refactor: unify MockUserLookup into shared test helper package. Closes #439.

commands/add_test.go

@@ -17,33 +17,19 @@
 package commands
 
 import (
-	"os/user"
 	"testing"
 
 	"github.com/openpubkey/opkssh/policy"
 	"github.com/openpubkey/opkssh/policy/files"
+	"github.com/openpubkey/opkssh/test/testutil"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
 )
 
-// Duplicates code from multipolicyloader_test.go
-type MockUserLookup struct {
-	// User is returned on any call to Lookup() if Error is nil
-	User *user.User
-	// Error is returned on any call to Lookup() if non-nil
-	Error error
-}
-
-// Lookup implements policy.UserLookup
-func (m *MockUserLookup) Lookup(username string) (*user.User, error) {
-	if m.Error == nil {
-		return m.User, nil
-	} else {
-		return nil, m.Error
-	}
-}
+// MockUserLookup is an alias for testutil.MockUserLookup to keep test code concise.
+type MockUserLookup = testutil.MockUserLookup
 
-var ValidUser *user.User = &user.User{HomeDir: "/home/foo", Username: "foo"}
+var ValidUser = testutil.ValidUser
 
 func MockAddCmd(mockFs afero.Fs) *AddCmd {
 	mockUserLookup := &MockUserLookup{User: ValidUser}

policy/policyloader_test.go

@@ -25,27 +25,13 @@ import (
 
 	"github.com/openpubkey/opkssh/policy"
 	"github.com/openpubkey/opkssh/policy/files"
+	"github.com/openpubkey/opkssh/test/testutil"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
 )
 
-type MockUserLookup struct {
-	// User is returned on any call to Lookup() if Error is nil
-	User *user.User
-	// Error is returned on any call to Lookup() if non-nil
-	Error error
-}
-
-var _ policy.UserLookup = &MockUserLookup{}
-
-// Lookup implements policy.UserLookup
-func (m *MockUserLookup) Lookup(username string) (*user.User, error) {
-	if m.Error == nil {
-		return m.User, nil
-	} else {
-		return nil, m.Error
-	}
-}
+// MockUserLookup is an alias for testutil.MockUserLookup to keep test code concise.
+type MockUserLookup = testutil.MockUserLookup
 
 // MockFsOpenError embeds an afero.MemMapFs (implements afero.Fs) but allows for
 // finer control on when an error should be returned on a specific filepath
@@ -96,7 +82,7 @@ func NewTestSystemPolicyLoader(fs afero.Fs, userLookup policy.UserLookup) *polic
 	}
 }
 
-var ValidUser *user.User = &user.User{HomeDir: "/home/foo", Username: "foo"}
+var ValidUser = testutil.ValidUser
 
 func TestLoadUserPolicy_FailUserLookup(t *testing.T) {
 	// Test that LoadUserPolicy returns an error when user lookup fails

test/testutil/mockuserlookup.go

@@ -0,0 +1,50 @@
+// Copyright 2026 OpenPubkey
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package testutil
+
+import (
+	"fmt"
+	"os/user"
+
+	"github.com/openpubkey/opkssh/policy"
+)
+
+// ValidUser is a shared test fixture representing a valid OS user.
+var ValidUser = &user.User{HomeDir: "/home/foo", Username: "foo"}
+
+// MockUserLookup implements [policy.UserLookup] for testing.
+//   - Set [User] for a default user returned on any Lookup call.
+//   - Set [Error] to force every Lookup call to fail.
+type MockUserLookup struct {
+	// User is returned on any call to Lookup() if Error is nil.
+	User *user.User
+	// Error, if non-nil, is returned on any call to Lookup().
+	Error error
+}
+
+var _ policy.UserLookup = &MockUserLookup{}
+
+// Lookup implements [policy.UserLookup].
+func (m *MockUserLookup) Lookup(username string) (*user.User, error) {
+	if m.Error != nil {
+		return nil, m.Error
+	}
+	if m.User != nil {
+		return m.User, nil
+	}
+	return nil, fmt.Errorf("user %q not found", username)
+}