util/syspolicy/policytest: move policy test helper to its own package

Updates #16998
Updates #12614

Change-Id: I9fd27d653ebee547951705dc5597481e85b60747
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

ipn/ipnlocal/local_test.go

@@ -64,7 +64,7 @@ import (
 	"tailscale.com/util/set"
 	"tailscale.com/util/syspolicy"
 	"tailscale.com/util/syspolicy/pkey"
-	"tailscale.com/util/syspolicy/policyclient"
+	"tailscale.com/util/syspolicy/policytest"
 	"tailscale.com/util/syspolicy/setting"
 	"tailscale.com/util/syspolicy/source"
 	"tailscale.com/wgengine"
@@ -1183,7 +1183,7 @@ func TestConfigureExitNode(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
-			var pol testPolicy
+			var pol policytest.Config
 			// Configure policy settings, if any.
 			if tt.exitNodeIDPolicy != nil {
 				pol.Set(pkey.ExitNodeID, string(*tt.exitNodeIDPolicy))
@@ -5539,62 +5539,6 @@ func TestReadWriteRouteInfo(t *testing.T) {
 	}
 }
 
-// testPolicy is a [policyclient.Client] with a static mapping of values.
-// The map value must be of the correct type (string, []string, bool, etc).
-//
-// It is used for testing purposes to simulate policy client behavior.
-// It panics if the values are the wrong type.
-type testPolicy struct {
-	v map[pkey.Key]any
-	policyclient.NoPolicyClient
-}
-
-func (sp *testPolicy) Set(key pkey.Key, value any) {
-	if sp.v == nil {
-		sp.v = make(map[pkey.Key]any)
-	}
-	sp.v[key] = value
-}
-
-func (sp testPolicy) GetStringArray(key pkey.Key, defaultVal []string) ([]string, error) {
-	if val, ok := sp.v[key]; ok {
-		if arr, ok := val.([]string); ok {
-			return arr, nil
-		}
-		panic(fmt.Sprintf("key %s is not a []string", key))
-	}
-	return defaultVal, nil
-}
-
-func (sp testPolicy) GetString(key pkey.Key, defaultVal string) (string, error) {
-	if val, ok := sp.v[key]; ok {
-		if str, ok := val.(string); ok {
-			return str, nil
-		}
-		panic(fmt.Sprintf("key %s is not a string", key))
-	}
-	return defaultVal, nil
-}
-
-func (sp testPolicy) GetBoolean(key pkey.Key, defaultVal bool) (bool, error) {
-	if val, ok := sp.v[key]; ok {
-		if b, ok := val.(bool); ok {
-			return b, nil
-		}
-		panic(fmt.Sprintf("key %s is not a bool", key))
-	}
-	return defaultVal, nil
-}
-
-func (sp testPolicy) HasAnyOf(keys ...pkey.Key) (bool, error) {
-	for _, key := range keys {
-		if _, ok := sp.v[key]; ok {
-			return true, nil
-		}
-	}
-	return false, nil
-}
-
 func TestFillAllowedSuggestions(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -5628,7 +5572,7 @@ func TestFillAllowedSuggestions(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			var pol testPolicy
+			var pol policytest.Config
 			pol.Set(pkey.AllowedSuggestedExitNodes, tt.allowPolicy)
 
 			got := fillAllowedSuggestions(pol)

util/syspolicy/policytest/policytest.go

@@ -0,0 +1,117 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Package policytest contains test helpers for the syspolicy packages.
+package policytest
+
+import (
+	"fmt"
+	"time"
+
+	"tailscale.com/util/syspolicy/pkey"
+	"tailscale.com/util/syspolicy/policyclient"
+	"tailscale.com/util/syspolicy/ptype"
+)
+
+// Config is a [policyclient.Client] implementation with a static mapping of
+// values.
+//
+// It is used for testing purposes to simulate policy client behavior.
+//
+// It panics if a value is Set with one type and then accessed with a different
+// expected type.
+type Config map[pkey.Key]any
+
+var _ policyclient.Client = Config{}
+
+func (c *Config) Set(key pkey.Key, value any) {
+	if *c == nil {
+		*c = make(map[pkey.Key]any)
+	}
+	(*c)[key] = value
+}
+
+func (c Config) GetStringArray(key pkey.Key, defaultVal []string) ([]string, error) {
+	if val, ok := c[key]; ok {
+		if arr, ok := val.([]string); ok {
+			return arr, nil
+		}
+		panic(fmt.Sprintf("key %s is not a []string", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetString(key pkey.Key, defaultVal string) (string, error) {
+	if val, ok := c[key]; ok {
+		if str, ok := val.(string); ok {
+			return str, nil
+		}
+		panic(fmt.Sprintf("key %s is not a string", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetBoolean(key pkey.Key, defaultVal bool) (bool, error) {
+	if val, ok := c[key]; ok {
+		if b, ok := val.(bool); ok {
+			return b, nil
+		}
+		panic(fmt.Sprintf("key %s is not a bool", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetUint64(key pkey.Key, defaultVal uint64) (uint64, error) {
+	if val, ok := c[key]; ok {
+		if u, ok := val.(uint64); ok {
+			return u, nil
+		}
+		panic(fmt.Sprintf("key %s is not a uint64", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetDuration(key pkey.Key, defaultVal time.Duration) (time.Duration, error) {
+	if val, ok := c[key]; ok {
+		if d, ok := val.(time.Duration); ok {
+			return d, nil
+		}
+		panic(fmt.Sprintf("key %s is not a time.Duration", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetPreferenceOption(key pkey.Key, defaultVal ptype.PreferenceOption) (ptype.PreferenceOption, error) {
+	if val, ok := c[key]; ok {
+		if p, ok := val.(ptype.PreferenceOption); ok {
+			return p, nil
+		}
+		panic(fmt.Sprintf("key %s is not a ptype.PreferenceOption", key))
+	}
+	return defaultVal, nil
+}
+
+func (c Config) GetVisibility(key pkey.Key) (ptype.Visibility, error) {
+	if val, ok := c[key]; ok {
+		if p, ok := val.(ptype.Visibility); ok {
+			return p, nil
+		}
+		panic(fmt.Sprintf("key %s is not a ptype.Visibility", key))
+	}
+	return ptype.Visibility(ptype.ShowChoiceByPolicy), nil
+}
+
+func (c Config) HasAnyOf(keys ...pkey.Key) (bool, error) {
+	for _, key := range keys {
+		if _, ok := c[key]; ok {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
+func (sp Config) RegisterChangeCallback(callback func(policyclient.PolicyChange)) (func(), error) {
+	return func() {}, nil
+}
+
+func (sp Config) SetDebugLoggingEnabled(enabled bool) {}