diff --git a/instance_test.go b/instance_test.go
new file mode 100644
index 0000000..6724b53
--- /dev/null
+++ b/instance_test.go
@@ -0,0 +1,40 @@
+package mastodon
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestGetInstance(t *testing.T) {
+	canErr := true
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if canErr {
+			canErr = false
+			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+			return
+		}
+		fmt.Fprintln(w, `{"title": "mastodon"}`)
+	}))
+	defer ts.Close()
+
+	client := NewClient(&Config{
+		Server:       ts.URL,
+		ClientID:     "foo",
+		ClientSecret: "bar",
+		AccessToken:  "zoo",
+	})
+	_, err := client.GetInstance(context.Background())
+	if err == nil {
+		t.Fatalf("should be fail: %v", err)
+	}
+	ins, err := client.GetInstance(context.Background())
+	if err != nil {
+		t.Fatalf("should not be fail: %v", err)
+	}
+	if ins.Title != "mastodon" {
+		t.Fatalf("want %q but %q", "mastodon", ins.Title)
+	}
+}