Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 1429 insertions, 0 deletions

diff --git a/toolkit/components/telemetry/tests/python/python.ini b/toolkit/components/telemetry/tests/python/python.ini
new file mode 100644
index 0000000000..f2301537f9
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/python.ini
@@ -0,0 +1,10 @@
+[DEFAULT]
+subsuite = telemetry-python
+
+[test_gen_event_data_json.py]
+[test_gen_scalar_data_json.py]
+[test_histogramtools_non_strict.py]
+[test_histogramtools_strict.py]
+[test_parse_events.py]
+[test_parse_scalars.py]
+[test_usecounters.py]
diff --git a/toolkit/components/telemetry/tests/python/test_gen_event_data_json.py b/toolkit/components/telemetry/tests/python/test_gen_event_data_json.py
new file mode 100644
index 0000000000..3a2b374bf3
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_gen_event_data_json.py
@@ -0,0 +1,103 @@
+# 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 json
+import os
+import sys
+import tempfile
+import unittest
+from io import StringIO
+from os import path
+
+import mozunit
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The generators live in "build_scripts", account for that.
+# NOTE: if the generators are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+import gen_event_data  # noqa: E402
+
+
+class TestEventDataJson(unittest.TestCase):
+
+    maxDiff = None
+
+    def test_JSON_definitions_generation(self):
+        EVENTS_YAML = b"""
+with.optout:
+  testme1:
+    objects: ["test1"]
+    bug_numbers: [1456415]
+    notification_emails: ["telemetry-client-dev@mozilla.org"]
+    record_in_processes: ["main"]
+    description: opt-out event
+    release_channel_collection: opt-out
+    expiry_version: never
+    products:
+      - firefox
+    extra_keys:
+      message: a message 1
+with.optin:
+  testme2:
+    objects: ["test2"]
+    bug_numbers: [1456415]
+    notification_emails: ["telemetry-client-dev@mozilla.org"]
+    record_in_processes: ["main"]
+    description: opt-in event
+    release_channel_collection: opt-in
+    expiry_version: never
+    products: ['firefox', 'fennec']
+    extra_keys:
+      message: a message 2
+        """
+
+        EXPECTED_JSON = {
+            "with.optout": {
+                "testme1": {
+                    "objects": ["test1"],
+                    "expired": False,
+                    "expires": "never",
+                    "methods": ["testme1"],
+                    "extra_keys": ["message"],
+                    "record_on_release": True,
+                    "products": ["firefox"],
+                }
+            },
+            "with.optin": {
+                "testme2": {
+                    "objects": ["test2"],
+                    "expired": False,
+                    "expires": "never",
+                    "methods": ["testme2"],
+                    "extra_keys": ["message"],
+                    "record_on_release": False,
+                    "products": ["firefox", "fennec"],
+                }
+            },
+        }
+
+        io = StringIO()
+        try:
+            tmpfile = tempfile.NamedTemporaryFile(suffix=".json", delete=False)
+            # Write the event definition to the temporary file
+            tmpfile.write(EVENTS_YAML)
+            tmpfile.close()
+
+            # Let the parser generate the artifact definitions
+            gen_event_data.generate_JSON_definitions(io, tmpfile.name)
+        finally:
+            if tmpfile:
+                os.unlink(tmpfile.name)
+
+        event_definitions = json.loads(io.getvalue())
+
+        # Check that it generated the correct data
+        self.assertEqual(EXPECTED_JSON, event_definitions)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_gen_scalar_data_json.py b/toolkit/components/telemetry/tests/python/test_gen_scalar_data_json.py
new file mode 100644
index 0000000000..1db5558a2e
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_gen_scalar_data_json.py
@@ -0,0 +1,101 @@
+# 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 json
+import os
+import sys
+import tempfile
+import unittest
+from io import StringIO
+from os import path
+
+import mozunit
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The generators live in "build_scripts", account for that.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+import gen_scalar_data  # noqa: E402
+
+
+class TestScalarDataJson(unittest.TestCase):
+
+    maxDiff = None
+
+    def test_JSON_definitions_generation(self):
+        SCALARS_YAML = b"""
+newscalar:
+  withoptin:
+    bug_numbers:
+      - 1456415
+    description: opt-in scalar
+    expires: never
+    kind: uint
+    notification_emails: ["telemetry-client-dev@mozilla.org"]
+    record_in_processes: ["main"]
+    release_channel_collection: opt-in
+    products:
+      - firefox
+    keyed: false
+  withoptout:
+    bug_numbers:
+      - 1456415
+    description: opt-out scalar
+    expires: never
+    kind: string
+    notification_emails: ["telemetry-client-dev@mozilla.org"]
+    record_in_processes: ["main"]
+    release_channel_collection: opt-out
+    products: ["firefox", "fennec"]
+    keyed: false
+        """
+
+        EXPECTED_JSON = {
+            "newscalar": {
+                "withoptout": {
+                    "kind": "nsITelemetry::SCALAR_TYPE_STRING",
+                    "expired": False,
+                    "expires": "never",
+                    "record_on_release": True,
+                    "keyed": False,
+                    "keys": [],
+                    "stores": ["main"],
+                    "products": ["firefox", "fennec"],
+                },
+                "withoptin": {
+                    "kind": "nsITelemetry::SCALAR_TYPE_COUNT",
+                    "expired": False,
+                    "expires": "never",
+                    "record_on_release": False,
+                    "keyed": False,
+                    "keys": [],
+                    "stores": ["main"],
+                    "products": ["firefox"],
+                },
+            }
+        }
+
+        io = StringIO()
+        try:
+            tmpfile = tempfile.NamedTemporaryFile(suffix=".json", delete=False)
+            # Write the scalar definition to the temporary file
+            tmpfile.write(SCALARS_YAML)
+            tmpfile.close()
+
+            # Let the parser generate the artifact definitions
+            gen_scalar_data.generate_JSON_definitions(io, tmpfile.name)
+        finally:
+            if tmpfile:
+                os.unlink(tmpfile.name)
+
+        scalar_definitions = json.loads(io.getvalue())
+
+        # Check that it generated the correct data
+        self.assertEqual(EXPECTED_JSON, scalar_definitions)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_histogramtools_non_strict.py b/toolkit/components/telemetry/tests/python/test_histogramtools_non_strict.py
new file mode 100644
index 0000000000..275690735c
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_histogramtools_non_strict.py
@@ -0,0 +1,146 @@
+# 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 json
+import sys
+import unittest
+from os import path
+
+import mozunit
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The parsers live in a subdirectory of "build_scripts", account for that.
+# NOTE: if the parsers are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+from mozparsers import parse_histograms  # noqa: E402
+
+
+def load_histogram(histograms):
+    """Parse the passed Histogram and return a dictionary mapping histogram
+    names to histogram parameters.
+
+    :param histogram: Histogram as a python dictionary
+    :returns: Parsed Histogram dictionary mapping histogram names to histogram parameters
+    """
+
+    def hook(ps):
+        return parse_histograms.load_histograms_into_dict(ps, strict_type_checks=False)
+
+    return json.loads(json.dumps(histograms), object_pairs_hook=hook)
+
+
+class TestParser(unittest.TestCase):
+    def test_unknown_field(self):
+        SAMPLE_HISTOGRAM = {
+            "A11Y_INSTANTIATED_FLAG": {
+                "record_in_processes": ["main", "content"],
+                "expires_in_version": "never",
+                "kind": "flag",
+                "description": "has accessibility support been instantiated",
+                "new_field": "Its a new field",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+
+        hist = parse_histograms.Histogram(
+            "A11Y_INSTANTIATED_FLAG",
+            histograms["A11Y_INSTANTIATED_FLAG"],
+            strict_type_checks=False,
+        )
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "flag")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+
+    def test_non_numeric_expressions(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_NON_NUMERIC_HISTOGRAM": {
+                "kind": "linear",
+                "description": "sample",
+                "n_buckets": "JS::GCReason::NUM_TELEMETRY_REASONS",
+                "high": "mozilla::StartupTimeline::MAX_EVENT_ID",
+            }
+        }
+
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        hist = parse_histograms.Histogram(
+            "TEST_NON_NUMERIC_HISTOGRAM",
+            histograms["TEST_NON_NUMERIC_HISTOGRAM"],
+            strict_type_checks=False,
+        )
+
+        # expected values come off parse_histograms.py
+        self.assertEqual(hist.n_buckets(), 101)
+        self.assertEqual(hist.high(), 12)
+
+    def test_devtools_database_parsing(self):
+        db = path.join(
+            TELEMETRY_ROOT_PATH,
+            path.pardir,
+            path.pardir,
+            path.pardir,
+            "devtools",
+            "shared",
+            "css",
+            "generated",
+            "properties-db.js",
+        )
+
+        histograms = list(parse_histograms.from_files([db], strict_type_checks=False))
+        histograms = [h.name() for h in histograms]
+
+        # Test a shorthand (animation)
+        self.assertTrue("USE_COUNTER2_CSS_PROPERTY_Animation_DOCUMENT" in histograms)
+
+        # Test a shorthand alias (-moz-animation).
+        self.assertTrue("USE_COUNTER2_CSS_PROPERTY_MozAnimation_DOCUMENT" in histograms)
+
+        # Test a longhand (animation-name)
+        self.assertTrue(
+            "USE_COUNTER2_CSS_PROPERTY_AnimationName_DOCUMENT" in histograms
+        )
+
+        # Test a longhand alias (-moz-animation-name)
+        self.assertTrue(
+            "USE_COUNTER2_CSS_PROPERTY_MozAnimationName_DOCUMENT" in histograms
+        )
+
+    def test_current_histogram(self):
+        HISTOGRAMS_PATH = path.join(TELEMETRY_ROOT_PATH, "Histograms.json")
+        all_histograms = list(
+            parse_histograms.from_files([HISTOGRAMS_PATH], strict_type_checks=False)
+        )
+        test_histogram = [
+            i for i in all_histograms if i.name() == "TELEMETRY_TEST_FLAG"
+        ][0]
+
+        self.assertEqual(test_histogram.expiration(), "never")
+        self.assertEqual(test_histogram.kind(), "flag")
+        self.assertEqual(test_histogram.record_in_processes(), ["main", "content"])
+        self.assertEqual(test_histogram.keyed(), False)
+
+    def test_no_products(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_EMPTY_PRODUCTS": {
+                "kind": "flag",
+                "description": "sample",
+            }
+        }
+
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        hist = parse_histograms.Histogram(
+            "TEST_EMPTY_PRODUCTS",
+            histograms["TEST_EMPTY_PRODUCTS"],
+            strict_type_checks=False,
+        )
+
+        self.assertEqual(hist.kind(), "flag")
+        # bug 1486072: absent `product` key becomes None instead of ["all"]
+        self.assertEqual(hist.products(), None)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_histogramtools_strict.py b/toolkit/components/telemetry/tests/python/test_histogramtools_strict.py
new file mode 100644
index 0000000000..accafe90ad
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_histogramtools_strict.py
@@ -0,0 +1,566 @@
+# 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 os
+import sys
+import unittest
+from os import path
+
+import mozunit
+from test_histogramtools_non_strict import load_histogram
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The parsers live in a subdirectory of "build_scripts", account for that.
+# NOTE: if the parsers are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+from mozparsers import parse_histograms
+from mozparsers.shared_telemetry_utils import ParserError
+
+
+class TestParser(unittest.TestCase):
+    def setUp(self):
+        def mockexit(x):
+            raise SystemExit(x)
+
+        self.oldexit = os._exit
+        os._exit = mockexit
+
+    def tearDown(self):
+        os._exit = self.oldexit
+
+    def test_valid_histogram(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_VALID_HISTOGRAM": {
+                "record_in_processes": ["main", "content", "socket", "utility"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        hist = parse_histograms.Histogram(
+            "TEST_VALID_HISTOGRAM",
+            histograms["TEST_VALID_HISTOGRAM"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertTrue(hist.expiration(), "never")
+        self.assertTrue(hist.kind(), "boolean")
+        self.assertTrue(hist.record_in_processes, ["main", "content"])
+        self.assertTrue(hist.record_into_store, ["main"])
+
+    def test_missing_bug_numbers(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": [],
+            "bug_numbers": ["TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS"],
+            "n_buckets": [],
+            "expiry_default": [],
+            "kind": [],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_BUG_NUMBERS"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "boolean")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+
+        parse_histograms.allowlists = None
+
+    def test_missing_alert_emails(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS": {
+                "record_in_processes": ["main", "content"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": ["TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS"],
+            "bug_numbers": [],
+            "n_buckets": [],
+            "expiry_default": [],
+            "kind": [],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_ALERT_EMAILS"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "boolean")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+
+        parse_histograms.allowlists = None
+
+    def test_high_value(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "exponential",
+                "low": 1024,
+                "high": 2 ** 64,
+                "n_buckets": 100,
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_high_n_buckets(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "exponential",
+                "low": 1024,
+                "high": 16777216,
+                "n_buckets": 200,
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": [],
+            "bug_numbers": [],
+            "n_buckets": ["TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS"],
+            "expiry_default": [],
+            "kind": [],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_N_BUCKETS"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "exponential")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+        self.assertEqual(hist.low(), 1024)
+        self.assertEqual(hist.high(), 16777216)
+        self.assertEqual(hist.n_buckets(), 200)
+
+        parse_histograms.allowlists = None
+
+    def test_expiry_default(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT": {
+                "record_in_processes": ["main", "content"],
+                "expires_in_version": "default",
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "kind": "boolean",
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": [],
+            "bug_numbers": [],
+            "n_buckets": [],
+            "expiry_default": ["TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT"],
+            "kind": [],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_EXPIRY_DEFAULT"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "default")
+        self.assertEqual(hist.kind(), "boolean")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+
+        parse_histograms.allowlists = None
+
+    def test_unsupported_kind_count(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_KIND": {
+                "record_in_processes": ["main", "content"],
+                "expires_in_version": "never",
+                "kind": "count",
+                "releaseChannelCollection": "opt-out",
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        self.assertRaises(
+            SystemExit,
+            parse_histograms.Histogram,
+            "TEST_HISTOGRAM_ALLOWLIST_KIND",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+            strict_type_checks=True,
+        )
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": [],
+            "bug_numbers": [],
+            "n_buckets": [],
+            "expiry_default": [],
+            "kind": ["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_KIND",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "count")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+
+        parse_histograms.allowlists = None
+
+    def test_unsupported_kind_flag(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALLOWLIST_KIND": {
+                "record_in_processes": ["main", "content"],
+                "expires_in_version": "never",
+                "kind": "flag",
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        self.assertRaises(
+            SystemExit,
+            parse_histograms.Histogram,
+            "TEST_HISTOGRAM_ALLOWLIST_KIND",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+            strict_type_checks=True,
+        )
+
+        # Set global allowlists for parse_histograms.
+        parse_histograms.allowlists = {
+            "alert_emails": [],
+            "bug_numbers": [],
+            "n_buckets": [],
+            "expiry_default": [],
+            "kind": ["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+        }
+
+        hist = parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALLOWLIST_KIND",
+            histograms["TEST_HISTOGRAM_ALLOWLIST_KIND"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "flag")
+        self.assertEqual(hist.record_in_processes(), ["main", "content"])
+        self.assertEqual(hist.keyed(), False)
+
+        parse_histograms.allowlists = None
+
+    def test_multistore(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_VALID_HISTOGRAM": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+                "products": ["firefox"],
+                "record_into_store": ["main", "sync"],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        hist = parse_histograms.Histogram(
+            "TEST_VALID_HISTOGRAM",
+            histograms["TEST_VALID_HISTOGRAM"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertTrue(hist.expiration(), "never")
+        self.assertTrue(hist.kind(), "boolean")
+        self.assertTrue(hist.record_into_store, ["main", "sync"])
+
+    def test_multistore_empty(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_EMPTY_MULTISTORE": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+                "products": ["firefox"],
+                "record_into_store": [],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_EMPTY_MULTISTORE",
+            histograms["TEST_HISTOGRAM_EMPTY_MULTISTORE"],
+            strict_type_checks=True,
+        )
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_products_absent(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_NO_PRODUCTS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        def test_parse():
+            return parse_histograms.Histogram(
+                "TEST_NO_PRODUCTS",
+                histograms["TEST_NO_PRODUCTS"],
+                strict_type_checks=True,
+            )
+
+        self.assertRaises(SystemExit, test_parse)
+
+    def test_products_empty(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_EMPTY_PRODUCTS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+                "products": [],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        def test_parse():
+            return parse_histograms.Histogram(
+                "TEST_EMPTY_PRODUCTS",
+                histograms["TEST_EMPTY_PRODUCTS"],
+                strict_type_checks=True,
+            )
+
+        self.assertRaises(SystemExit, test_parse)
+
+    def test_products_all(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_ALL_PRODUCTS": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+                "products": ["all"],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_ALL_PRODUCTS",
+            histograms["TEST_HISTOGRAM_ALL_PRODUCTS"],
+            strict_type_checks=True,
+        )
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_gv_streaming_unsupported_kind(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_GV_STREAMING": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Test histogram",
+                "products": ["geckoview_streaming"],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_GV_STREAMING",
+            histograms["TEST_HISTOGRAM_GV_STREAMING"],
+            strict_type_checks=True,
+        )
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_gv_streaming_keyed(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_HISTOGRAM_GV_STREAMING": {
+                "record_in_processes": ["main", "content"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "exponential",
+                "low": 1024,
+                "high": 2 ** 64,
+                "n_buckets": 100,
+                "keyed": "true",
+                "description": "Test histogram",
+                "products": ["geckoview_streaming"],
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+        parse_histograms.Histogram(
+            "TEST_HISTOGRAM_GV_STREAMING",
+            histograms["TEST_HISTOGRAM_GV_STREAMING"],
+            strict_type_checks=True,
+        )
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_enumerated_histogram_with_100_buckets(self):
+        SAMPLE_HISTOGRAM = {
+            "TEST_100_BUCKETS_HISTOGRAM": {
+                "record_in_processes": ["main", "content", "socket", "utility"],
+                "alert_emails": ["team@mozilla.xyz"],
+                "bug_numbers": [1383793],
+                "expires_in_version": "never",
+                "kind": "enumerated",
+                "n_values": 100,
+                "products": ["firefox"],
+                "description": "Test histogram",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        hist = parse_histograms.Histogram(
+            "TEST_100_BUCKETS_HISTOGRAM",
+            histograms["TEST_100_BUCKETS_HISTOGRAM"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertTrue(hist.expiration(), "never")
+        self.assertTrue(hist.kind(), "enumerated")
+        self.assertTrue(hist.n_buckets(), 101)
+        self.assertTrue(hist.record_in_processes, ["main", "content"])
+        self.assertTrue(hist.record_into_store, ["main"])
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_parse_events.py b/toolkit/components/telemetry/tests/python/test_parse_events.py
new file mode 100644
index 0000000000..0b7b91efcc
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_parse_events.py
@@ -0,0 +1,166 @@
+# This Source Code Form is subject to the terms of 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 os
+import sys
+import unittest
+from os import path
+
+import mozunit
+import yaml
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The parsers live in a subdirectory of "build_scripts", account for that.
+# NOTE: if the parsers are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+from mozparsers import parse_events
+from mozparsers.shared_telemetry_utils import ParserError
+
+
+def load_event(event):
+    """Parse the passed event and return a dictionary
+
+    :param event: Event as YAML string
+    :returns: Parsed Event dictionary
+    """
+    return yaml.safe_load(event)
+
+
+class TestParser(unittest.TestCase):
+    def setUp(self):
+        def mockexit(x):
+            raise SystemExit(x)
+
+        self.oldexit = os._exit
+        os._exit = mockexit
+
+    def tearDown(self):
+        os._exit = self.oldexit
+
+    def test_valid_event_defaults(self):
+        SAMPLE_EVENT = """
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["main"]
+description: This is a test entry for Telemetry.
+products: ["firefox"]
+expiry_version: never
+"""
+        name = "test_event"
+        event = load_event(SAMPLE_EVENT)
+        evt = parse_events.EventData("CATEGORY", name, event, strict_type_checks=True)
+        ParserError.exit_func()
+
+        self.assertEqual(evt.methods, [name])
+        self.assertEqual(evt.record_in_processes, ["main"])
+        self.assertEqual(evt.objects, ["object1", "object2"])
+        self.assertEqual(evt.products, ["firefox"])
+        self.assertEqual(evt.operating_systems, ["all"])
+        self.assertEqual(evt.extra_keys, [])
+
+    def test_wrong_collection(self):
+        SAMPLE_EVENT = """
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["main"]
+description: This is a test entry for Telemetry.
+expiry_version: never
+products: ["firefox"]
+release_channel_collection: none
+"""
+        event = load_event(SAMPLE_EVENT)
+        parse_events.EventData("CATEGORY", "test_event", event, strict_type_checks=True)
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_valid_event_custom(self):
+        SAMPLE_EVENT = """
+methods: ["method1", "method2"]
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["content"]
+description: This is a test entry for Telemetry.
+expiry_version: never
+extra_keys:
+  key1: test1
+  key2: test2
+products:
+    - fennec
+operating_systems:
+    - windows
+"""
+        name = "test_event"
+        event = load_event(SAMPLE_EVENT)
+        evt = parse_events.EventData("CATEGORY", name, event, strict_type_checks=True)
+        ParserError.exit_func()
+
+        self.assertEqual(evt.methods, ["method1", "method2"])
+        self.assertEqual(evt.objects, ["object1", "object2"])
+        self.assertEqual(evt.record_in_processes, ["content"])
+        self.assertEqual(evt.products, ["fennec"])
+        self.assertEqual(evt.operating_systems, ["windows"])
+        self.assertEqual(sorted(evt.extra_keys), ["key1", "key2"])
+
+    def test_absent_products(self):
+        SAMPLE_EVENT = """
+methods: ["method1", "method2"]
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["content"]
+description: This is a test entry for Telemetry.
+expiry_version: never
+"""
+        event = load_event(SAMPLE_EVENT)
+        self.assertRaises(
+            SystemExit,
+            lambda: parse_events.EventData(
+                "CATEGORY", "test_event", event, strict_type_checks=True
+            ),
+        )
+
+    def test_empty_products(self):
+        SAMPLE_EVENT = """
+methods: ["method1", "method2"]
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["content"]
+description: This is a test entry for Telemetry.
+products: []
+expiry_version: never
+"""
+        event = load_event(SAMPLE_EVENT)
+        self.assertRaises(
+            SystemExit,
+            lambda: parse_events.EventData(
+                "CATEGORY", "test_event", event, strict_type_checks=True
+            ),
+        )
+
+    def test_geckoview_streaming_product(self):
+        SAMPLE_EVENT = """
+methods: ["method1", "method2"]
+objects: ["object1", "object2"]
+bug_numbers: [12345]
+notification_emails: ["test01@mozilla.com", "test02@mozilla.com"]
+record_in_processes: ["content"]
+description: This is a test entry for Telemetry.
+products: ["geckoview_streaming"]
+expiry_version: never
+"""
+        event = load_event(SAMPLE_EVENT)
+        parse_events.EventData("CATEGORY", "test_event", event, strict_type_checks=True)
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_parse_scalars.py b/toolkit/components/telemetry/tests/python/test_parse_scalars.py
new file mode 100644
index 0000000000..c699cdb4d8
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_parse_scalars.py
@@ -0,0 +1,267 @@
+# This Source Code Form is subject to the terms of 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 os
+import sys
+import unittest
+from os import path
+
+import mozunit
+import yaml
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The parsers live in a subdirectory of "build_scripts", account for that.
+# NOTE: if the parsers are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+from mozparsers import parse_scalars
+from mozparsers.shared_telemetry_utils import ParserError
+
+
+def load_scalar(scalar):
+    """Parse the passed Scalar and return a dictionary
+
+    :param scalar: Scalar as YAML string
+    :returns: Parsed Scalar dictionary
+    """
+    return yaml.safe_load(scalar)
+
+
+class TestParser(unittest.TestCase):
+    def setUp(self):
+        def mockexit(x):
+            raise SystemExit(x)
+
+        self.oldexit = os._exit
+        os._exit = mockexit
+
+    def tearDown(self):
+        os._exit = self.oldexit
+
+    def test_valid_email_address(self):
+        SAMPLE_SCALAR_VALID_ADDRESSES = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+  - test02@mozilla.com
+products: ["firefox"]
+bug_numbers:
+  - 12345
+"""
+        scalar = load_scalar(SAMPLE_SCALAR_VALID_ADDRESSES)
+        sclr = parse_scalars.ScalarType(
+            "CATEGORY", "PROVE", scalar, strict_type_checks=True
+        )
+        ParserError.exit_func()
+
+        self.assertEqual(
+            sclr.notification_emails, ["test01@mozilla.com", "test02@mozilla.com"]
+        )
+
+    def test_invalid_email_address(self):
+        SAMPLE_SCALAR_INVALID_ADDRESSES = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com, test02@mozilla.com
+products: ["firefox"]
+bug_numbers:
+  - 12345
+"""
+        scalar = load_scalar(SAMPLE_SCALAR_INVALID_ADDRESSES)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_multistore_default(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+products: ["firefox"]
+bug_numbers:
+  - 12345
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        sclr = parse_scalars.ScalarType(
+            "CATEGORY", "PROVE", scalar, strict_type_checks=True
+        )
+        ParserError.exit_func()
+
+        self.assertEqual(sclr.record_into_store, ["main"])
+
+    def test_multistore_extended(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+bug_numbers:
+  - 12345
+products: ["firefox"]
+record_into_store:
+    - main
+    - sync
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        sclr = parse_scalars.ScalarType(
+            "CATEGORY", "PROVE", scalar, strict_type_checks=True
+        )
+        ParserError.exit_func()
+
+        self.assertEqual(sclr.record_into_store, ["main", "sync"])
+
+    def test_multistore_empty(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+bug_numbers:
+  - 12345
+products: ["firefox"]
+record_into_store: []
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_operating_systems_default(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+products: ["firefox"]
+bug_numbers:
+  - 12345
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        sclr = parse_scalars.ScalarType(
+            "CATEGORY", "PROVE", scalar, strict_type_checks=True
+        )
+        ParserError.exit_func()
+
+        self.assertEqual(sclr.operating_systems, ["all"])
+
+    def test_operating_systems_custom(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+bug_numbers:
+  - 12345
+products: ["firefox"]
+operating_systems:
+    - windows
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        sclr = parse_scalars.ScalarType(
+            "CATEGORY", "PROVE", scalar, strict_type_checks=True
+        )
+        ParserError.exit_func()
+
+        self.assertEqual(sclr.operating_systems, ["windows"])
+
+    def test_operating_systems_empty(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+bug_numbers:
+  - 12345
+products: ["firefox"]
+operating_systems: []
+"""
+        scalar = load_scalar(SAMPLE_SCALAR)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_products_absent(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+bug_numbers:
+  - 12345
+"""
+
+        scalar = load_scalar(SAMPLE_SCALAR)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_products_empty(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+products: []
+bug_numbers:
+  - 12345
+"""
+
+        scalar = load_scalar(SAMPLE_SCALAR)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+    def test_gv_streaming_keyed(self):
+        SAMPLE_SCALAR = """
+description: A nice one-line description.
+expires: never
+record_in_processes:
+  - 'main'
+kind: uint
+notification_emails:
+  - test01@mozilla.com
+products: ['geckoview_streaming']
+keyed: true
+bug_numbers:
+  - 12345
+"""
+
+        scalar = load_scalar(SAMPLE_SCALAR)
+        parse_scalars.ScalarType("CATEGORY", "PROVE", scalar, strict_type_checks=True)
+        self.assertRaises(SystemExit, ParserError.exit_func)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/telemetry/tests/python/test_usecounters.py b/toolkit/components/telemetry/tests/python/test_usecounters.py
new file mode 100644
index 0000000000..643bba27d7
--- /dev/null
+++ b/toolkit/components/telemetry/tests/python/test_usecounters.py
@@ -0,0 +1,70 @@
+# 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 sys
+import unittest
+from os import path
+
+import mozunit
+from test_histogramtools_non_strict import load_histogram
+
+TELEMETRY_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(TELEMETRY_ROOT_PATH)
+# The parsers live in a subdirectory of "build_scripts", account for that.
+# NOTE: if the parsers are moved, this logic will need to be updated.
+sys.path.append(path.join(TELEMETRY_ROOT_PATH, "build_scripts"))
+from mozparsers import parse_histograms
+from mozparsers.shared_telemetry_utils import ParserError
+
+
+class TestParser(unittest.TestCase):
+    def test_usecounter_collection_enabled(self):
+        SAMPLE_HISTOGRAM = {
+            "USE_COUNTER2_TEST_HISTOGRAM": {
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Whether a foo used bar",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        hist = parse_histograms.Histogram(
+            "USE_COUNTER2_TEST_HISTOGRAM",
+            histograms["USE_COUNTER2_TEST_HISTOGRAM"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.dataset(), "nsITelemetry::DATASET_ALL_CHANNELS")
+        self.assertEqual(hist.products(), ["firefox", "fennec"])
+
+    def test_usecounter_histogram(self):
+        SAMPLE_HISTOGRAM = {
+            "USE_COUNTER2_TEST_HISTOGRAM": {
+                "expires_in_version": "never",
+                "kind": "boolean",
+                "description": "Whether a foo used bar",
+            }
+        }
+        histograms = load_histogram(SAMPLE_HISTOGRAM)
+        parse_histograms.load_allowlist()
+
+        hist = parse_histograms.Histogram(
+            "USE_COUNTER2_TEST_HISTOGRAM",
+            histograms["USE_COUNTER2_TEST_HISTOGRAM"],
+            strict_type_checks=True,
+        )
+
+        ParserError.exit_func()
+        self.assertEqual(hist.expiration(), "never")
+        self.assertEqual(hist.kind(), "boolean")
+        self.assertEqual(hist.description(), "Whether a foo used bar")
+        self.assertEqual(hist.products(), ["firefox", "fennec"])
+
+
+if __name__ == "__main__":
+    mozunit.main()