fix: (#1410)

1. the length of trailer key should > 0
2. fix http_test words typo

header.go

@@ -2520,8 +2520,8 @@ func (h *ResponseHeader) parseTrailer(buf []byte) (int, error) {
 				err = fmt.Errorf("forbidden trailer key %q", s.key)
 				continue
 			}
+			h.h = appendArgBytes(h.h, s.key, s.value, argsHasValue)
 		}
-		h.h = appendArgBytes(h.h, s.key, s.value, argsHasValue)
 	}
 	if s.err != nil {
 		return 0, s.err

http_test.go

@@ -1660,10 +1660,10 @@ func TestRequestReadLimitBody(t *testing.T) {
 }
 
 func testResponseReadLimitBodyError(t *testing.T, s string, maxBodySize int, expectedErr error) {
-	var req Response
+	var resp Response
 	r := bytes.NewBufferString(s)
 	br := bufio.NewReader(r)
-	err := req.ReadLimitBody(br, maxBodySize)
+	err := resp.ReadLimitBody(br, maxBodySize)
 	if err == nil {
 		t.Fatalf("expecting error. s=%q, maxBodySize=%d", s, maxBodySize)
 	}
@@ -1673,10 +1673,10 @@ func testResponseReadLimitBodyError(t *testing.T, s string, maxBodySize int, exp
 }
 
 func testResponseReadLimitBodySuccess(t *testing.T, s string, maxBodySize int) {
-	var req Response
+	var resp Response
 	r := bytes.NewBufferString(s)
 	br := bufio.NewReader(r)
-	if err := req.ReadLimitBody(br, maxBodySize); err != nil {
+	if err := resp.ReadLimitBody(br, maxBodySize); err != nil {
 		t.Fatalf("unexpected error: %v. s=%q, maxBodySize=%d", err, s, maxBodySize)
 	}
 }