Add runtime checks to prevent wrong handling of constructor

xhttp/xhttp.go

@@ -1,18 +1,28 @@
 package xhttp
 
 import (
+	"errors"
 	"net/http"
 )
 
 type Middleware func(m http.RoundTripper) http.RoundTripper
 
 // Use is wrapping up a RoundTripper with a set of middleware
 func Use(client *http.Client, middlewares ...Middleware) *http.Client {
+	if client == nil {
+		panic(errors.New("client is nil"))
+	}
+	if len(middlewares) == 0 {
+		panic(errors.New("middlewares is nil"))
+	}
 	if client.Transport == nil {
 		client.Transport = http.DefaultTransport
 	}
 	current := client.Transport
 	for _, middleware := range middlewares {
+		if middleware == nil {
+			panic(errors.New("middleware is nil"))
+		}
 		current = middleware(current)
 	}
 	client.Transport = current

xhttp/xhttp_test.go

@@ -55,3 +55,39 @@ func TestInjectMiddlware(t *testing.T) {
 		log.Fatal(err)
 	}
 }
+
+func TestPanicNilClient(t *testing.T) {
+	defer func() {
+		v := recover()
+		err := v.(error)
+		if err.Error() != "client is nil" {
+			t.Errorf("error message is bad (%v)", v)
+		}
+	}()
+
+	xhttp.Use(nil, nil)
+}
+
+func TestPanicNilMiddleware(t *testing.T) {
+	defer func() {
+		v := recover()
+		err := v.(error)
+		if err.Error() != "middleware is nil" {
+			t.Errorf("error message is bad (%v)", v)
+		}
+	}()
+
+	xhttp.Use(new(http.Client), nil)
+}
+
+func TestPanicNilMiddlewares(t *testing.T) {
+	defer func() {
+		v := recover()
+		err := v.(error)
+		if err.Error() != "middlewares is nil" {
+			t.Errorf("error message is bad (%v)", v)
+		}
+	}()
+
+	xhttp.Use(new(http.Client))
+}