Adding upstream version 124.0.1.upstream/124.0.1

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

25 files changed, 3824 insertions, 0 deletions

diff --git a/toolkit/components/glean/tests/pytest/expect_helper.py b/toolkit/components/glean/tests/pytest/expect_helper.py
new file mode 100644
index 0000000000..543ef04026
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/expect_helper.py
@@ -0,0 +1,34 @@
+# 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 inspect
+import os
+
+
+def expect(path, actual):
+    """
+    Assert that the content of the file at `path` contains `actual`.
+
+    If the environment variable `UPDATE_EXPECT` is set, the path content is updated to `actual`.
+    This allows to update the file contents easily.
+    """
+
+    callerframerecord = inspect.stack()[1]
+    frame = callerframerecord[0]
+    info = inspect.getframeinfo(frame)
+    msg = f"""
+Unexpected content in {path} (at {info.filename}:{info.lineno})
+
+If the code generation was changed,
+run the test suite again with `UPDATE_EXPECT=1` set to update the test files.
+""".strip()
+
+    if "UPDATE_EXPECT" in os.environ:
+        with open(path, "w") as file:
+            file.write(actual)
+
+    expected = None
+    with open(path, "r") as file:
+        expected = file.read()
+    assert actual == expected, msg
diff --git a/toolkit/components/glean/tests/pytest/gifft_output_Event b/toolkit/components/glean/tests/pytest/gifft_output_Event
new file mode 100644
index 0000000000..ba80e3300b
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/gifft_output_Event
@@ -0,0 +1,67 @@
+// -*- mode: C++ -*-
+
+/* This file is auto-generated by run_glean_parser.py.
+   It is only for internal use by types in
+   toolkit/components/glean/bindings/private */
+
+#include "mozilla/AppShutdown.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/glean/bindings/GleanJSMetricsLookup.h"
+#include "mozilla/glean/bindings/jog/JOG.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Telemetry.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+
+#ifndef mozilla_glean_EventGifftMap_h
+#define mozilla_glean_EventGifftMap_h
+
+#define DYNAMIC_METRIC_BIT (26)
+#define GLEAN_METRIC_ID(id) ((id) & ((1ULL << 27) - 1))
+
+namespace mozilla::glean {
+
+using Telemetry::EventID;
+
+
+static inline Maybe<EventID> EventIdForMetric(uint32_t aId) {
+  switch(aId) {
+    case 17: { // test.nested.event_metric
+      return Some(EventID::EventMetric_EnumNames_AreStrange);
+    }
+    case 18: { // test.nested.event_metric_with_extra
+      return Some(EventID::EventMetric_EnumName_WithExtra);
+    }
+    default: {
+      if (MOZ_UNLIKELY(aId & (1 << DYNAMIC_METRIC_BIT))) {
+        // Dynamic (runtime-registered) metric. Use its static (compiletime-
+        // registered) metric's telemetry_mirror mapping.
+        // ...if applicable.
+
+        // Only JS can use dynamic (runtime-registered) metric ids.
+        MOZ_ASSERT(NS_IsMainThread());
+
+        auto metricName = JOG::GetMetricName(aId);
+        // All of these should have names, but the storage only lasts until
+        // XPCOMWillShutdown, so it might return `Nothing()`.
+        if (metricName.isSome()) {
+          auto maybeMetric = MetricByNameLookup(metricName.ref());
+          if (maybeMetric.isSome()) {
+            uint32_t staticId = GLEAN_METRIC_ID(maybeMetric.value());
+            // Let's ensure we don't infinite loop, huh.
+            MOZ_ASSERT(!(staticId & (1 << DYNAMIC_METRIC_BIT)));
+            return EventIdForMetric(staticId);
+          }
+        }
+      }
+      return Nothing();
+    }
+  }
+}
+
+}  // namespace mozilla::glean
+
+#undef GLEAN_METRIC_ID
+#undef DYNAMIC_METRIC_BIT
+
+#endif  // mozilla_glean_EventGifftMaps_h
diff --git a/toolkit/components/glean/tests/pytest/gifft_output_EventExtra b/toolkit/components/glean/tests/pytest/gifft_output_EventExtra
new file mode 100644
index 0000000000..f5f2671d99
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/gifft_output_EventExtra
@@ -0,0 +1,35 @@
+// -*- mode: C++ -*-
+
+/* This file is auto-generated by run_glean_parser.py.
+   It is only for internal use by types in
+   toolkit/components/glean/bindings/private */
+
+#include "mozilla/glean/bindings/Event.h"
+#include "mozilla/glean/GleanMetrics.h"
+
+namespace mozilla::glean {
+
+template <>
+/*static*/ const nsCString impl::EventMetric<NoExtraKeys>::ExtraStringForKey(uint32_t aKey) {
+  MOZ_ASSERT_UNREACHABLE("What are you doing here? No extra keys!");
+  return ""_ns;
+}
+
+template <>
+/*static*/ const nsCString impl::EventMetric<test_nested::EventMetricWithExtraExtra>::ExtraStringForKey(uint32_t aKey) {
+  using test_nested::EventMetricWithExtraExtra;
+  switch (aKey) {
+    case 0: {
+      return "an_extra_key"_ns;
+    }
+    case 1: {
+      return "another_extra_key"_ns;
+    }
+    default: {
+      MOZ_ASSERT_UNREACHABLE("Impossible event key reached.");
+      return ""_ns;
+    }
+  }
+}
+
+};  // namespace mozilla::glean
diff --git a/toolkit/components/glean/tests/pytest/gifft_output_Histogram b/toolkit/components/glean/tests/pytest/gifft_output_Histogram
new file mode 100644
index 0000000000..40a33dd27f
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/gifft_output_Histogram
@@ -0,0 +1,70 @@
+// -*- mode: C++ -*-
+
+/* This file is auto-generated by run_glean_parser.py.
+   It is only for internal use by types in
+   toolkit/components/glean/bindings/private */
+
+#include "mozilla/AppShutdown.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/glean/bindings/GleanJSMetricsLookup.h"
+#include "mozilla/glean/bindings/jog/JOG.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Telemetry.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+
+#ifndef mozilla_glean_HistogramGifftMap_h
+#define mozilla_glean_HistogramGifftMap_h
+
+#define DYNAMIC_METRIC_BIT (26)
+#define GLEAN_METRIC_ID(id) ((id) & ((1ULL << 27) - 1))
+
+namespace mozilla::glean {
+
+using Telemetry::HistogramID;
+
+
+static Maybe<HistogramID> HistogramIdForMetric(uint32_t aId) {
+  switch(aId) {
+    case 3: { // test.custom_distribution_metric
+      return Some(HistogramID::SOME_LINEAR_HISTOGRAM);
+    }
+    case 10: { // test.memory_distribution_metric
+      return Some(HistogramID::SOME_MEM_HISTOGRAM_KB);
+    }
+    case 15: { // test.timing_distribution_metric
+      return Some(HistogramID::SOME_TIME_HISTOGRAM_MS);
+    }
+    default: {
+      if (MOZ_UNLIKELY(aId & (1 << DYNAMIC_METRIC_BIT))) {
+        // Dynamic (runtime-registered) metric. Use its static (compiletime-
+        // registered) metric's telemetry_mirror mapping.
+        // ...if applicable.
+
+        // Only JS can use dynamic (runtime-registered) metric ids.
+        MOZ_ASSERT(NS_IsMainThread());
+
+        auto metricName = JOG::GetMetricName(aId);
+        // All of these should have names, but the storage only lasts until
+        // XPCOMWillShutdown, so it might return `Nothing()`.
+        if (metricName.isSome()) {
+          auto maybeMetric = MetricByNameLookup(metricName.ref());
+          if (maybeMetric.isSome()) {
+            uint32_t staticId = GLEAN_METRIC_ID(maybeMetric.value());
+            // Let's ensure we don't infinite loop, huh.
+            MOZ_ASSERT(!(staticId & (1 << DYNAMIC_METRIC_BIT)));
+            return HistogramIdForMetric(staticId);
+          }
+        }
+      }
+      return Nothing();
+    }
+  }
+}
+
+}  // namespace mozilla::glean
+
+#undef GLEAN_METRIC_ID
+#undef DYNAMIC_METRIC_BIT
+
+#endif  // mozilla_glean_HistogramGifftMaps_h
diff --git a/toolkit/components/glean/tests/pytest/gifft_output_Scalar b/toolkit/components/glean/tests/pytest/gifft_output_Scalar
new file mode 100644
index 0000000000..854455b584
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/gifft_output_Scalar
@@ -0,0 +1,102 @@
+// -*- mode: C++ -*-
+
+/* This file is auto-generated by run_glean_parser.py.
+   It is only for internal use by types in
+   toolkit/components/glean/bindings/private */
+
+#include "mozilla/AppShutdown.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/glean/bindings/GleanJSMetricsLookup.h"
+#include "mozilla/glean/bindings/jog/JOG.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/Telemetry.h"
+#include "nsIThread.h"
+#include "nsThreadUtils.h"
+
+#ifndef mozilla_glean_ScalarGifftMap_h
+#define mozilla_glean_ScalarGifftMap_h
+
+#define DYNAMIC_METRIC_BIT (26)
+#define GLEAN_METRIC_ID(id) ((id) & ((1ULL << 27) - 1))
+
+namespace mozilla::glean {
+
+using Telemetry::ScalarID;
+
+static inline bool IsSubmetricId(uint32_t aId) {
+  // Submetrics have the 2^25 bit set.
+  // (ID_BITS - ID_SIGNAL_BITS, keep it in sync with js.py).
+  return (aId & (1 << 25)) > 0;
+}
+
+static inline Maybe<ScalarID> ScalarIdForMetric(uint32_t aId) {
+  switch(aId) {
+    case 1: { // test.boolean_metric
+      return Some(ScalarID::SOME_BOOL_SCALAR);
+    }
+    case 2: { // test.counter_metric
+      return Some(ScalarID::SOME_UINT_SCALAR);
+    }
+    case 4: { // test.labeled_boolean_metric
+      return Some(ScalarID::SOME_KEYED_BOOL_SCALAR);
+    }
+    case 5: { // test.labeled_boolean_metric_labels
+      return Some(ScalarID::SOME_OTHER_KEYED_BOOL_SCALAR);
+    }
+    case 6: { // test.labeled_counter_metric
+      return Some(ScalarID::SOME_KEYED_UINT_SCALAR);
+    }
+    case 7: { // test.labeled_counter_metric_labels
+      return Some(ScalarID::SOME_OTHER_KEYED_UINT_SCALAR);
+    }
+    case 11: { // test.string_list_metric
+      return Some(ScalarID::YET_ANOTHER_KEYED_BOOL_SCALAR);
+    }
+    case 12: { // test.string_metric
+      return Some(ScalarID::SOME_STRING_SCALAR);
+    }
+    case 14: { // test.timespan_metric
+      return Some(ScalarID::SOME_OTHER_UINT_SCALAR);
+    }
+    case 16: { // test.nested.datetime_metric
+      return Some(ScalarID::SOME_STILL_OTHER_STRING_SCALAR);
+    }
+    case 21: { // test.nested.quantity_metric
+      return Some(ScalarID::TELEMETRY_TEST_MIRROR_FOR_QUANTITY);
+    }
+    case 24: { // test.nested.uuid_metric
+      return Some(ScalarID::SOME_OTHER_STRING_SCALAR);
+    }
+    default: {
+      if (MOZ_UNLIKELY(aId & (1 << DYNAMIC_METRIC_BIT))) {
+        // Dynamic (runtime-registered) metric. Use its static (compiletime-
+        // registered) metric's telemetry_mirror mapping.
+        // ...if applicable.
+
+        // Only JS can use dynamic (runtime-registered) metric ids.
+        MOZ_ASSERT(NS_IsMainThread());
+
+        auto metricName = JOG::GetMetricName(aId);
+        // All of these should have names, but the storage only lasts until
+        // XPCOMWillShutdown, so it might return `Nothing()`.
+        if (metricName.isSome()) {
+          auto maybeMetric = MetricByNameLookup(metricName.ref());
+          if (maybeMetric.isSome()) {
+            uint32_t staticId = GLEAN_METRIC_ID(maybeMetric.value());
+            // Let's ensure we don't infinite loop, huh.
+            MOZ_ASSERT(!(staticId & (1 << DYNAMIC_METRIC_BIT)));
+            return ScalarIdForMetric(staticId);
+          }
+        }
+      }
+      return Nothing();
+    }
+  }
+}
+
+}  // namespace mozilla::glean
+
+#undef GLEAN_METRIC_ID
+#undef DYNAMIC_METRIC_BIT
+
+#endif  // mozilla_glean_ScalarGifftMaps_h
diff --git a/toolkit/components/glean/tests/pytest/jogfile_output b/toolkit/components/glean/tests/pytest/jogfile_output
new file mode 100644
index 0000000000..d75c08c8ba
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/jogfile_output
@@ -0,0 +1,344 @@
+{
+  "metrics": {
+    "test": [
+      [
+        "boolean",
+        "boolean_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ],
+      [
+        "counter",
+        "counter_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ],
+      [
+        "custom_distribution",
+        "custom_distribution_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "bucket_count": 100,
+          "histogram_type": "linear",
+          "range_max": 100,
+          "range_min": 0
+        }
+      ],
+      [
+        "labeled_boolean",
+        "labeled_boolean_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": null
+        }
+      ],
+      [
+        "labeled_boolean",
+        "labeled_boolean_metric_labels",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": [
+            "one_label",
+            "two_labels",
+            "three_labels",
+            "four_labels",
+            "five_labels",
+            "six_labels",
+            "seven_labels",
+            "eight_labels",
+            "nine_labels",
+            "ten_labels"
+          ]
+        }
+      ],
+      [
+        "labeled_counter",
+        "labeled_counter_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": null
+        }
+      ],
+      [
+        "labeled_counter",
+        "labeled_counter_metric_labels",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": [
+            "one_label",
+            "two_labels"
+          ]
+        }
+      ],
+      [
+        "labeled_string",
+        "labeled_string_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": null
+        }
+      ],
+      [
+        "labeled_string",
+        "labeled_string_metric_labels",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "ordered_labels": [
+            "one_label",
+            "two_labels"
+          ]
+        }
+      ],
+      [
+        "memory_distribution",
+        "memory_distribution_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "memory_unit": "kilobyte"
+        }
+      ],
+      [
+        "string_list",
+        "string_list_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ],
+      [
+        "string",
+        "string_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ],
+      [
+        "text",
+        "text_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ],
+      [
+        "timespan",
+        "timespan_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "time_unit": "millisecond"
+        }
+      ],
+      [
+        "timing_distribution",
+        "timing_distribution_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "time_unit": "nanosecond"
+        }
+      ]
+    ],
+    "test.nested": [
+      [
+        "datetime",
+        "datetime_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false,
+        {
+          "time_unit": "millisecond"
+        }
+      ],
+      [
+        "event",
+        "event_metric",
+        [
+          "events"
+        ],
+        "ping",
+        false,
+        {
+          "allowed_extra_keys": []
+        }
+      ],
+      [
+        "event",
+        "event_metric_with_extra",
+        [
+          "events"
+        ],
+        "ping",
+        false,
+        {
+          "allowed_extra_keys": [
+            "an_extra_key",
+            "another_extra_key"
+          ]
+        }
+      ],
+      [
+        "denominator",
+        "external_denominator",
+        [
+          "metrics"
+        ],
+        "ping",
+        false,
+        {
+          "numerators": [
+            [
+              "rate_with_external_denominator",
+              "test.nested",
+              [
+                "metrics"
+              ],
+              "ping",
+              false,
+              null
+            ]
+          ]
+        }
+      ],
+      [
+        "counter",
+        "optimizable_counter_metric",
+        [
+          "metrics"
+        ],
+        "ping",
+        false
+      ],
+      [
+        "quantity",
+        "quantity_metric",
+        [
+          "metrics"
+        ],
+        "ping",
+        false
+      ],
+      [
+        "rate",
+        "rate_metric",
+        [
+          "metrics"
+        ],
+        "ping",
+        false
+      ],
+      [
+        "rate",
+        "rate_with_external_denominator",
+        [
+          "metrics"
+        ],
+        "ping",
+        false
+      ],
+      [
+        "uuid",
+        "uuid_metric",
+        [
+          "metrics"
+        ],
+        "application",
+        false
+      ]
+    ]
+  },
+  "pings": [
+    [
+      "not-baseline",
+      true,
+      false,
+      true,
+      [
+        "background",
+        "dirty_startup",
+        "foreground"
+      ]
+    ],
+    [
+      "not-deletion-request",
+      true,
+      true,
+      true,
+      []
+    ],
+    [
+      "not-events",
+      true,
+      false,
+      true,
+      [
+        "background",
+        "max_capacity",
+        "startup"
+      ]
+    ],
+    [
+      "not-metrics",
+      true,
+      false,
+      true,
+      [
+        "overdue",
+        "reschedule",
+        "today",
+        "tomorrow",
+        "upgrade"
+      ]
+    ]
+  ]
+}
\ No newline at end of file
diff --git a/toolkit/components/glean/tests/pytest/metrics_expires_versions_test.yaml b/toolkit/components/glean/tests/pytest/metrics_expires_versions_test.yaml
new file mode 100644
index 0000000000..ea73a6465e
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_expires_versions_test.yaml
@@ -0,0 +1,84 @@
+# 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/.
+
+# This file is FOR TESTING PURPOSES ONLY.
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+
+test:
+  expired1:
+    type: boolean
+    expires: 41
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1664306
+    data_reviews:
+      - https://example.com
+    no_lint:
+      - EXPIRED
+
+  expired2:
+    type: labeled_boolean
+    expires: 42
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1664306
+    data_reviews:
+      - https://example.com
+    no_lint:
+      - EXPIRED
+
+  unexpired:
+    type: labeled_boolean
+    expires: 100
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1664306
+    data_reviews:
+      - https://example.com
+    labels:
+      - one_label
+      - two_labels
+
+  never:
+    type: string
+    expires: never
+    description: A never-expiring metric
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1664306
+    data_reviews:
+      - https://example.com
+
+  always:
+    type: string
+    expires: expired
+    description: An already-expired metric
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1664306
+    data_reviews:
+      - https://example.com
+    no_lint:
+      - EXPIRED
diff --git a/toolkit/components/glean/tests/pytest/metrics_test.yaml b/toolkit/components/glean/tests/pytest/metrics_test.yaml
new file mode 100644
index 0000000000..cbbb0220b5
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_test.yaml
@@ -0,0 +1,398 @@
+# 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/.
+
+# This file defines the metrics that are recorded by the Glean SDK. They are
+# automatically converted to platform-specific code at build time using the
+# `glean_parser` PyPI package.
+
+# This file is presently for Internal FOG Use Only.
+# You should not add metrics here until probably about January of 2021.
+# If you're looking for the metrics.yaml for Geckoveiw Streaming Telemetry,
+# you can find that one in toolkit/components/telemetry/geckoview/streaming.
+
+---
+$schema: moz://mozilla.org/schemas/glean/metrics/2-0-0
+
+test:
+  boolean_metric:
+    type: boolean
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_BOOL_SCALAR
+
+  labeled_boolean_metric:
+    type: labeled_boolean
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_KEYED_BOOL_SCALAR
+
+  labeled_boolean_metric_labels:
+    type: labeled_boolean
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    labels:
+      - one_label
+      - two_labels
+      - three_labels
+      - four_labels
+      - five_labels
+      - six_labels
+      - seven_labels
+      - eight_labels
+      - nine_labels
+      - ten_labels
+    telemetry_mirror: SOME_OTHER_KEYED_BOOL_SCALAR
+
+  counter_metric:
+    type: counter
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_UINT_SCALAR
+
+  labeled_counter_metric:
+    type: labeled_counter
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_KEYED_UINT_SCALAR
+
+  labeled_counter_metric_labels:
+    type: labeled_counter
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    labels:
+      - one_label
+      - two_labels
+    telemetry_mirror: SOME_OTHER_KEYED_UINT_SCALAR
+
+  string_metric:
+    type: string
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_STRING_SCALAR
+
+  labeled_string_metric:
+    type: labeled_string
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+
+  labeled_string_metric_labels:
+    type: labeled_string
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    labels:
+      - one_label
+      - two_labels
+
+  string_list_metric:
+    type: string_list
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: YET_ANOTHER_KEYED_BOOL_SCALAR
+
+  text_metric:
+    type: text
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1828528
+    data_reviews:
+      - https://example.com
+
+
+  timespan_metric:
+    type: timespan
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_OTHER_UINT_SCALAR
+
+  timing_distribution_metric:
+    type: timing_distribution
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_TIME_HISTOGRAM_MS
+
+  memory_distribution_metric:
+    type: memory_distribution
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    memory_unit: kilobyte
+    telemetry_mirror: SOME_MEM_HISTOGRAM_KB
+
+  custom_distribution_metric:
+    type: custom_distribution
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    range_min: 0
+    range_max: 100
+    bucket_count: 100
+    histogram_type: linear
+    telemetry_mirror: SOME_LINEAR_HISTOGRAM
+
+test.nested:
+  uuid_metric:
+    type: uuid
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_OTHER_STRING_SCALAR
+
+  datetime_metric:
+    type: datetime
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: application
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: SOME_STILL_OTHER_STRING_SCALAR
+
+  event_metric:
+    type: event
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: ping
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: EventMetric_EnumNames_AreStrange
+
+  event_metric_with_extra:
+    type: event
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: ping
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
+    extra_keys:
+      an_extra_key:
+        type: string
+        description: An extra key description
+      another_extra_key:
+        type: string
+        description: Another extra key description
+    telemetry_mirror: EventMetric_EnumName_WithExtra
+
+  quantity_metric:
+    type: quantity
+    unit: someunit
+    expires: never
+    description: |
+      A multi-line
+      description
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1704846/
+    data_reviews:
+      - https://example.com
+    telemetry_mirror: TELEMETRY_TEST_MIRROR_FOR_QUANTITY
+
+  rate_metric:
+    type: rate
+    expires: never
+    description: |
+      A multi-line
+      description
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1704846/
+    data_reviews:
+      - https://example.com
+
+  rate_with_external_denominator:
+    type: rate
+    denominator_metric: test.nested.external_denominator
+    expires: never
+    description: |
+      A multi-line
+      description
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1704846/
+    data_reviews:
+      - https://example.com
+
+  external_denominator:
+    type: counter
+    expires: never
+    description: |
+      A multi-line
+      description
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1704846/
+    data_reviews:
+      - https://example.com
+
+  optimizable_counter_metric:
+    type: counter
+    expires: never
+    description: |
+      A multi-line
+      description
+    lifetime: ping
+    notification_emails:
+      - glean-team@mozilla.com
+    bugs:
+      - https://bugzilla.mozilla.org/1635260/
+    data_reviews:
+      - https://example.com
diff --git a/toolkit/components/glean/tests/pytest/metrics_test_output b/toolkit/components/glean/tests/pytest/metrics_test_output
new file mode 100644
index 0000000000..76808cc984
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_test_output
@@ -0,0 +1,918 @@
+// -*- mode: Rust -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+pub enum DynamicLabel { }
+
+pub mod test {
+    use crate::private::*;
+    #[allow(unused_imports)] // CommonMetricData might be unused, let's avoid warnings
+    use glean::CommonMetricData;
+    #[allow(unused_imports)] // HistogramType might be unusued, let's avoid warnings
+    use glean::HistogramType;
+    use once_cell::sync::Lazy;
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.boolean_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static boolean_metric: Lazy<BooleanMetric> = Lazy::new(|| {
+        BooleanMetric::new(1.into(), CommonMetricData {
+            name: "boolean_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.counter_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static counter_metric: Lazy<CounterMetric> = Lazy::new(|| {
+        CounterMetric::new(2.into(), CommonMetricData {
+            name: "counter_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.custom_distribution_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static custom_distribution_metric: Lazy<CustomDistributionMetric> = Lazy::new(|| {
+        CustomDistributionMetric::new(3.into(), CommonMetricData {
+            name: "custom_distribution_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, 0, 100, 100, HistogramType::Linear)
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_boolean_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_boolean_metric: Lazy<LabeledMetric<LabeledBooleanMetric, super::DynamicLabel>> = Lazy::new(|| {
+        LabeledMetric::new(4.into(), CommonMetricData {
+            name: "labeled_boolean_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, None)
+    });
+
+    #[repr(u16)]
+    pub enum LabeledBooleanMetricLabelsLabel {
+        OneLabel = 0,
+        TwoLabels = 1,
+        ThreeLabels = 2,
+        FourLabels = 3,
+        FiveLabels = 4,
+        SixLabels = 5,
+        SevenLabels = 6,
+        EightLabels = 7,
+        NineLabels = 8,
+        TenLabels = 9,
+        __Other__,
+    }
+    impl From<u16> for LabeledBooleanMetricLabelsLabel {
+        fn from(v: u16) -> Self {
+            match v {
+                0 => Self::OneLabel,
+                1 => Self::TwoLabels,
+                2 => Self::ThreeLabels,
+                3 => Self::FourLabels,
+                4 => Self::FiveLabels,
+                5 => Self::SixLabels,
+                6 => Self::SevenLabels,
+                7 => Self::EightLabels,
+                8 => Self::NineLabels,
+                9 => Self::TenLabels,
+                _ => Self::__Other__,
+            }
+        }
+    }
+    impl Into<&'static str> for LabeledBooleanMetricLabelsLabel {
+        fn into(self) -> &'static str {
+            match self {
+                Self::OneLabel => "one_label",
+                Self::TwoLabels => "two_labels",
+                Self::ThreeLabels => "three_labels",
+                Self::FourLabels => "four_labels",
+                Self::FiveLabels => "five_labels",
+                Self::SixLabels => "six_labels",
+                Self::SevenLabels => "seven_labels",
+                Self::EightLabels => "eight_labels",
+                Self::NineLabels => "nine_labels",
+                Self::TenLabels => "ten_labels",
+                Self::__Other__ => "__other__",
+            }
+        }
+    }
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_boolean_metric_labels
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_boolean_metric_labels: Lazy<LabeledMetric<LabeledBooleanMetric, LabeledBooleanMetricLabelsLabel>> = Lazy::new(|| {
+        LabeledMetric::new(5.into(), CommonMetricData {
+            name: "labeled_boolean_metric_labels".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, Some(vec![::std::borrow::Cow::from("eight_labels"), ::std::borrow::Cow::from("five_labels"), ::std::borrow::Cow::from("four_labels"), ::std::borrow::Cow::from("nine_labels"), ::std::borrow::Cow::from("one_label"), ::std::borrow::Cow::from("seven_labels"), ::std::borrow::Cow::from("six_labels"), ::std::borrow::Cow::from("ten_labels"), ::std::borrow::Cow::from("three_labels"), ::std::borrow::Cow::from("two_labels")]))
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_counter_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_counter_metric: Lazy<LabeledMetric<LabeledCounterMetric, super::DynamicLabel>> = Lazy::new(|| {
+        LabeledMetric::new(6.into(), CommonMetricData {
+            name: "labeled_counter_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, None)
+    });
+
+    #[repr(u16)]
+    pub enum LabeledCounterMetricLabelsLabel {
+        OneLabel = 0,
+        TwoLabels = 1,
+        __Other__,
+    }
+    impl From<u16> for LabeledCounterMetricLabelsLabel {
+        fn from(v: u16) -> Self {
+            match v {
+                0 => Self::OneLabel,
+                1 => Self::TwoLabels,
+                _ => Self::__Other__,
+            }
+        }
+    }
+    impl Into<&'static str> for LabeledCounterMetricLabelsLabel {
+        fn into(self) -> &'static str {
+            match self {
+                Self::OneLabel => "one_label",
+                Self::TwoLabels => "two_labels",
+                Self::__Other__ => "__other__",
+            }
+        }
+    }
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_counter_metric_labels
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_counter_metric_labels: Lazy<LabeledMetric<LabeledCounterMetric, LabeledCounterMetricLabelsLabel>> = Lazy::new(|| {
+        LabeledMetric::new(7.into(), CommonMetricData {
+            name: "labeled_counter_metric_labels".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, Some(vec![::std::borrow::Cow::from("one_label"), ::std::borrow::Cow::from("two_labels")]))
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_string_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_string_metric: Lazy<LabeledMetric<LabeledStringMetric, super::DynamicLabel>> = Lazy::new(|| {
+        LabeledMetric::new(8.into(), CommonMetricData {
+            name: "labeled_string_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, None)
+    });
+
+    #[repr(u16)]
+    pub enum LabeledStringMetricLabelsLabel {
+        OneLabel = 0,
+        TwoLabels = 1,
+        __Other__,
+    }
+    impl From<u16> for LabeledStringMetricLabelsLabel {
+        fn from(v: u16) -> Self {
+            match v {
+                0 => Self::OneLabel,
+                1 => Self::TwoLabels,
+                _ => Self::__Other__,
+            }
+        }
+    }
+    impl Into<&'static str> for LabeledStringMetricLabelsLabel {
+        fn into(self) -> &'static str {
+            match self {
+                Self::OneLabel => "one_label",
+                Self::TwoLabels => "two_labels",
+                Self::__Other__ => "__other__",
+            }
+        }
+    }
+    #[allow(non_upper_case_globals)]
+    /// generated from test.labeled_string_metric_labels
+    ///
+    /// A multi-line
+    /// description
+    pub static labeled_string_metric_labels: Lazy<LabeledMetric<LabeledStringMetric, LabeledStringMetricLabelsLabel>> = Lazy::new(|| {
+        LabeledMetric::new(9.into(), CommonMetricData {
+            name: "labeled_string_metric_labels".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, Some(vec![::std::borrow::Cow::from("one_label"), ::std::borrow::Cow::from("two_labels")]))
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.memory_distribution_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static memory_distribution_metric: Lazy<MemoryDistributionMetric> = Lazy::new(|| {
+        MemoryDistributionMetric::new(10.into(), CommonMetricData {
+            name: "memory_distribution_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, MemoryUnit::Kilobyte)
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.string_list_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static string_list_metric: Lazy<StringListMetric> = Lazy::new(|| {
+        StringListMetric::new(11.into(), CommonMetricData {
+            name: "string_list_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.string_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static string_metric: Lazy<StringMetric> = Lazy::new(|| {
+        StringMetric::new(12.into(), CommonMetricData {
+            name: "string_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.text_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static text_metric: Lazy<TextMetric> = Lazy::new(|| {
+        TextMetric::new(13.into(), CommonMetricData {
+            name: "text_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.timespan_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static timespan_metric: Lazy<TimespanMetric> = Lazy::new(|| {
+        TimespanMetric::new(14.into(), CommonMetricData {
+            name: "timespan_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, TimeUnit::Millisecond)
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.timing_distribution_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static timing_distribution_metric: Lazy<TimingDistributionMetric> = Lazy::new(|| {
+        TimingDistributionMetric::new(15.into(), CommonMetricData {
+            name: "timing_distribution_metric".into(),
+            category: "test".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, TimeUnit::Nanosecond)
+    });
+
+}
+pub mod test_nested {
+    use crate::private::*;
+    #[allow(unused_imports)] // CommonMetricData might be unused, let's avoid warnings
+    use glean::CommonMetricData;
+    #[allow(unused_imports)] // HistogramType might be unusued, let's avoid warnings
+    use glean::HistogramType;
+    use once_cell::sync::Lazy;
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.datetime_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static datetime_metric: Lazy<DatetimeMetric> = Lazy::new(|| {
+        DatetimeMetric::new(16.into(), CommonMetricData {
+            name: "datetime_metric".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        }, TimeUnit::Millisecond)
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.event_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static event_metric: Lazy<EventMetric<NoExtraKeys>> = Lazy::new(|| {
+        EventMetric::new(17.into(), CommonMetricData {
+            name: "event_metric".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["events".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[derive(Default, Debug, Clone, Hash, Eq, PartialEq)]
+    pub struct EventMetricWithExtraExtra {
+        pub an_extra_key: Option<String>,
+        pub another_extra_key: Option<String>,
+    }
+
+    impl ExtraKeys for EventMetricWithExtraExtra {
+        const ALLOWED_KEYS: &'static [&'static str] = &["an_extra_key", "another_extra_key"];
+
+        fn into_ffi_extra(self) -> ::std::collections::HashMap<String, String> {
+          let mut map = ::std::collections::HashMap::new();
+          self.an_extra_key.and_then(|val| map.insert("an_extra_key".into(), val.to_string()));
+          self.another_extra_key.and_then(|val| map.insert("another_extra_key".into(), val.to_string()));
+          map
+        }
+    }
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.event_metric_with_extra
+    ///
+    /// A multi-line
+    /// description
+    pub static event_metric_with_extra: Lazy<EventMetric<EventMetricWithExtraExtra>> = Lazy::new(|| {
+        EventMetric::new(18.into(), CommonMetricData {
+            name: "event_metric_with_extra".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["events".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.external_denominator
+    ///
+    /// A multi-line
+    /// description
+    pub static external_denominator: Lazy<DenominatorMetric> = Lazy::new(|| {
+        DenominatorMetric::new(19.into(), CommonMetricData {
+            name: "external_denominator".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        }, vec![CommonMetricData {name: "rate_with_external_denominator".into(), category: "test.nested".into(), send_in_pings: vec!["metrics".into()], lifetime: Lifetime::Ping, disabled: false,  ..Default::default()}])
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.optimizable_counter_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static optimizable_counter_metric: Lazy<CounterMetric> = Lazy::new(|| {
+        CounterMetric::codegen_new(
+            20,
+            "test.nested",
+            "optimizable_counter_metric",
+            "metrics"
+        )
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.quantity_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static quantity_metric: Lazy<QuantityMetric> = Lazy::new(|| {
+        QuantityMetric::new(21.into(), CommonMetricData {
+            name: "quantity_metric".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.rate_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static rate_metric: Lazy<RateMetric> = Lazy::new(|| {
+        RateMetric::new(22.into(), CommonMetricData {
+            name: "rate_metric".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.rate_with_external_denominator
+    ///
+    /// A multi-line
+    /// description
+    pub static rate_with_external_denominator: Lazy<NumeratorMetric> = Lazy::new(|| {
+        NumeratorMetric::new(23.into(), CommonMetricData {
+            name: "rate_with_external_denominator".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Ping,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+    #[allow(non_upper_case_globals)]
+    /// generated from test.nested.uuid_metric
+    ///
+    /// A multi-line
+    /// description
+    pub static uuid_metric: Lazy<UuidMetric> = Lazy::new(|| {
+        UuidMetric::new(24.into(), CommonMetricData {
+            name: "uuid_metric".into(),
+            category: "test.nested".into(),
+            send_in_pings: vec!["metrics".into()],
+            lifetime: Lifetime::Application,
+            disabled: false,
+            ..Default::default()
+        })
+    });
+
+}
+
+#[allow(dead_code)]
+pub(crate) mod __glean_metric_maps {
+    use std::collections::HashMap;
+
+    use crate::metrics::extra_keys_len;
+    use crate::private::*;
+    use once_cell::sync::Lazy;
+
+    pub static BOOLEAN_MAP: Lazy<HashMap<MetricId, &Lazy<BooleanMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(1.into(), &super::test::boolean_metric);
+        map
+    });
+
+    pub static COUNTER_MAP: Lazy<HashMap<MetricId, &Lazy<CounterMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(2);
+        map.insert(2.into(), &super::test::counter_metric);
+        map.insert(20.into(), &super::test_nested::optimizable_counter_metric);
+        map
+    });
+
+    pub static CUSTOM_DISTRIBUTION_MAP: Lazy<HashMap<MetricId, &Lazy<CustomDistributionMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(3.into(), &super::test::custom_distribution_metric);
+        map
+    });
+
+    pub static MEMORY_DISTRIBUTION_MAP: Lazy<HashMap<MetricId, &Lazy<MemoryDistributionMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(10.into(), &super::test::memory_distribution_metric);
+        map
+    });
+
+    pub static STRING_LIST_MAP: Lazy<HashMap<MetricId, &Lazy<StringListMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(11.into(), &super::test::string_list_metric);
+        map
+    });
+
+    pub static STRING_MAP: Lazy<HashMap<MetricId, &Lazy<StringMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(12.into(), &super::test::string_metric);
+        map
+    });
+
+    pub static TEXT_MAP: Lazy<HashMap<MetricId, &Lazy<TextMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(13.into(), &super::test::text_metric);
+        map
+    });
+
+    pub static TIMESPAN_MAP: Lazy<HashMap<MetricId, &Lazy<TimespanMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(14.into(), &super::test::timespan_metric);
+        map
+    });
+
+    pub static TIMING_DISTRIBUTION_MAP: Lazy<HashMap<MetricId, &Lazy<TimingDistributionMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(15.into(), &super::test::timing_distribution_metric);
+        map
+    });
+
+    pub static DATETIME_MAP: Lazy<HashMap<MetricId, &Lazy<DatetimeMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(16.into(), &super::test_nested::datetime_metric);
+        map
+    });
+
+    pub static DENOMINATOR_MAP: Lazy<HashMap<MetricId, &Lazy<DenominatorMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(19.into(), &super::test_nested::external_denominator);
+        map
+    });
+
+    pub static QUANTITY_MAP: Lazy<HashMap<MetricId, &Lazy<QuantityMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(21.into(), &super::test_nested::quantity_metric);
+        map
+    });
+
+    pub static RATE_MAP: Lazy<HashMap<MetricId, &Lazy<RateMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(22.into(), &super::test_nested::rate_metric);
+        map
+    });
+
+    pub static NUMERATOR_MAP: Lazy<HashMap<MetricId, &Lazy<NumeratorMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(23.into(), &super::test_nested::rate_with_external_denominator);
+        map
+    });
+
+    pub static UUID_MAP: Lazy<HashMap<MetricId, &Lazy<UuidMetric>>> = Lazy::new(|| {
+        let mut map = HashMap::with_capacity(1);
+        map.insert(24.into(), &super::test_nested::uuid_metric);
+        map
+    });
+
+
+    /// Wrapper to record an event based on its metric ID.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `extra`     - An map of (extra key id, string) pairs.
+    ///                 The map will be decoded into the appropriate `ExtraKeys` type.
+    /// # Returns
+    ///
+    /// Returns `Ok(())` if the event was found and `record` was called with the given `extra`,
+    /// or an `EventRecordingError::InvalidId` if no event by that ID exists
+    /// or an `EventRecordingError::InvalidExtraKey` if the `extra` map could not be deserialized.
+    pub(crate) fn record_event_by_id(metric_id: u32, extra: HashMap<String, String>) -> Result<(), EventRecordingError> {
+        match metric_id {
+          17 => {
+              assert!(
+                  extra_keys_len(&super::test_nested::event_metric) != 0 || extra.is_empty(),
+                  "No extra keys allowed, but some were passed"
+              );
+
+              super::test_nested::event_metric.record_raw(extra);
+              Ok(())
+          }
+          18 => {
+              assert!(
+                  extra_keys_len(&super::test_nested::event_metric_with_extra) != 0 || extra.is_empty(),
+                  "No extra keys allowed, but some were passed"
+              );
+
+              super::test_nested::event_metric_with_extra.record_raw(extra);
+              Ok(())
+          }
+           _ => Err(EventRecordingError::InvalidId),
+        }
+    }
+
+    /// Wrapper to record an event based on its metric ID, with a provided timestamp.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `timestamp` - The time at which this event was recorded.
+    /// * `extra`     - An map of (extra key id, string) pairs.
+    ///                 The map will be decoded into the appropriate `ExtraKeys` type.
+    /// # Returns
+    ///
+    /// Returns `Ok(())` if the event was found and `record` was called with the given `extra`,
+    /// or an `EventRecordingError::InvalidId` if no event by that ID exists
+    /// or an `EventRecordingError::InvalidExtraKey` if the event doesn't take extra pairs,
+    /// but some are passed in.
+    pub(crate) fn record_event_by_id_with_time(metric_id: MetricId, timestamp: u64, extra: HashMap<String, String>) -> Result<(), EventRecordingError> {
+        match metric_id {
+          MetricId(17) => {
+              if extra_keys_len(&super::test_nested::event_metric) == 0 && !extra.is_empty() {
+                return Err(EventRecordingError::InvalidExtraKey);
+              }
+
+              super::test_nested::event_metric.record_with_time(timestamp, extra);
+              Ok(())
+          }
+          MetricId(18) => {
+              if extra_keys_len(&super::test_nested::event_metric_with_extra) == 0 && !extra.is_empty() {
+                return Err(EventRecordingError::InvalidExtraKey);
+              }
+
+              super::test_nested::event_metric_with_extra.record_with_time(timestamp, extra);
+              Ok(())
+          }
+           _ => Err(EventRecordingError::InvalidId),
+        }
+    }
+
+    /// Wrapper to get the currently stored events for event metric.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `ping_name` - (Optional) The ping name to look into.
+    ///                 Defaults to the first value in `send_in_pings`.
+    ///
+    /// # Returns
+    ///
+    /// Returns the recorded events or `None` if nothing stored.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no event by the given metric ID could be found.
+    pub(crate) fn event_test_get_value_wrapper(metric_id: u32, ping_name: Option<String>) -> Option<Vec<RecordedEvent>> {
+        match metric_id {
+           17 => super::test_nested::event_metric.test_get_value(ping_name.as_deref()),
+           18 => super::test_nested::event_metric_with_extra.test_get_value(ping_name.as_deref()),
+           _ => panic!("No event for metric id {}", metric_id),
+        }
+    }
+
+    /// Check the provided event for errors.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `ping_name` - (Optional) The ping name to look into.
+    ///                 Defaults to the first value in `send_in_pings`.
+    ///
+    /// # Returns
+    ///
+    /// Returns a string for the recorded error or `None`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no event by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn event_test_get_error(metric_id: u32) -> Option<String> {
+        #[cfg(feature = "with_gecko")]
+        match metric_id {
+           17 => test_get_errors!(super::test_nested::event_metric),
+           18 => test_get_errors!(super::test_nested::event_metric_with_extra),
+           _ => panic!("No event for metric id {}", metric_id),
+        }
+
+        #[cfg(not(feature = "with_gecko"))]
+        {
+            return None;
+        }
+    }
+
+    /// Gets the submetric from the specified labeled_boolean metric.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label` - The label identifying the boolean submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the boolean submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_boolean by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_boolean_get(metric_id: u32, label: &str) -> LabeledBooleanMetric {
+        match metric_id {
+            4 => super::test::labeled_boolean_metric.get(label),
+            5 => super::test::labeled_boolean_metric_labels.get(label),
+            _ => panic!("No labeled_boolean for metric id {}", metric_id),
+        }
+    }
+
+    /// Gets the submetric from the specified labeled_boolean metric, by enum.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label_enum` - The label enum identifying the boolean submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the boolean submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_boolean by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_boolean_enum_get(metric_id: u32, label_enum: u16) -> LabeledBooleanMetric {
+        match metric_id {
+            5 => super::test::labeled_boolean_metric_labels.get(labeled_enum_to_str(metric_id, label_enum)),
+            _ => panic!("No labeled_boolean for metric id {}", metric_id),
+        }
+    }
+    /// Gets the submetric from the specified labeled_counter metric.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label` - The label identifying the counter submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the counter submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_counter by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_counter_get(metric_id: u32, label: &str) -> LabeledCounterMetric {
+        match metric_id {
+            6 => super::test::labeled_counter_metric.get(label),
+            7 => super::test::labeled_counter_metric_labels.get(label),
+            _ => panic!("No labeled_counter for metric id {}", metric_id),
+        }
+    }
+
+    /// Gets the submetric from the specified labeled_counter metric, by enum.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label_enum` - The label enum identifying the counter submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the counter submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_counter by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_counter_enum_get(metric_id: u32, label_enum: u16) -> LabeledCounterMetric {
+        match metric_id {
+            7 => super::test::labeled_counter_metric_labels.get(labeled_enum_to_str(metric_id, label_enum)),
+            _ => panic!("No labeled_counter for metric id {}", metric_id),
+        }
+    }
+    /// Gets the submetric from the specified labeled_string metric.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label` - The label identifying the string submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the string submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_string by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_string_get(metric_id: u32, label: &str) -> LabeledStringMetric {
+        match metric_id {
+            8 => super::test::labeled_string_metric.get(label),
+            9 => super::test::labeled_string_metric_labels.get(label),
+            _ => panic!("No labeled_string for metric id {}", metric_id),
+        }
+    }
+
+    /// Gets the submetric from the specified labeled_string metric, by enum.
+    ///
+    /// # Arguments
+    ///
+    /// * `metric_id` - The metric's ID to look up
+    /// * `label_enum` - The label enum identifying the string submetric.
+    ///
+    /// # Returns
+    ///
+    /// Returns the string submetric.
+    ///
+    /// # Panics
+    ///
+    /// Panics if no labeled_string by the given metric ID could be found.
+    #[allow(unused_variables)]
+    pub(crate) fn labeled_string_enum_get(metric_id: u32, label_enum: u16) -> LabeledStringMetric {
+        match metric_id {
+            9 => super::test::labeled_string_metric_labels.get(labeled_enum_to_str(metric_id, label_enum)),
+            _ => panic!("No labeled_string for metric id {}", metric_id),
+        }
+    }
+
+    pub(crate) fn labeled_enum_to_str(metric_id: u32, label: u16) -> &'static str {
+        match metric_id {
+            5 => super::test::LabeledBooleanMetricLabelsLabel::from(label).into(),
+            7 => super::test::LabeledCounterMetricLabelsLabel::from(label).into(),
+            9 => super::test::LabeledStringMetricLabelsLabel::from(label).into(),
+            _ => panic!("Can't turn label enum to string for metric {} which isn't a labeled metric with static labels", metric_id),
+        }
+    }
+
+    pub(crate) mod submetric_maps {
+        use std::sync::{
+          atomic::AtomicU32,
+          RwLock,
+        };
+        use super::*;
+
+        pub(crate) const SUBMETRIC_BIT: u32 = 25;
+        pub(crate) static NEXT_LABELED_SUBMETRIC_ID: AtomicU32 = AtomicU32::new((1 << SUBMETRIC_BIT) + 1);
+        pub(crate) static LABELED_METRICS_TO_IDS: Lazy<RwLock<HashMap<(u32, String), u32>>> = Lazy::new(||
+            RwLock::new(HashMap::new())
+        );
+        pub(crate) static LABELED_ENUMS_TO_IDS: Lazy<RwLock<HashMap<(u32, u16), u32>>> = Lazy::new(||
+            RwLock::new(HashMap::new())
+        );
+
+        pub static BOOLEAN_MAP: Lazy<RwLock<HashMap<MetricId, LabeledBooleanMetric>>> = Lazy::new(||
+            RwLock::new(HashMap::new())
+        );
+        pub static COUNTER_MAP: Lazy<RwLock<HashMap<MetricId, LabeledCounterMetric>>> = Lazy::new(||
+            RwLock::new(HashMap::new())
+        );
+        pub static STRING_MAP: Lazy<RwLock<HashMap<MetricId, LabeledStringMetric>>> = Lazy::new(||
+            RwLock::new(HashMap::new())
+        );
+    }
+}
+
diff --git a/toolkit/components/glean/tests/pytest/metrics_test_output_cpp b/toolkit/components/glean/tests/pytest/metrics_test_output_cpp
new file mode 100644
index 0000000000..5b9c7bfae4
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_test_output_cpp
@@ -0,0 +1,287 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#ifndef mozilla_Metrics_h
+#define mozilla_Metrics_h
+
+#include "mozilla/glean/bindings/MetricTypes.h"
+#include "mozilla/Maybe.h"
+#include "nsTArray.h"
+#include "nsPrintfCString.h"
+
+#include <tuple>
+
+namespace mozilla::glean {
+struct NoExtraKeys;
+enum class DynamicLabel: uint16_t { };
+
+namespace test {
+  /**
+   * generated from test.boolean_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::BooleanMetric boolean_metric(1);
+
+  /**
+   * generated from test.counter_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::CounterMetric counter_metric(2);
+
+  /**
+   * generated from test.custom_distribution_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::CustomDistributionMetric custom_distribution_metric(3);
+
+  /**
+   * generated from test.labeled_boolean_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::BooleanMetric, DynamicLabel> labeled_boolean_metric(4);
+
+  /**
+   * generated from test.labeled_boolean_metric_labels
+   */
+  enum class LabeledBooleanMetricLabelsLabel: uint16_t {
+      eOneLabel = 0,
+      eTwoLabels = 1,
+      eThreeLabels = 2,
+      eFourLabels = 3,
+      eFiveLabels = 4,
+      eSixLabels = 5,
+      eSevenLabels = 6,
+      eEightLabels = 7,
+      eNineLabels = 8,
+      eTenLabels = 9,
+      e__Other__,
+    };
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::BooleanMetric, LabeledBooleanMetricLabelsLabel> labeled_boolean_metric_labels(5);
+
+  /**
+   * generated from test.labeled_counter_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::CounterMetric, DynamicLabel> labeled_counter_metric(6);
+
+  /**
+   * generated from test.labeled_counter_metric_labels
+   */
+  enum class LabeledCounterMetricLabelsLabel: uint16_t {
+      eOneLabel = 0,
+      eTwoLabels = 1,
+      e__Other__,
+    };
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::CounterMetric, LabeledCounterMetricLabelsLabel> labeled_counter_metric_labels(7);
+
+  /**
+   * generated from test.labeled_string_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::StringMetric, DynamicLabel> labeled_string_metric(8);
+
+  /**
+   * generated from test.labeled_string_metric_labels
+   */
+  enum class LabeledStringMetricLabelsLabel: uint16_t {
+      eOneLabel = 0,
+      eTwoLabels = 1,
+      e__Other__,
+    };
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::Labeled<impl::StringMetric, LabeledStringMetricLabelsLabel> labeled_string_metric_labels(9);
+
+  /**
+   * generated from test.memory_distribution_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::MemoryDistributionMetric memory_distribution_metric(10);
+
+  /**
+   * generated from test.string_list_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::StringListMetric string_list_metric(11);
+
+  /**
+   * generated from test.string_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::StringMetric string_metric(12);
+
+  /**
+   * generated from test.text_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::TextMetric text_metric(13);
+
+  /**
+   * generated from test.timespan_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::TimespanMetric timespan_metric(14);
+
+  /**
+   * generated from test.timing_distribution_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::TimingDistributionMetric timing_distribution_metric(15);
+
+}
+namespace test_nested {
+  /**
+   * generated from test.nested.datetime_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::DatetimeMetric datetime_metric(16);
+
+  /**
+   * generated from test.nested.event_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::EventMetric<NoExtraKeys> event_metric(17);
+
+  /**
+   * generated from test.nested.event_metric_with_extra
+   */
+    struct EventMetricWithExtraExtra {
+      mozilla::Maybe<nsCString> anExtraKey;
+      mozilla::Maybe<nsCString> anotherExtraKey;
+
+      std::tuple<nsTArray<nsCString>, nsTArray<nsCString>> ToFfiExtra() const {
+        nsTArray<nsCString> extraKeys;
+        nsTArray<nsCString> extraValues;
+        if (anExtraKey) {
+          extraKeys.AppendElement()->AssignASCII("an_extra_key");
+          extraValues.EmplaceBack(anExtraKey.value());
+        }
+        if (anotherExtraKey) {
+          extraKeys.AppendElement()->AssignASCII("another_extra_key");
+          extraValues.EmplaceBack(anotherExtraKey.value());
+        }
+        return std::make_tuple(std::move(extraKeys), std::move(extraValues));
+      }
+    };
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::EventMetric<EventMetricWithExtraExtra> event_metric_with_extra(18);
+
+  /**
+   * generated from test.nested.external_denominator
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::DenominatorMetric external_denominator(19);
+
+  /**
+   * generated from test.nested.optimizable_counter_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::CounterMetric optimizable_counter_metric(20);
+
+  /**
+   * generated from test.nested.quantity_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::QuantityMetric quantity_metric(21);
+
+  /**
+   * generated from test.nested.rate_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::RateMetric rate_metric(22);
+
+  /**
+   * generated from test.nested.rate_with_external_denominator
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::NumeratorMetric rate_with_external_denominator(23);
+
+  /**
+   * generated from test.nested.uuid_metric
+   */
+  /**
+   * A multi-line
+     * description
+   */
+  constexpr impl::UuidMetric uuid_metric(24);
+
+}
+
+} // namespace mozilla::glean
+
+#endif // mozilla_Metrics_h
diff --git a/toolkit/components/glean/tests/pytest/metrics_test_output_js_cpp b/toolkit/components/glean/tests/pytest/metrics_test_output_js_cpp
new file mode 100644
index 0000000000..ba4619bb57
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_test_output_js_cpp
@@ -0,0 +1,473 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#include "mozilla/glean/bindings/GleanJSMetricsLookup.h"
+
+#include "mozilla/PerfectHash.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/glean/bindings/MetricTypes.h"
+#include "mozilla/glean/fog_ffi_generated.h"
+#include "nsString.h"
+
+#define GLEAN_INDEX_BITS (32)
+#define GLEAN_TYPE_BITS (5)
+#define GLEAN_ID_BITS (27)
+#define GLEAN_TYPE_ID(id) ((id) >> GLEAN_ID_BITS)
+#define GLEAN_METRIC_ID(id) ((id) & ((1ULL << GLEAN_ID_BITS) - 1))
+#define GLEAN_OFFSET(entry) (entry & ((1ULL << GLEAN_INDEX_BITS) - 1))
+
+namespace mozilla::glean {
+
+// The category lookup table's entry type
+using category_entry_t = uint32_t;
+// The metric lookup table's entry type
+// This is a bitpacked type with 32 bits available to index into
+// the string table, 5 bits available to signify the metric type,
+// and the remaining 27 bits devoted to 2 "signal"
+// bits to signify important characteristics (metric's a labeled metric's
+// submetric, metric's been registered at runtime) and 25 bits
+// for built-in metric ids.
+// Gives room for 33554432 of each combination of
+// characteristics (which hopefully will prove to be enough).
+using metric_entry_t = uint64_t;
+
+static_assert(GLEAN_INDEX_BITS + GLEAN_TYPE_BITS + GLEAN_ID_BITS == sizeof(metric_entry_t) * 8, "Index, Type, and ID bits need to fit into a metric_entry_t");
+static_assert(GLEAN_TYPE_BITS + GLEAN_ID_BITS <= sizeof(uint32_t) * 8, "Metric Types and IDs need to fit into at most 32 bits");
+static_assert(2 < UINT32_MAX, "Too many metric categories generated.");
+static_assert(24 < 33554432, "Too many metrics generated. Need room for 2 signal bits.");
+static_assert(19 < 32, "Too many different metric types.");
+
+already_AddRefed<GleanMetric> NewMetricFromId(uint32_t id, nsISupports* aParent) {
+  uint32_t typeId = GLEAN_TYPE_ID(id);
+  uint32_t metricId = GLEAN_METRIC_ID(id);
+
+  switch (typeId) {
+    case 1: /* boolean */
+    {
+      return MakeAndAddRef<GleanBoolean>(metricId, aParent);
+    }
+    case 2: /* counter */
+    {
+      return MakeAndAddRef<GleanCounter>(metricId, aParent);
+    }
+    case 3: /* custom_distribution */
+    {
+      return MakeAndAddRef<GleanCustomDistribution>(metricId, aParent);
+    }
+    case 4: /* labeled_boolean */
+    {
+      return MakeAndAddRef<GleanLabeled>(metricId, 4, aParent);
+    }
+    case 5: /* labeled_counter */
+    {
+      return MakeAndAddRef<GleanLabeled>(metricId, 5, aParent);
+    }
+    case 6: /* labeled_string */
+    {
+      return MakeAndAddRef<GleanLabeled>(metricId, 6, aParent);
+    }
+    case 7: /* memory_distribution */
+    {
+      return MakeAndAddRef<GleanMemoryDistribution>(metricId, aParent);
+    }
+    case 8: /* string_list */
+    {
+      return MakeAndAddRef<GleanStringList>(metricId, aParent);
+    }
+    case 9: /* string */
+    {
+      return MakeAndAddRef<GleanString>(metricId, aParent);
+    }
+    case 10: /* text */
+    {
+      return MakeAndAddRef<GleanText>(metricId, aParent);
+    }
+    case 11: /* timespan */
+    {
+      return MakeAndAddRef<GleanTimespan>(metricId, aParent);
+    }
+    case 12: /* timing_distribution */
+    {
+      return MakeAndAddRef<GleanTimingDistribution>(metricId, aParent);
+    }
+    case 13: /* datetime */
+    {
+      return MakeAndAddRef<GleanDatetime>(metricId, aParent);
+    }
+    case 14: /* event */
+    {
+      return MakeAndAddRef<GleanEvent>(metricId, aParent);
+    }
+    case 15: /* denominator */
+    {
+      return MakeAndAddRef<GleanDenominator>(metricId, aParent);
+    }
+    case 16: /* quantity */
+    {
+      return MakeAndAddRef<GleanQuantity>(metricId, aParent);
+    }
+    case 17: /* rate */
+    {
+      return MakeAndAddRef<GleanRate>(metricId, aParent);
+    }
+    case 18: /* numerator */
+    {
+      return MakeAndAddRef<GleanNumerator>(metricId, aParent);
+    }
+    case 19: /* uuid */
+    {
+      return MakeAndAddRef<GleanUuid>(metricId, aParent);
+    }
+    default:
+    MOZ_ASSERT_UNREACHABLE("Invalid type ID reached when trying to instantiate a new metric");
+    return nullptr;
+  }
+}
+
+/**
+ * Create a submetric instance for a labeled metric of the provided type and id for the given label.
+ * Assigns or retrieves an id for the submetric from the SDK.
+ *
+ * @param aParentTypeId - The type of the parent labeled metric identified as a number generated during codegen.
+ *                        Only used to identify which X of LabeledX you are so that X can be created here.
+ * @param aParentMetricId - The metric id for the parent labeled metric.
+ * @param aLabel - The label for the submetric. Might not adhere to the SDK label format.
+ * @param aSubmetricId - an outparam which is assigned the submetric's SDK-generated submetric id.
+ *                       Used only by GIFFT.
+ */
+already_AddRefed<GleanMetric> NewSubMetricFromIds(uint32_t aParentTypeId,
+                                           uint32_t aParentMetricId,
+                                           const nsACString& aLabel,
+                                           uint32_t* aSubmetricId,
+                                           nsISupports* aParent) {
+  switch (aParentTypeId) {
+    case 4: { /* labeled_boolean */
+      auto id = impl::fog_labeled_boolean_get(aParentMetricId, &aLabel);
+      *aSubmetricId = id;
+      return MakeAndAddRef<GleanBoolean>(id, aParent);
+    }
+    case 5: { /* labeled_counter */
+      auto id = impl::fog_labeled_counter_get(aParentMetricId, &aLabel);
+      *aSubmetricId = id;
+      return MakeAndAddRef<GleanCounter>(id, aParent);
+    }
+    case 6: { /* labeled_string */
+      auto id = impl::fog_labeled_string_get(aParentMetricId, &aLabel);
+      *aSubmetricId = id;
+      return MakeAndAddRef<GleanString>(id, aParent);
+    }
+    default: {
+      MOZ_ASSERT_UNREACHABLE("Invalid type ID for submetric.");
+      return nullptr;
+    }
+  }
+}
+
+static Maybe<uint32_t> category_result_check(const nsACString& aKey, category_entry_t entry);
+static Maybe<uint32_t> metric_result_check(const nsACString& aKey, metric_entry_t entry);
+
+#if defined(_MSC_VER) && !defined(__clang__)
+const char gCategoryStringTable[] = {
+#else
+constexpr char gCategoryStringTable[] = {
+#endif
+  /*     0 - "test" */ 't', 'e', 's', 't', '\0',
+  /*     5 - "testNested" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '\0',
+};
+
+
+static_assert(sizeof(gCategoryStringTable) < UINT32_MAX, "Category string table is too large.");
+
+const category_entry_t sCategoryByNameLookupEntries[] = {
+  5ul,
+  0ul
+};
+
+
+
+Maybe<uint32_t>
+CategoryByNameLookup(const nsACString& aKey)
+{
+  static const uint8_t BASES[] = {
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+  };
+  
+
+  const char* bytes = aKey.BeginReading();
+  size_t length = aKey.Length();
+  auto& entry = mozilla::perfecthash::Lookup(bytes, length, BASES,
+                                             sCategoryByNameLookupEntries);
+  return category_result_check(aKey, entry);
+}
+
+
+#if defined(_MSC_VER) && !defined(__clang__)
+const char gMetricStringTable[] = {
+#else
+constexpr char gMetricStringTable[] = {
+#endif
+  /*     0 - "test.booleanMetric" */ 't', 'e', 's', 't', '.', 'b', 'o', 'o', 'l', 'e', 'a', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*    19 - "test.counterMetric" */ 't', 'e', 's', 't', '.', 'c', 'o', 'u', 'n', 't', 'e', 'r', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*    38 - "test.customDistributionMetric" */ 't', 'e', 's', 't', '.', 'c', 'u', 's', 't', 'o', 'm', 'D', 'i', 's', 't', 'r', 'i', 'b', 'u', 't', 'i', 'o', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*    68 - "test.labeledBooleanMetric" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'B', 'o', 'o', 'l', 'e', 'a', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*    94 - "test.labeledBooleanMetricLabels" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'B', 'o', 'o', 'l', 'e', 'a', 'n', 'M', 'e', 't', 'r', 'i', 'c', 'L', 'a', 'b', 'e', 'l', 's', '\0',
+  /*   126 - "test.labeledCounterMetric" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'C', 'o', 'u', 'n', 't', 'e', 'r', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   152 - "test.labeledCounterMetricLabels" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'C', 'o', 'u', 'n', 't', 'e', 'r', 'M', 'e', 't', 'r', 'i', 'c', 'L', 'a', 'b', 'e', 'l', 's', '\0',
+  /*   184 - "test.labeledStringMetric" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'S', 't', 'r', 'i', 'n', 'g', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   209 - "test.labeledStringMetricLabels" */ 't', 'e', 's', 't', '.', 'l', 'a', 'b', 'e', 'l', 'e', 'd', 'S', 't', 'r', 'i', 'n', 'g', 'M', 'e', 't', 'r', 'i', 'c', 'L', 'a', 'b', 'e', 'l', 's', '\0',
+  /*   240 - "test.memoryDistributionMetric" */ 't', 'e', 's', 't', '.', 'm', 'e', 'm', 'o', 'r', 'y', 'D', 'i', 's', 't', 'r', 'i', 'b', 'u', 't', 'i', 'o', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   270 - "test.stringListMetric" */ 't', 'e', 's', 't', '.', 's', 't', 'r', 'i', 'n', 'g', 'L', 'i', 's', 't', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   292 - "test.stringMetric" */ 't', 'e', 's', 't', '.', 's', 't', 'r', 'i', 'n', 'g', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   310 - "test.textMetric" */ 't', 'e', 's', 't', '.', 't', 'e', 'x', 't', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   326 - "test.timespanMetric" */ 't', 'e', 's', 't', '.', 't', 'i', 'm', 'e', 's', 'p', 'a', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   346 - "test.timingDistributionMetric" */ 't', 'e', 's', 't', '.', 't', 'i', 'm', 'i', 'n', 'g', 'D', 'i', 's', 't', 'r', 'i', 'b', 'u', 't', 'i', 'o', 'n', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   376 - "testNested.datetimeMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'd', 'a', 't', 'e', 't', 'i', 'm', 'e', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   402 - "testNested.eventMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'e', 'v', 'e', 'n', 't', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   425 - "testNested.eventMetricWithExtra" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'e', 'v', 'e', 'n', 't', 'M', 'e', 't', 'r', 'i', 'c', 'W', 'i', 't', 'h', 'E', 'x', 't', 'r', 'a', '\0',
+  /*   457 - "testNested.externalDenominator" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'e', 'x', 't', 'e', 'r', 'n', 'a', 'l', 'D', 'e', 'n', 'o', 'm', 'i', 'n', 'a', 't', 'o', 'r', '\0',
+  /*   488 - "testNested.optimizableCounterMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'o', 'p', 't', 'i', 'm', 'i', 'z', 'a', 'b', 'l', 'e', 'C', 'o', 'u', 'n', 't', 'e', 'r', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   524 - "testNested.quantityMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'q', 'u', 'a', 'n', 't', 'i', 't', 'y', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   550 - "testNested.rateMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'r', 'a', 't', 'e', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+  /*   572 - "testNested.rateWithExternalDenominator" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'r', 'a', 't', 'e', 'W', 'i', 't', 'h', 'E', 'x', 't', 'e', 'r', 'n', 'a', 'l', 'D', 'e', 'n', 'o', 'm', 'i', 'n', 'a', 't', 'o', 'r', '\0',
+  /*   611 - "testNested.uuidMetric" */ 't', 'e', 's', 't', 'N', 'e', 's', 't', 'e', 'd', '.', 'u', 'u', 'i', 'd', 'M', 'e', 't', 'r', 'i', 'c', '\0',
+};
+
+
+static_assert(sizeof(gMetricStringTable) < 4294967296, "Metric string table is too large.");
+
+const metric_entry_t sMetricByNameLookupEntries[] = {
+  6341068335467200838ull,
+  3458764548180279480ull,
+  1152921590506193384ull,
+  576460756598390784ull,
+  2882303787286921342ull,
+  6917529092065591642ull,
+  9799832883647480358ull,
+  2305843026393563204ull,
+  7493989848663982456ull,
+  1152921513196781587ull,
+  8070450609557340585ull,
+  2305843030688530526ull,
+  5188146822270419236ull,
+  8646911366155731401ull,
+  1729382269795172390ull,
+  10952754396844261987ull,
+  4035225309073637616ull,
+  10376293640245871164ull,
+  9223372127049089548ull,
+  5764607578868810038ull,
+  8070450605262373266ull,
+  2882303791581888664ull,
+  4611686065672028430ull,
+  3458764552475246801ull
+};
+
+
+
+Maybe<uint32_t>
+MetricByNameLookup(const nsACString& aKey)
+{
+  static const uint8_t BASES[] = {
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   1,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   3,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   1,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   2,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   3,   0,   0,   0,
+       0,   0,   0,   3,   0,   4,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   4,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   6,   0,  12,   0,   0,   0,   0,   0,   0,   0,
+      11,   0,   0,   0,   3,   0,   0,   3,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+  };
+  
+
+  const char* bytes = aKey.BeginReading();
+  size_t length = aKey.Length();
+  auto& entry = mozilla::perfecthash::Lookup(bytes, length, BASES,
+                                             sMetricByNameLookupEntries);
+  return metric_result_check(aKey, entry);
+}
+
+
+/**
+ * Get a category's name from the string table.
+ */
+const char* GetCategoryName(category_entry_t entry) {
+  MOZ_ASSERT(entry < sizeof(gCategoryStringTable), "Entry identifier offset larger than string table");
+  return &gCategoryStringTable[entry];
+}
+
+/**
+ * Get a metric's identifier from the string table.
+ */
+const char* GetMetricIdentifier(metric_entry_t entry) {
+  uint32_t offset = GLEAN_OFFSET(entry);
+  MOZ_ASSERT(offset < sizeof(gMetricStringTable), "Entry identifier offset larger than string table");
+  return &gMetricStringTable[offset];
+}
+
+/**
+ * Check that the found entry is pointing to the right key
+ * and return it.
+ * Or return `Nothing()` if the entry was not found.
+ */
+static Maybe<uint32_t> category_result_check(const nsACString& aKey, category_entry_t entry) {
+  if (MOZ_UNLIKELY(entry > sizeof(gCategoryStringTable))) {
+    return Nothing();
+  }
+  if (aKey.EqualsASCII(gCategoryStringTable + entry)) {
+    return Some(entry);
+  }
+  return Nothing();
+}
+
+/**
+ * Check if the found entry index is pointing to the right key
+ * and return the corresponding metric ID.
+ * Or return `Nothing()` if the entry was not found.
+ */
+static Maybe<uint32_t> metric_result_check(const nsACString& aKey, uint64_t entry) {
+  uint32_t metricId = entry >> GLEAN_INDEX_BITS;
+  uint32_t offset = GLEAN_OFFSET(entry);
+
+  if (offset > sizeof(gMetricStringTable)) {
+    return Nothing();
+  }
+
+  if (aKey.EqualsASCII(gMetricStringTable + offset)) {
+    return Some(metricId);
+  }
+
+  return Nothing();
+}
+
+
+#undef GLEAN_INDEX_BITS
+#undef GLEAN_ID_BITS
+#undef GLEAN_TYPE_ID
+#undef GLEAN_METRIC_ID
+#undef GLEAN_OFFSET
+
+} // namespace mozilla::glean
diff --git a/toolkit/components/glean/tests/pytest/metrics_test_output_js_h b/toolkit/components/glean/tests/pytest/metrics_test_output_js_h
new file mode 100644
index 0000000000..6ce9833732
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/metrics_test_output_js_h
@@ -0,0 +1,75 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#ifndef mozilla_GleanJSMetricsLookup_h
+#define mozilla_GleanJSMetricsLookup_h
+
+#include <cstdint>
+
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/glean/bindings/GleanMetric.h"
+#include "nsStringFwd.h"
+
+class nsISupports;
+
+namespace mozilla::glean {
+
+// The category lookup table's entry type
+using category_entry_t = uint32_t;
+// The metric lookup table's entry type
+// This is a bitpacked type with 32 bits available to index into
+// the string table, 5 bits available to signify the metric type,
+// and the remaining 27 bits devoted to 2 "signal"
+// bits to signify important characteristics (metric's a labeled metric's
+// submetric, metric's been registered at runtime) and 25 bits
+// for built-in metric ids.
+// Gives room for 33554432 of each combination of
+// characteristics (which hopefully will prove to be enough).
+using metric_entry_t = uint64_t;
+
+already_AddRefed<GleanMetric> NewMetricFromId(uint32_t id, nsISupports* aParent);
+
+/**
+ * Create a submetric instance for a labeled metric of the provided type and id for the given label.
+ * Assigns or retrieves an id for the submetric from the SDK.
+ *
+ * @param aParentTypeId - The type of the parent labeled metric identified as a number generated during codegen.
+ *                        Only used to identify which X of LabeledX you are so that X can be created here.
+ * @param aParentMetricId - The metric id for the parent labeled metric.
+ * @param aLabel - The label for the submetric. Might not adhere to the SDK label format.
+ * @param aSubmetricId - an outparam which is assigned the submetric's SDK-generated submetric id.
+ *                       Used only by GIFFT.
+ */
+already_AddRefed<GleanMetric> NewSubMetricFromIds(uint32_t aParentTypeId, uint32_t aParentMetricId, const nsACString& aLabel, uint32_t* aSubmetricId, nsISupports* aParent);
+
+/**
+ * Get a category's name from the string table.
+ */
+const char* GetCategoryName(category_entry_t entry);
+
+/**
+ * Get a metric's identifier from the string table.
+ */
+const char* GetMetricIdentifier(metric_entry_t entry);
+
+/**
+ * Get a metric's id given its name.
+ */
+Maybe<uint32_t> MetricByNameLookup(const nsACString&);
+
+/**
+ * Get a category's id given its name.
+ */
+Maybe<uint32_t> CategoryByNameLookup(const nsACString&);
+
+extern const category_entry_t sCategoryByNameLookupEntries[2];
+extern const metric_entry_t sMetricByNameLookupEntries[24];
+
+} // namespace mozilla::glean
+#endif // mozilla_GleanJSMetricsLookup_h
diff --git a/toolkit/components/glean/tests/pytest/pings_test.yaml b/toolkit/components/glean/tests/pytest/pings_test.yaml
new file mode 100644
index 0000000000..efa6ba9e0a
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/pings_test.yaml
@@ -0,0 +1,116 @@
+# 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/.
+
+# This file defines the built-in pings that are recorded by the Glean SDK. They
+# are automatically converted to Kotlin code at build time using the
+# `glean_parser` PyPI package.
+
+---
+$schema: moz://mozilla.org/schemas/glean/pings/1-0-0
+
+not-baseline:
+  description: >
+    This ping is intended to provide metrics that are managed by the library
+    itself, and not explicitly set by the application or included in the
+    application's `metrics.yaml` file.
+    The `baseline` ping is automatically sent when the application is moved to
+    the background.
+  include_client_id: true
+  bugs:
+    - https://bugzilla.mozilla.org/1512938
+    - https://bugzilla.mozilla.org/1599877
+  data_reviews:
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1512938#c3
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1599877#c25
+  notification_emails:
+    - glean-team@mozilla.com
+  reasons:
+    dirty_startup: |
+      The ping was submitted at startup, because the application process was
+      killed before the Glean SDK had the chance to generate this ping, when
+      going to background, in the last session.
+
+      *Note*: this ping will not contain the `glean.baseline.duration` metric.
+    background: |
+      The ping was submitted before going to background.
+    foreground: |
+      The ping was submitted when the application went to foreground, which
+      includes when the application starts.
+
+      *Note*: this ping will not contain the `glean.baseline.duration` metric.
+
+not-metrics:
+  description: >
+    The `metrics` ping is intended for all of the metrics that are explicitly
+    set by the application or are included in the application's `metrics.yaml`
+    file (except events).
+    The reported data is tied to the ping's *measurement window*, which is the
+    time between the collection of two `metrics` ping. Ideally, this window is
+    expected to be about 24 hours, given that the collection is scheduled daily
+    at 4AM. Data in the `ping_info` section of the ping can be used to infer the
+    length of this window.
+  include_client_id: true
+  bugs:
+    - https://bugzilla.mozilla.org/1512938
+  data_reviews:
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1512938#c3
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1557048#c13
+  notification_emails:
+    - glean-team@mozilla.com
+  reasons:
+    overdue: |
+      The last ping wasn't submitted on the current calendar day, but it's after
+      4am, so this ping submitted immediately
+    today: |
+      The last ping wasn't submitted on the current calendar day, but it is
+      still before 4am, so schedule to send this ping on the current calendar
+      day at 4am.
+    tomorrow: |
+      The last ping was already submitted on the current calendar day, so
+      schedule this ping for the next calendar day at 4am.
+    upgrade: |
+      This ping was submitted at startup because the application was just
+      upgraded.
+    reschedule: |
+      A ping was just submitted. This ping was rescheduled for the next calendar
+      day at 4am.
+
+not-events:
+  description: >
+    The events ping's purpose is to transport all of the event metric
+    information. The `events` ping is automatically sent when the application is
+    moved to the background.
+  include_client_id: true
+  bugs:
+    - https://bugzilla.mozilla.org/1512938
+  data_reviews:
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1512938#c3
+  notification_emails:
+    - glean-team@mozilla.com
+  reasons:
+    startup: |
+      The ping was submitted at startup. The events ping is always sent if there
+      are any pending events at startup, because event timestamps can not be
+      mixed across runs of the application.
+    background: |
+      The ping was submitted before going to background.
+    max_capacity: |
+      The maximum number of events was reached (default 500 events).
+
+not-deletion-request:
+  description: >
+    This ping is submitted when a user opts out of
+    sending technical and interaction data to Mozilla.
+    This ping is intended to communicate to the Data Pipeline
+    that the user wishes to have their reported Telemetry data deleted.
+    As such it attempts to send itself at the moment the user
+    opts out of data collection.
+  include_client_id: true
+  send_if_empty: true
+  bugs:
+    - https://bugzilla.mozilla.org/1587095
+  data_reviews:
+    - https://bugzilla.mozilla.org/show_bug.cgi?id=1587095#c6
+  notification_emails:
+    - glean-team@mozilla.com
diff --git a/toolkit/components/glean/tests/pytest/pings_test_output b/toolkit/components/glean/tests/pytest/pings_test_output
new file mode 100644
index 0000000000..9e037eb22a
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/pings_test_output
@@ -0,0 +1,118 @@
+// -*- mode: Rust -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+use crate::private::Ping;
+use once_cell::sync::Lazy;
+
+#[allow(non_upper_case_globals)]
+/// This ping is intended to provide metrics that are managed by the library
+/// itself, and not explicitly set by the application or included in the
+/// application's `metrics.yaml` file. The `baseline` ping is automatically sent
+/// when the application is moved to the background.
+pub static not_baseline: Lazy<Ping> = Lazy::new(|| {
+    Ping::new(
+        "not-baseline",
+        true,
+        false,
+        true,
+        vec!["background".into(), "dirty_startup".into(), "foreground".into()],
+    )
+});
+
+#[allow(non_upper_case_globals)]
+/// This ping is submitted when a user opts out of sending technical and
+/// interaction data to Mozilla. This ping is intended to communicate to the Data
+/// Pipeline that the user wishes to have their reported Telemetry data deleted. As
+/// such it attempts to send itself at the moment the user opts out of data
+/// collection.
+pub static not_deletion_request: Lazy<Ping> = Lazy::new(|| {
+    Ping::new(
+        "not-deletion-request",
+        true,
+        true,
+        true,
+        vec![],
+    )
+});
+
+#[allow(non_upper_case_globals)]
+/// The events ping's purpose is to transport all of the event metric information.
+/// The `events` ping is automatically sent when the application is moved to the
+/// background.
+pub static not_events: Lazy<Ping> = Lazy::new(|| {
+    Ping::new(
+        "not-events",
+        true,
+        false,
+        true,
+        vec!["background".into(), "max_capacity".into(), "startup".into()],
+    )
+});
+
+#[allow(non_upper_case_globals)]
+/// The `metrics` ping is intended for all of the metrics that are explicitly set
+/// by the application or are included in the application's `metrics.yaml` file
+/// (except events). The reported data is tied to the ping's *measurement window*,
+/// which is the time between the collection of two `metrics` ping. Ideally, this
+/// window is expected to be about 24 hours, given that the collection is scheduled
+/// daily at 4AM. Data in the `ping_info` section of the ping can be used to infer
+/// the length of this window.
+pub static not_metrics: Lazy<Ping> = Lazy::new(|| {
+    Ping::new(
+        "not-metrics",
+        true,
+        false,
+        true,
+        vec!["overdue".into(), "reschedule".into(), "today".into(), "tomorrow".into(), "upgrade".into()],
+    )
+});
+
+
+/// Instantiate custom pings once to trigger registration.
+///
+/// # Arguments
+///
+/// application_id: If present, limit to only registering custom pings
+///                 assigned to the identified application.
+#[doc(hidden)]
+pub fn register_pings(application_id: Option<&str>) {
+    match application_id {
+        _ => {
+            let _ = &*not_baseline;
+            let _ = &*not_deletion_request;
+            let _ = &*not_events;
+            let _ = &*not_metrics;
+        }
+    }
+}
+
+#[cfg(feature = "with_gecko")]
+pub(crate) fn submit_ping_by_id(id: u32, reason: Option<&str>) {
+    if id & (1 << crate::factory::DYNAMIC_PING_BIT) > 0 {
+        let map = crate::factory::__jog_metric_maps::PING_MAP
+            .read()
+            .expect("Read lock for dynamic ping map was poisoned!");
+        if let Some(ping) = map.get(&id) {
+            ping.submit(reason);
+        } else {
+            // TODO: instrument this error.
+            log::error!("Cannot submit unknown dynamic ping {} by id.", id);
+        }
+        return;
+    }
+    match id {
+        1 => not_baseline.submit(reason),
+        2 => not_deletion_request.submit(reason),
+        3 => not_events.submit(reason),
+        4 => not_metrics.submit(reason),
+        _ => {
+            // TODO: instrument this error.
+            log::error!("Cannot submit unknown ping {} by id.", id);
+        }
+    }
+}
diff --git a/toolkit/components/glean/tests/pytest/pings_test_output_cpp b/toolkit/components/glean/tests/pytest/pings_test_output_cpp
new file mode 100644
index 0000000000..289529b118
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/pings_test_output_cpp
@@ -0,0 +1,62 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#ifndef mozilla_glean_Pings_h
+#define mozilla_glean_Pings_h
+
+#include "mozilla/glean/bindings/Ping.h"
+
+namespace mozilla::glean_pings {
+
+/*
+ * Generated from not-baseline.
+ *
+ * This ping is intended to provide metrics that are managed by the library
+ * itself, and not explicitly set by the application or included in the
+ * application's `metrics.yaml` file. The `baseline` ping is automatically sent
+ * when the application is moved to the background.
+ */
+constexpr glean::impl::Ping NotBaseline(1);
+
+/*
+ * Generated from not-deletion-request.
+ *
+ * This ping is submitted when a user opts out of sending technical and
+ * interaction data to Mozilla. This ping is intended to communicate to the Data
+ * Pipeline that the user wishes to have their reported Telemetry data deleted. As
+ * such it attempts to send itself at the moment the user opts out of data
+ * collection.
+ */
+constexpr glean::impl::Ping NotDeletionRequest(2);
+
+/*
+ * Generated from not-events.
+ *
+ * The events ping's purpose is to transport all of the event metric information.
+ * The `events` ping is automatically sent when the application is moved to the
+ * background.
+ */
+constexpr glean::impl::Ping NotEvents(3);
+
+/*
+ * Generated from not-metrics.
+ *
+ * The `metrics` ping is intended for all of the metrics that are explicitly set
+ * by the application or are included in the application's `metrics.yaml` file
+ * (except events). The reported data is tied to the ping's *measurement window*,
+ * which is the time between the collection of two `metrics` ping. Ideally, this
+ * window is expected to be about 24 hours, given that the collection is scheduled
+ * daily at 4AM. Data in the `ping_info` section of the ping can be used to infer
+ * the length of this window.
+ */
+constexpr glean::impl::Ping NotMetrics(4);
+
+
+}  // namespace mozilla::glean_pings
+
+#endif  // mozilla_glean_Pings_h
diff --git a/toolkit/components/glean/tests/pytest/pings_test_output_js_cpp b/toolkit/components/glean/tests/pytest/pings_test_output_js_cpp
new file mode 100644
index 0000000000..139eb29148
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/pings_test_output_js_cpp
@@ -0,0 +1,162 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#include "mozilla/glean/bindings/GleanJSPingsLookup.h"
+
+#include "mozilla/PerfectHash.h"
+#include "nsString.h"
+
+#include "mozilla/PerfectHash.h"
+
+#define GLEAN_PING_INDEX_BITS (16)
+#define GLEAN_PING_ID(entry) ((entry) >> GLEAN_PING_INDEX_BITS)
+#define GLEAN_PING_INDEX(entry) ((entry) & ((1UL << GLEAN_PING_INDEX_BITS) - 1))
+
+namespace mozilla::glean {
+
+// Contains the ping id and the index into the ping string table.
+using ping_entry_t = uint32_t;
+
+Maybe<uint32_t> ping_result_check(const nsACString& aKey, ping_entry_t aEntry);
+
+#if defined(_MSC_VER) && !defined(__clang__)
+const char gPingStringTable[] = {
+#else
+constexpr char gPingStringTable[] = {
+#endif
+  /*     0 - "notBaseline" */ 'n', 'o', 't', 'B', 'a', 's', 'e', 'l', 'i', 'n', 'e', '\0',
+  /*    12 - "notDeletionRequest" */ 'n', 'o', 't', 'D', 'e', 'l', 'e', 't', 'i', 'o', 'n', 'R', 'e', 'q', 'u', 'e', 's', 't', '\0',
+  /*    31 - "notEvents" */ 'n', 'o', 't', 'E', 'v', 'e', 'n', 't', 's', '\0',
+  /*    41 - "notMetrics" */ 'n', 'o', 't', 'M', 'e', 't', 'r', 'i', 'c', 's', '\0',
+};
+
+
+
+const ping_entry_t sPingByNameLookupEntries[] = {
+  65536,
+  131084,
+  196639,
+  262185
+};
+
+
+
+Maybe<uint32_t>
+PingByNameLookup(const nsACString& aKey)
+{
+  static const uint8_t BASES[] = {
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   2,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   2,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+       0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,
+  };
+  
+
+  const char* bytes = aKey.BeginReading();
+  size_t length = aKey.Length();
+  auto& entry = mozilla::perfecthash::Lookup(bytes, length, BASES,
+                                             sPingByNameLookupEntries);
+  return ping_result_check(aKey, entry);
+}
+
+
+/**
+ * Get a ping's name given its entry from the PHF.
+ */
+const char* GetPingName(ping_entry_t aEntry) {
+  uint32_t idx = GLEAN_PING_INDEX(aEntry);
+  MOZ_ASSERT(idx < sizeof(gPingStringTable), "Ping index larger than string table");
+  return &gPingStringTable[idx];
+}
+
+/**
+ * Check if the found entry is pointing at the correct ping.
+ * PHF can false-positive a result when the key isn't present, so we check
+ * for a string match. If it fails, return Nothing(). If we found it,
+ * return the ping's id.
+ */
+Maybe<uint32_t> ping_result_check(const nsACString& aKey, ping_entry_t aEntry) {
+  uint32_t idx = GLEAN_PING_INDEX(aEntry);
+  uint32_t id = GLEAN_PING_ID(aEntry);
+
+  if (MOZ_UNLIKELY(idx > sizeof(gPingStringTable))) {
+    return Nothing();
+  }
+
+  if (aKey.EqualsASCII(&gPingStringTable[idx])) {
+    return Some(id);
+  }
+
+  return Nothing();
+}
+
+#undef GLEAN_PING_INDEX_BITS
+#undef GLEAN_PING_ID
+#undef GLEAN_PING_INDEX
+
+}  // namespace mozilla::glean
diff --git a/toolkit/components/glean/tests/pytest/pings_test_output_js_h b/toolkit/components/glean/tests/pytest/pings_test_output_js_h
new file mode 100644
index 0000000000..0c89de93ae
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/pings_test_output_js_h
@@ -0,0 +1,33 @@
+// -*- mode: C++ -*-
+
+// AUTOGENERATED BY glean_parser.  DO NOT EDIT.
+
+/* 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/. */
+
+#ifndef mozilla_GleanJSPingsLookup_h
+#define mozilla_GleanJSPingsLookup_h
+
+#include <cstdint>
+#include "mozilla/Maybe.h"
+#include "nsStringFwd.h"
+
+namespace mozilla::glean {
+
+// Contains the ping id and the index into the ping string table.
+using ping_entry_t = uint32_t;
+
+/**
+ * Get a ping's name given its entry in the PHF.
+ */
+const char* GetPingName(ping_entry_t aEntry);
+
+/**
+ * Get a ping's id given its name.
+ */
+Maybe<uint32_t> PingByNameLookup(const nsACString&);
+
+extern const ping_entry_t sPingByNameLookupEntries[4];
+}  // namespace mozilla::glean
+#endif  // mozilla_GleanJSPingsLookup_h
diff --git a/toolkit/components/glean/tests/pytest/python.toml b/toolkit/components/glean/tests/pytest/python.toml
new file mode 100644
index 0000000000..86c0f55cfa
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/python.toml
@@ -0,0 +1,16 @@
+[DEFAULT]
+subsuite = "fog"
+
+["test_gifft.py"]
+
+["test_glean_parser_cpp.py"]
+
+["test_glean_parser_js.py"]
+
+["test_glean_parser_rust.py"]
+
+["test_jogfile_output.py"]
+
+["test_no_expired_metrics.py"]
+
+["test_yaml_indices.py"]
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()
diff --git a/toolkit/components/glean/tests/pytest/test_glean_parser_cpp.py b/toolkit/components/glean/tests/pytest/test_glean_parser_cpp.py
new file mode 100644
index 0000000000..05fd691782
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_glean_parser_cpp.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 io
+import sys
+from os import path
+from pathlib import Path
+
+import mozunit
+from expect_helper import expect
+
+# Shenanigans to import the cpp outputter extension
+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 cpp
+import run_glean_parser
+
+
+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 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}
+    input_files = [Path(path.join(path.dirname(__file__), "metrics_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd = io.StringIO()
+    cpp.output_cpp(all_objs, output_fd, options)
+
+    expect(
+        path.join(path.dirname(__file__), "metrics_test_output_cpp"),
+        output_fd.getvalue(),
+    )
+
+
+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_cpp`.
+    Expect it to be fragile.
+    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}
+    input_files = [Path(path.join(path.dirname(__file__), "pings_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd = io.StringIO()
+    cpp.output_cpp(all_objs, output_fd, options)
+
+    expect(
+        path.join(path.dirname(__file__), "pings_test_output_cpp"), output_fd.getvalue()
+    )
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/glean/tests/pytest/test_glean_parser_js.py b/toolkit/components/glean/tests/pytest/test_glean_parser_js.py
new file mode 100644
index 0000000000..3f4a37e797
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_glean_parser_js.py
@@ -0,0 +1,84 @@
+# 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 js outputter extension
+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
+
+import js
+
+
+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 new expected output files, set `UPDATE_EXPECT=1` when running the test suite:
+
+    UPDATE_EXPECT=1 mach test toolkit/components/glean/tests/pytest
+    """
+
+    options = {"allow_reserved": False}
+    input_files = [Path(path.join(path.dirname(__file__), "metrics_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd_h = io.StringIO()
+    output_fd_cpp = io.StringIO()
+    js.output_js(all_objs, output_fd_h, output_fd_cpp, options)
+
+    expect(
+        path.join(path.dirname(__file__), "metrics_test_output_js_h"),
+        output_fd_h.getvalue(),
+    )
+
+    expect(
+        path.join(path.dirname(__file__), "metrics_test_output_js_cpp"),
+        output_fd_cpp.getvalue(),
+    )
+
+
+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 new expected output files, set `UPDATE_EXPECT=1` when running the test suite:
+
+    UPDATE_EXPECT=1 mach test toolkit/components/glean/tests/pytest
+    """
+
+    options = {"allow_reserved": False}
+    input_files = [Path(path.join(path.dirname(__file__), "pings_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd_h = io.StringIO()
+    output_fd_cpp = io.StringIO()
+    js.output_js(all_objs, output_fd_h, output_fd_cpp, options)
+
+    expect(
+        path.join(path.dirname(__file__), "pings_test_output_js_h"),
+        output_fd_h.getvalue(),
+    )
+
+    expect(
+        path.join(path.dirname(__file__), "pings_test_output_js_cpp"),
+        output_fd_cpp.getvalue(),
+    )
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/glean/tests/pytest/test_glean_parser_rust.py b/toolkit/components/glean/tests/pytest/test_glean_parser_rust.py
new file mode 100644
index 0000000000..329c7ed348
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_glean_parser_rust.py
@@ -0,0 +1,89 @@
+# 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 rust outputter extension
+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
+import rust
+
+# 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"))
+
+
+def test_all_metric_types():
+    """Honestly, this is a pretty bad test.
+    It generates Rust for a given test metrics.yaml and compares it byte-for-byte
+    with an expected output Rust file.
+    Expect it to be fragile.
+    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}
+    input_files = [Path(path.join(path.dirname(__file__), "metrics_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd = io.StringIO()
+    rust.output_rust(all_objs, output_fd, {}, options)
+
+    expect(
+        path.join(path.dirname(__file__), "metrics_test_output"), output_fd.getvalue()
+    )
+
+
+def test_fake_pings():
+    """Another similarly-bad test.
+    It generates Rust for pings_test.yaml, comparing it byte-for-byte
+    with an expected output Rust file.
+    Expect it to be fragile.
+    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}
+    input_files = [Path(path.join(path.dirname(__file__), "pings_test.yaml"))]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd = io.StringIO()
+    rust.output_rust(all_objs, output_fd, {}, options)
+
+    expect(path.join(path.dirname(__file__), "pings_test_output"), output_fd.getvalue())
+
+
+def test_expires_version():
+    """This test relies on the intermediary object format output by glean_parser.
+    Expect it to be fragile on glean_parser updates that change that format.
+    """
+
+    # The test file has 41, 42, 100. Use 42.0a1 here to ensure "expires == version" means expired.
+    options = run_glean_parser.get_parser_options("42.0a1")
+    input_files = [
+        Path(path.join(path.dirname(__file__), "metrics_expires_versions_test.yaml"))
+    ]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    assert all_objs["test"]["expired1"].disabled is True
+    assert all_objs["test"]["expired2"].disabled is True
+    assert all_objs["test"]["unexpired"].disabled is False
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/glean/tests/pytest/test_jogfile_output.py b/toolkit/components/glean/tests/pytest/test_jogfile_output.py
new file mode 100644
index 0000000000..801c0967ff
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_jogfile_output.py
@@ -0,0 +1,50 @@
+# 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 jog
+import run_glean_parser
+
+
+def test_jogfile_output():
+    """
+    A regression test. Very fragile.
+    It generates a jogfile for metrics_test.yaml and compares it
+    byte-for-byte with an expected output file.
+
+    Also, part one of a two-part test.
+    The generated jogfile is consumed in Rust_TestJogfile in t/c/g/tests/gtest/test.rs
+    This is to ensure that the jogfile we generate in Python can be consumed in Rust.
+
+    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", here_path / "pings_test.yaml"]
+
+    all_objs, options = run_glean_parser.parse_with_options(input_files, options)
+
+    output_fd = io.StringIO()
+    jog.output_file(all_objs, output_fd, options)
+
+    expect(here_path / "jogfile_output", output_fd.getvalue())
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/glean/tests/pytest/test_no_expired_metrics.py b/toolkit/components/glean/tests/pytest/test_no_expired_metrics.py
new file mode 100644
index 0000000000..9783acaf0a
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_no_expired_metrics.py
@@ -0,0 +1,46 @@
+# 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
+from os import path
+from pathlib import Path
+
+import mozunit
+
+# Shenanigans to import the metrics index's list of metrics.yamls
+FOG_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(FOG_ROOT_PATH)
+from metrics_index import metrics_yamls, tags_yamls
+
+# Shenanigans to import run_glean_parser
+sys.path.append(path.join(FOG_ROOT_PATH, "build_scripts", "glean_parser_ext"))
+import run_glean_parser
+
+# 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_no_metrics_expired():
+    """
+    Of all the metrics included in this build, are any expired?
+    If so, they must be removed or renewed.
+
+    (This also checks other lints, as a treat.)
+    """
+    with open("browser/config/version.txt", "r") as version_file:
+        app_version = version_file.read().strip()
+
+    options = run_glean_parser.get_parser_options(app_version)
+    paths = [Path(x) for x in metrics_yamls] + [Path(x) for x in tags_yamls]
+    all_objs = parser.parse_objects(paths, options)
+    assert not util.report_validation_errors(all_objs)
+    assert not lint.lint_metrics(all_objs.value, options)
+
+
+if __name__ == "__main__":
+    mozunit.main()
diff --git a/toolkit/components/glean/tests/pytest/test_yaml_indices.py b/toolkit/components/glean/tests/pytest/test_yaml_indices.py
new file mode 100644
index 0000000000..9ccde409e5
--- /dev/null
+++ b/toolkit/components/glean/tests/pytest/test_yaml_indices.py
@@ -0,0 +1,42 @@
+# 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
+from os import path
+
+import mozunit
+
+# Shenanigans to import the metrics index's lists of yamls
+FOG_ROOT_PATH = path.abspath(
+    path.join(path.dirname(__file__), path.pardir, path.pardir)
+)
+sys.path.append(FOG_ROOT_PATH)
+import metrics_index
+
+
+def test_yamls_sorted():
+    """
+    Ensure the yamls indices are sorted lexicographically.
+    """
+    # Ignore lists that are the concatenation of others.
+    to_ignore = ["metrics_yamls", "pings_yamls"]
+
+    # Fetch names of all variables defined in the `metrics_index` module.
+    yaml_lists = [
+        item
+        for item in dir(metrics_index)
+        if isinstance(getattr(metrics_index, item), list) and not item.startswith("__")
+    ]
+    for name in yaml_lists:
+        if name in to_ignore:
+            continue
+
+        yamls_to_test = metrics_index.__dict__[name]
+        assert (
+            sorted(yamls_to_test) == yamls_to_test
+        ), f"{name} must be be lexicographically sorted."
+
+
+if __name__ == "__main__":
+    mozunit.main()