Add the client request check tests

Signed-off-by: JmPotato <[email protected]>

client/http/client.go

@@ -219,8 +219,8 @@ func (c *client) execDuration(name string, duration time.Duration) {
 
 // Header key definition constants.
 const (
-	PDAllowFollowerHandleKey = "PD-Allow-Follower-Handle"
-	ComponentSignatureKey    = "component"
+	pdAllowFollowerHandleKey = "PD-Allow-Follower-Handle"
+	componentSignatureKey    = "component"
 )
 
 // HeaderOption configures the HTTP header.
@@ -229,7 +229,7 @@ type HeaderOption func(header http.Header)
 // WithAllowFollowerHandle sets the header field to allow a PD follower to handle this request.
 func WithAllowFollowerHandle() HeaderOption {
 	return func(header http.Header) {
-		header.Set("PD-Allow-Follower-Handle", "true")
+		header.Set(pdAllowFollowerHandleKey, "true")
 	}
 }
 
@@ -278,7 +278,7 @@ func (c *client) request(
 	for _, opt := range headerOpts {
 		opt(req.Header)
 	}
-	req.Header.Set(ComponentSignatureKey, c.callerID)
+	req.Header.Set(componentSignatureKey, c.callerID)
 
 	start := time.Now()
 	resp, err := c.inner.cli.Do(req)

client/http/client_test.go

@@ -0,0 +1,73 @@
+// Copyright 2023 TiKV Project Authors.
+//
+// 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.
+
+package http
+
+import (
+	"context"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// requestChecker is used to check the HTTP request sent by the client.
+type requestChecker struct {
+	checker func(req *http.Request) error
+}
+
+// RoundTrip implements the `http.RoundTripper` interface.
+func (rc *requestChecker) RoundTrip(req *http.Request) (resp *http.Response, err error) {
+	return &http.Response{StatusCode: http.StatusOK}, rc.checker(req)
+}
+
+func newHTTPClientWithRequestChecker(checker func(req *http.Request) error) *http.Client {
+	return &http.Client{
+		Transport: &requestChecker{checker: checker},
+	}
+}
+
+func TestPDAllowFollowerHandleHeader(t *testing.T) {
+	re := require.New(t)
+	var exceptedVal string
+	httpClient := newHTTPClientWithRequestChecker(func(req *http.Request) error {
+		val := req.Header.Get(pdAllowFollowerHandleKey)
+		if val != exceptedVal {
+			re.Failf("PD allow follower handler header check failed",
+				"should be %s, but got %s", exceptedVal, val)
+		}
+		return nil
+	})
+	c := NewClient([]string{"http://127.0.0.1"}, WithHTTPClient(httpClient))
+	c.GetRegions(context.Background())
+	exceptedVal = "true"
+	c.GetHistoryHotRegions(context.Background(), &HistoryHotRegionsRequest{})
+}
+
+func TestCallerID(t *testing.T) {
+	re := require.New(t)
+	var exceptedVal string
+	httpClient := newHTTPClientWithRequestChecker(func(req *http.Request) error {
+		val := req.Header.Get(componentSignatureKey)
+		if val != exceptedVal {
+			re.Failf("Caller ID header check failed",
+				"should be %s, but got %s", exceptedVal, val)
+		}
+		return nil
+	})
+	c := NewClient([]string{"http://127.0.0.1"}, WithHTTPClient(httpClient))
+	c.GetRegions(context.Background())
+	exceptedVal = "test"
+	c.WithCallerID(exceptedVal).GetRegions(context.Background())
+}