diff --git a/internal/context/context_test.go b/internal/context/context_test.go
new file mode 100644
index 000000000..563c8c694
--- /dev/null
+++ b/internal/context/context_test.go
@@ -0,0 +1,98 @@
+package context
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestContext(t *testing.T) {
+	ctx1 := context.WithValue(context.Background(), "go-kratos", "https://github.com/go-kratos/")
+	ctx2 := context.WithValue(context.Background(), "kratos", "https://go-kratos.dev/")
+
+	ctx, cancel := Merge(ctx1, ctx2)
+	defer cancel()
+
+	got := ctx.Value("go-kratos")
+	value1, ok := got.(string)
+	assert.Equal(t, ok, true)
+	assert.Equal(t, value1, "https://github.com/go-kratos/")
+	//
+	got2 := ctx.Value("kratos")
+	value2, ok := got2.(string)
+	assert.Equal(t, ok, true)
+	assert.Equal(t, value2, "https://go-kratos.dev/")
+
+	t.Log(value1)
+	t.Log(value2)
+}
+
+func TestErr(t *testing.T) {
+	ctx1, cancel := context.WithTimeout(context.Background(), time.Microsecond)
+	defer cancel()
+	time.Sleep(time.Millisecond)
+
+	ctx, cancel := Merge(ctx1, context.Background())
+	defer cancel()
+
+	assert.Equal(t, ctx.Err(), context.DeadlineExceeded)
+}
+
+func TestDone(t *testing.T) {
+	ctx1, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	ctx, cancel := Merge(ctx1, context.Background())
+	go func() {
+		time.Sleep(time.Millisecond * 50)
+		cancel()
+	}()
+
+	assert.Equal(t, <-ctx.Done(), struct{}{})
+}
+
+func TestFinish(t *testing.T) {
+	mc := &mergeCtx{
+		parent1:  context.Background(),
+		parent2:  context.Background(),
+		done:     make(chan struct{}),
+		cancelCh: make(chan struct{}),
+	}
+	err := mc.finish(context.DeadlineExceeded)
+	assert.Equal(t, err, context.DeadlineExceeded)
+	assert.Equal(t, mc.doneMark, uint32(1))
+	assert.Equal(t, <-mc.done, struct{}{})
+}
+
+func TestWait(t *testing.T) {
+	ctx1, cancel := context.WithCancel(context.Background())
+
+	mc := &mergeCtx{
+		parent1:  ctx1,
+		parent2:  context.Background(),
+		done:     make(chan struct{}),
+		cancelCh: make(chan struct{}),
+	}
+	go func() {
+		time.Sleep(time.Millisecond * 50)
+		cancel()
+	}()
+
+	mc.wait()
+	t.Log(mc.doneErr)
+	assert.Equal(t, mc.doneErr, context.Canceled)
+}
+
+func TestCancel(t *testing.T) {
+	mc := &mergeCtx{
+		parent1:  context.Background(),
+		parent2:  context.Background(),
+		done:     make(chan struct{}),
+		cancelCh: make(chan struct{}),
+	}
+	mc.cancel()
+
+	assert.Equal(t, <-mc.cancelCh, struct{}{})
+}
diff --git a/metadata/metadata_test.go b/metadata/metadata_test.go
index 61a2ef36f..55439b16f 100644
--- a/metadata/metadata_test.go
+++ b/metadata/metadata_test.go
@@ -238,3 +238,48 @@ func TestMergeToClientContext(t *testing.T) {
 		})
 	}
 }
+
+func TestMetadata_Range(t *testing.T) {
+	md := Metadata{"kratos": "kratos", "https://go-kratos.dev/": "https://go-kratos.dev/", "go-kratos": "go-kratos"}
+	var tmp = Metadata{}
+	md.Range(func(k, v string) bool {
+		if k == "https://go-kratos.dev/" || k == "kratos" {
+			tmp[k] = v
+		}
+		return true
+	})
+	if !reflect.DeepEqual(tmp, Metadata{"https://go-kratos.dev/": "https://go-kratos.dev/", "kratos": "kratos"}) {
+		t.Errorf("metadata = %v, want %v", tmp, Metadata{"kratos": "kratos"})
+	}
+}
+
+func TestMetadata_Clone(t *testing.T) {
+	tests := []struct {
+		name string
+		m    Metadata
+		want Metadata
+	}{
+		{
+			name: "kratos",
+			m:    Metadata{"kratos": "kratos", "https://go-kratos.dev/": "https://go-kratos.dev/", "go-kratos": "go-kratos"},
+			want: Metadata{"kratos": "kratos", "https://go-kratos.dev/": "https://go-kratos.dev/", "go-kratos": "go-kratos"},
+		},
+		{
+			name: "go",
+			m:    Metadata{"language": "golang"},
+			want: Metadata{"language": "golang"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := tt.m.Clone()
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Clone() = %v, want %v", got, tt.want)
+			}
+			got["kratos"] = "go"
+			if reflect.DeepEqual(got, tt.want) {
+				t.Errorf("want got != want got %v want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/middleware/middleware_test.go b/middleware/middleware_test.go
new file mode 100644
index 000000000..ca5ff4c5a
--- /dev/null
+++ b/middleware/middleware_test.go
@@ -0,0 +1,54 @@
+package middleware
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var i int
+
+func TestChain(t *testing.T) {
+	next := func(ctx context.Context, req interface{}) (interface{}, error) {
+		t.Log(req)
+		i += 10
+		return "reply", nil
+	}
+
+	got, err := Chain(test1Middleware, test2Middleware, test3Middleware)(next)(context.Background(), "hello kratos!")
+	assert.Nil(t, err)
+	assert.Equal(t, got, "reply")
+	assert.Equal(t, i, 16)
+}
+
+func test1Middleware(handler Handler) Handler {
+	return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
+		fmt.Println("test1 before")
+		i++
+		reply, err = handler(ctx, req)
+		fmt.Println("test1 after")
+		return
+	}
+}
+
+func test2Middleware(handler Handler) Handler {
+	return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
+		fmt.Println("test2 before")
+		i += 2
+		reply, err = handler(ctx, req)
+		fmt.Println("test2 after")
+		return
+	}
+}
+
+func test3Middleware(handler Handler) Handler {
+	return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
+		fmt.Println("test3 before")
+		i += 3
+		reply, err = handler(ctx, req)
+		fmt.Println("test3 after")
+		return
+	}
+}