add test for internal http client's Do() func

github/github_test.go

@@ -151,6 +151,28 @@ func TestDo_httpError(t *testing.T) {
 	}
 }
 
+// Test handling of an error caused by the internal http client's Do()
+// function.  A redirect loop is pretty unlikely to occur within the GitHub
+// API, but does allow us to exercise the right code path.
+func TestDo_redirectLoop(t *testing.T) {
+	setup()
+	defer teardown()
+
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, "/", http.StatusFound)
+	})
+
+	req, _ := client.NewRequest("GET", "/", nil)
+	_, err := client.Do(req, nil)
+
+	if err == nil {
+		t.Error("Expected error to be returned.")
+	}
+	if err, ok := err.(*url.Error); !ok {
+		t.Errorf("Expected a URL error; got %#v.", err)
+	}
+}
+
 func TestCheckResponse(t *testing.T) {
 	res := &http.Response{
 		Request:    &http.Request{},