diff --git a/pkg/testttp/http.go b/pkg/testttp/http.go
index 0164c933bc..05e4e408b6 100644
--- a/pkg/testttp/http.go
+++ b/pkg/testttp/http.go
@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"net/http/httptest"
+	"net/url"
 	"testing"
 )
 
@@ -79,6 +80,14 @@ func (r *Req) Do(handler http.Handler) *Resp {
 	}
 }
 
+func (r *Req) SetFormValue(k, v string) *Req {
+	if r.req.Form == nil {
+		r.req.Form = make(url.Values)
+	}
+	r.req.Form.Set(k, v)
+	return r
+}
+
 // Headers allows the user to set headers on the http request.
 func (r *Req) Headers(k, v string, rest ...string) *Req {
 	headers := append(rest, k, v)
diff --git a/pkg/testttp/http_test.go b/pkg/testttp/http_test.go
index ebb57d9da8..5bed499486 100644
--- a/pkg/testttp/http_test.go
+++ b/pkg/testttp/http_test.go
@@ -45,11 +45,33 @@ func TestHTTP(t *testing.T) {
 	})
 
 	t.Run("Post", func(t *testing.T) {
-		testttp.
-			Post(t, "/", nil).
-			Do(svr).
-			ExpectStatus(http.StatusCreated).
-			ExpectBody(assertBody(t, http.MethodPost))
+		t.Run("basic", func(t *testing.T) {
+			testttp.
+				Post(t, "/", nil).
+				Do(svr).
+				ExpectStatus(http.StatusCreated).
+				ExpectBody(assertBody(t, http.MethodPost))
+		})
+
+		t.Run("with form values", func(t *testing.T) {
+			svr := http.NewServeMux()
+			svr.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				r.ParseForm()
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte(r.FormValue("key")))
+			}))
+
+			testttp.
+				Post(t, "/", nil).
+				SetFormValue("key", "val").
+				Do(svr).
+				ExpectStatus(http.StatusOK).
+				ExpectBody(func(body *bytes.Buffer) {
+					if expected, got := "val", body.String(); expected != got {
+						t.Fatalf("did not get form value; expected=%q got=%q", expected, got)
+					}
+				})
+		})
 	})
 
 	t.Run("PostJSON", func(t *testing.T) {