "r") as file:
+        EXPECTED_JS = file.read()
+    assert output_fd.getvalue() == EXPECTED_JS
+
+
+if __name__ == "__main__":
+    mozunit.main()