diff --git a/locale-helper/allow_caller.go b/locale-helper/allow_caller.go
index ddc3492..c0dc25c 100644
--- a/locale-helper/allow_caller.go
+++ b/locale-helper/allow_caller.go
@@ -57,7 +57,7 @@ type persistedCallerEntry struct {
 }
 
 type persistedAllowCallers struct {
-	BusID   string                `json:"busId"`
+	BusID   string                 `json:"busId"`
 	Callers []persistedCallerEntry `json:"callers"`
 }
 
@@ -71,6 +71,7 @@ type allowCallerRegistry struct {
 	stateFile         string
 	busID             string
 	privilegedGroupID uint32
+	processStartTime  func(uint32) (uint64, error)
 	processGroups     func(uint32) ([]uint32, error)
 	processParent     func(uint32) (uint32, error)
 
@@ -127,6 +128,7 @@ func newAllowCallerRegistryWithConfig(service allowCallerBus, stateFile string,
 		stateFile:         stateFile,
 		busID:             busID,
 		privilegedGroupID: privilegedGroupID,
+		processStartTime:  getProcessStartTime,
 		processGroups:     getProcessGroups,
 		processParent:     getProcessParentPID,
 		callers:           make(map[string]callerInfo),
@@ -336,7 +338,7 @@ func (r *allowCallerRegistry) authorizeRegistrar(sender dbus.Sender, uniqueName
 	}
 
 	// Capture starttime before reading /proc to detect PID reuse (TOCTOU mitigation).
-	senderStartTime, err := getProcessStartTime(senderPID)
+	senderStartTime, err := r.processStartTime(senderPID)
 	if err != nil {
 		return fmt.Errorf("get sender %s start time failed: %w", sender, err)
 	}
@@ -347,7 +349,7 @@ func (r *allowCallerRegistry) authorizeRegistrar(sender dbus.Sender, uniqueName
 	}
 
 	// Verify PID was not recycled during /proc access.
-	checkStartTime, err := getProcessStartTime(senderPID)
+	checkStartTime, err := r.processStartTime(senderPID)
 	if err != nil || checkStartTime != senderStartTime {
 		return fmt.Errorf("sender %s PID %d reused during authorization", sender, senderPID)
 	}
@@ -525,4 +527,4 @@ func (r *allowCallerRegistry) load() error {
 	}
 	r.mu.Unlock()
 	return nil
-}
\ No newline at end of file
+}
diff --git a/locale-helper/allow_caller_test.go b/locale-helper/allow_caller_test.go
index cc8cebc..e702baf 100644
--- a/locale-helper/allow_caller_test.go
+++ b/locale-helper/allow_caller_test.go
@@ -68,6 +68,9 @@ func newRegistryForTest(t *testing.T, bus *mockAllowCallerBus) *allowCallerRegis
 	require.NoError(t, err)
 	require.NotNil(t, r)
 	require.Equal(t, bus.busID, r.busID)
+	r.processStartTime = func(uint32) (uint64, error) {
+		return 1, nil
+	}
 	return r
 }
 
@@ -218,6 +221,7 @@ func TestNewAllowCallerRegistryWithConfig(t *testing.T) {
 		assert.Equal(t, uint32(42), r.privilegedGroupID)
 		assert.NotNil(t, r.callers)
 		assert.Len(t, r.callers, 0)
+		assert.NotNil(t, r.processStartTime)
 		assert.NotNil(t, r.processGroups)
 		assert.NotNil(t, r.processParent)
 	})
@@ -692,4 +696,4 @@ func TestLookupGroupID(t *testing.T) {
 	gid, err := lookupGroupID("root")
 	require.NoError(t, err)
 	assert.Equal(t, uint32(0), gid)
-}
\ No newline at end of file
+}