diff --git a/state/remote/http_test.go b/state/remote/http_test.go
index 55d682d17..40765b8ee 100644
--- a/state/remote/http_test.go
+++ b/state/remote/http_test.go
@@ -14,6 +14,7 @@ import (
 
 func TestHTTPClient_impl(t *testing.T) {
 	var _ Client = new(HTTPClient)
+	var _ ClientLocker = new(HTTPClient)
 }
 
 func TestHTTPClient(t *testing.T) {
@@ -28,10 +29,15 @@ func TestHTTPClient(t *testing.T) {
 
 	client := &HTTPClient{URL: url, Client: cleanhttp.DefaultClient()}
 	testClient(t, client)
+
+	a := &HTTPClient{URL: url, Client: cleanhttp.DefaultClient(), SupportsLocking: true}
+	b := &HTTPClient{URL: url, Client: cleanhttp.DefaultClient(), SupportsLocking: true}
+	TestRemoteLocks(t, a, b)
 }
 
 type testHTTPHandler struct {
-	Data []byte
+	Data   []byte
+	Locked bool
 }
 
 func (h *testHTTPHandler) Handle(w http.ResponseWriter, r *http.Request) {
@@ -39,12 +45,25 @@ func (h *testHTTPHandler) Handle(w http.ResponseWriter, r *http.Request) {
 	case "GET":
 		w.Write(h.Data)
 	case "POST":
-		buf := new(bytes.Buffer)
-		if _, err := io.Copy(buf, r.Body); err != nil {
-			w.WriteHeader(500)
+		switch r.URL.Path {
+		case "/":
+			// state
+			buf := new(bytes.Buffer)
+			if _, err := io.Copy(buf, r.Body); err != nil {
+				w.WriteHeader(500)
+			}
+
+			h.Data = buf.Bytes()
+		case "/lock":
+			if h.Locked {
+				w.WriteHeader(409)
+			} else {
+				h.Locked = true
+			}
+		case "/unlock":
+			h.Locked = false
 		}
 
-		h.Data = buf.Bytes()
 	case "DELETE":
 		h.Data = nil
 		w.WriteHeader(200)