test: add tests with different timezones

evgeniy-scherbina · evgeniy-scherbina · commit 0643747710ac · 2025-06-05T15:05:55.000Z
diff --git a/coderd/prebuilds/preset_snapshot.go b/coderd/prebuilds/preset_snapshot.go
@@ -1,6 +1,7 @@
 package prebuilds
 
 import (
+	"fmt"
 	"github.com/coder/coder/v2/coderd/schedule/cron"
 	"golang.org/x/xerrors"
 	"slices"
@@ -102,16 +103,15 @@ func (p PresetSnapshot) CalculateDesiredInstances(at time.Time) (int32, error) {
 		return p.Preset.DesiredInstances.Int32, nil
 	}
 
-	loc, err := time.LoadLocation(p.Preset.AutoscalingTimezone)
+	_, err := time.LoadLocation(p.Preset.AutoscalingTimezone)
 	if err != nil {
 		return 0, xerrors.Errorf("can't parse location %v: %w", p.Preset.AutoscalingTimezone, err)
 	}
 
-	at = at.In(loc)
-
 	// Check each schedule
 	for _, schedule := range p.PrebuildSchedules {
-		matches, err := MatchesCron(schedule.CronExpression, at)
+		cronExprWithTimezone := fmt.Sprintf("CRON_TZ=%s %s", p.Preset.AutoscalingTimezone, schedule.CronExpression)
+		matches, err := MatchesCron(cronExprWithTimezone, at)
 		if err != nil {
 			return 0, xerrors.Errorf("failed to match cron expression: %w", err)
 		}
diff --git a/coderd/prebuilds/preset_snapshot_test.go b/coderd/prebuilds/preset_snapshot_test.go
@@ -1178,6 +1178,53 @@ func TestCalculateDesiredInstances(t *testing.T) {
 			at:                          mustParseTime(t, time.RFC1123, "Sat, 07 Jun 2025 14:00:00 UTC"),
 			expectedCalculatedInstances: 1,
 		},
+
+		// Test different timezones
+		{
+			name: "3PM UTC - 8AM America/Los_Angeles; An hour before the start of the time range",
+			snapshot: mkSnapshot(
+				mkPreset(1, "America/Los_Angeles"),
+				mkSchedule("* 9-13 * * 1-5", 3),
+			),
+			at:                          mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 15:00:00 UTC"),
+			expectedCalculatedInstances: 1,
+		},
+		{
+			name: "4PM UTC - 9AM America/Los_Angeles; Start of the time range",
+			snapshot: mkSnapshot(
+				mkPreset(1, "America/Los_Angeles"),
+				mkSchedule("* 9-13 * * 1-5", 3),
+			),
+			at:                          mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 16:00:00 UTC"),
+			expectedCalculatedInstances: 3,
+		},
+		{
+			name: "8:58PM UTC - 1:58PM America/Los_Angeles; Right before the end of the time range",
+			snapshot: mkSnapshot(
+				mkPreset(1, "America/Los_Angeles"),
+				mkSchedule("* 9-13 * * 1-5", 3),
+			),
+			at:                          mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 20:58:00 UTC"),
+			expectedCalculatedInstances: 3,
+		},
+		{
+			name: "9PM UTC - 2PM America/Los_Angeles; Right after the end of the time range",
+			snapshot: mkSnapshot(
+				mkPreset(1, "America/Los_Angeles"),
+				mkSchedule("* 9-13 * * 1-5", 3),
+			),
+			at:                          mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 21:00:00 UTC"),
+			expectedCalculatedInstances: 1,
+		},
+		{
+			name: "11PM UTC - 4PM America/Los_Angeles; Outside the time range",
+			snapshot: mkSnapshot(
+				mkPreset(1, "America/Los_Angeles"),
+				mkSchedule("* 9-13 * * 1-5", 3),
+			),
+			at:                          mustParseTime(t, time.RFC1123, "Mon, 02 Jun 2025 23:00:00 UTC"),
+			expectedCalculatedInstances: 1,
+		},
 	}
 
 	for _, tc := range testCases {
