From c6ac4e0d347179212e3797cd9ed69f2f47261b28 Mon Sep 17 00:00:00 2001
From: Min RK <benjaminrk@gmail.com>
Date: Thu, 1 Dec 2022 08:57:43 +0100
Subject: [PATCH] test active users metrics

---
 jupyterhub/metrics.py            |  5 ++-
 jupyterhub/tests/test_metrics.py | 66 +++++++++++++++++++++++++++++++-
 2 files changed, 68 insertions(+), 3 deletions(-)

diff --git a/jupyterhub/metrics.py b/jupyterhub/metrics.py
index 156796f1..eb3cff03 100644
--- a/jupyterhub/metrics.py
+++ b/jupyterhub/metrics.py
@@ -19,7 +19,7 @@ them manually here.
 
     added ``jupyterhub_`` prefix to metric names.
 """
-from datetime import datetime, timedelta
+from datetime import timedelta
 from enum import Enum
 
 from prometheus_client import Gauge, Histogram
@@ -28,6 +28,7 @@ from traitlets import Any, Bool, Integer
 from traitlets.config import LoggingConfigurable
 
 from . import orm
+from .utils import utcnow
 
 REQUEST_DURATION_SECONDS = Histogram(
     'jupyterhub_request_duration_seconds',
@@ -265,7 +266,7 @@ class PeriodicMetricsCollector(LoggingConfigurable):
         # All the metrics should be based off a cutoff from a *fixed* point, so we calculate
         # the fixed point here - and then calculate the individual cutoffs in relation to this
         # fixed point.
-        now = datetime.utcnow()
+        now = utcnow()
         cutoffs = {
             ActiveUserPeriods.twenty_four_hours: now - timedelta(hours=24),
             ActiveUserPeriods.seven_days: now - timedelta(days=7),
diff --git a/jupyterhub/tests/test_metrics.py b/jupyterhub/tests/test_metrics.py
index 072dba7b..cf6586eb 100644
--- a/jupyterhub/tests/test_metrics.py
+++ b/jupyterhub/tests/test_metrics.py
@@ -1,11 +1,13 @@
 import json
+from datetime import timedelta
 from unittest import mock
 
 import pytest
 
 from jupyterhub import metrics, orm, roles
 
-from .utils import api_request, get_page
+from ..utils import utcnow
+from .utils import add_user, api_request, get_page
 
 
 async def test_total_users(app):
@@ -73,3 +75,65 @@ async def test_metrics_auth(
     else:
         assert r.status_code == 403
         assert 'read:metrics' in r.text
+
+
+async def test_active_users(app):
+    db = app.db
+    collector = metrics.PeriodicMetricsCollector(db=db)
+    collector.update()
+    now = utcnow()
+
+    def collect():
+        samples = metrics.ACTIVE_USERS.collect()[0].samples
+        by_period = {
+            metrics.ActiveUserPeriods(sample.labels["period"]): sample.value
+            for sample in samples
+        }
+        print(by_period)
+        return by_period
+
+    baseline = collect()
+
+    for i, offset in enumerate(
+        [
+            None,
+            # in 24h
+            timedelta(hours=23, minutes=30),
+            # in 7d
+            timedelta(hours=24, minutes=1),
+            timedelta(days=6, hours=23, minutes=30),
+            # in 30d
+            timedelta(days=7, minutes=1),
+            timedelta(days=29, hours=23, minutes=30),
+            # not in any
+            timedelta(days=30, minutes=1),
+        ]
+    ):
+        user = add_user(db, name=f"active-{i}")
+        if offset:
+            user.last_activity = now - offset
+        else:
+            user.last_activity = None
+        db.commit()
+
+    # collect before update is called, don't include new users
+    counts = collect()
+    for period in metrics.ActiveUserPeriods:
+        assert period in counts
+        assert counts[period] == baseline[period]
+
+    # collect after updates, check updated counts
+    collector.update()
+    counts = collect()
+    assert (
+        counts[metrics.ActiveUserPeriods.twenty_four_hours]
+        == baseline[metrics.ActiveUserPeriods.twenty_four_hours] + 1
+    )
+    assert (
+        counts[metrics.ActiveUserPeriods.seven_days]
+        == baseline[metrics.ActiveUserPeriods.seven_days] + 3
+    )
+    assert (
+        counts[metrics.ActiveUserPeriods.thirty_days]
+        == baseline[metrics.ActiveUserPeriods.thirty_days] + 5
+    )