From 8e5cfbe4ab11713e383b3ff0d978f116320de2a3 Mon Sep 17 00:00:00 2001
From: Nick Khyl <nickk@tailscale.com>
Date: Fri, 22 Nov 2024 09:05:01 -0600
Subject: [PATCH] util/syspolicy/rsop: reduce policyReloadMinDelay and
 policyReloadMaxDelay when in tests

These delays determine how soon syspolicy change callbacks are invoked after a policy setting is updated
in a policy source. For tests, we shorten these delays to minimize unnecessary wait times. This adjustment
only affects tests that subscribe to policy change notifications and modify policy settings after they have
already been set. Initial policy settings are always available immediately without delay.

Updates #12687

Signed-off-by: Nick Khyl <nickk@tailscale.com>
---
 util/syspolicy/rsop/resultant_policy.go      |  7 +++++++
 util/syspolicy/rsop/resultant_policy_test.go | 13 ++++---------
 util/syspolicy/rsop/store_registration.go    |  4 ++++
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/util/syspolicy/rsop/resultant_policy.go b/util/syspolicy/rsop/resultant_policy.go
index 019b8f602..b811a00ee 100644
--- a/util/syspolicy/rsop/resultant_policy.go
+++ b/util/syspolicy/rsop/resultant_policy.go
@@ -11,6 +11,7 @@
 	"sync/atomic"
 	"time"
 
+	"tailscale.com/util/syspolicy/internal"
 	"tailscale.com/util/syspolicy/internal/loggerx"
 	"tailscale.com/util/syspolicy/setting"
 
@@ -447,3 +448,9 @@ func (p *Policy) Close() {
 		go p.closeInternal()
 	}
 }
+
+func setForTest[T any](tb internal.TB, target *T, newValue T) {
+	oldValue := *target
+	tb.Cleanup(func() { *target = oldValue })
+	*target = newValue
+}
diff --git a/util/syspolicy/rsop/resultant_policy_test.go b/util/syspolicy/rsop/resultant_policy_test.go
index b2408c7f7..e4bfb1a88 100644
--- a/util/syspolicy/rsop/resultant_policy_test.go
+++ b/util/syspolicy/rsop/resultant_policy_test.go
@@ -574,9 +574,6 @@ func TestPolicyChangeHasChanged(t *testing.T) {
 }
 
 func TestChangePolicySetting(t *testing.T) {
-	setForTest(t, &policyReloadMinDelay, 100*time.Millisecond)
-	setForTest(t, &policyReloadMaxDelay, 500*time.Millisecond)
-
 	// Register policy settings used in this test.
 	settingA := setting.NewDefinition("TestSettingA", setting.DeviceSetting, setting.StringValue)
 	settingB := setting.NewDefinition("TestSettingB", setting.DeviceSetting, setting.StringValue)
@@ -589,6 +586,10 @@ func TestChangePolicySetting(t *testing.T) {
 	if _, err := RegisterStoreForTest(t, "TestSource", setting.DeviceScope, store); err != nil {
 		t.Fatalf("Failed to register policy store: %v", err)
 	}
+
+	setForTest(t, &policyReloadMinDelay, 100*time.Millisecond)
+	setForTest(t, &policyReloadMaxDelay, 500*time.Millisecond)
+
 	policy, err := policyForTest(t, setting.DeviceScope)
 	if err != nil {
 		t.Fatalf("Failed to get effective policy: %v", err)
@@ -978,9 +979,3 @@ func policyForTest(tb testing.TB, target setting.PolicyScope) (*Policy, error) {
 	})
 	return policy, nil
 }
-
-func setForTest[T any](tb testing.TB, target *T, newValue T) {
-	oldValue := *target
-	tb.Cleanup(func() { *target = oldValue })
-	*target = newValue
-}
diff --git a/util/syspolicy/rsop/store_registration.go b/util/syspolicy/rsop/store_registration.go
index 09c83e988..f9836846e 100644
--- a/util/syspolicy/rsop/store_registration.go
+++ b/util/syspolicy/rsop/store_registration.go
@@ -7,6 +7,7 @@
 	"errors"
 	"sync"
 	"sync/atomic"
+	"time"
 
 	"tailscale.com/util/syspolicy/internal"
 	"tailscale.com/util/syspolicy/setting"
@@ -33,6 +34,9 @@ func RegisterStore(name string, scope setting.PolicyScope, store source.Store) (
 // RegisterStoreForTest is like [RegisterStore], but unregisters the store when
 // tb and all its subtests complete.
 func RegisterStoreForTest(tb internal.TB, name string, scope setting.PolicyScope, store source.Store) (*StoreRegistration, error) {
+	setForTest(tb, &policyReloadMinDelay, 10*time.Millisecond)
+	setForTest(tb, &policyReloadMaxDelay, 500*time.Millisecond)
+
 	reg, err := RegisterStore(name, scope, store)
 	if err == nil {
 		tb.Cleanup(func() {