chore: add an integration test for IsNotFound (#6)

error_test.go

@@ -2,9 +2,12 @@
 package aiven
 
 import (
+	"context"
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestIsNotFound(t *testing.T) {
@@ -42,6 +45,22 @@ func TestIsNotFound(t *testing.T) {
 	}
 }
 
+func TestIsNotFoundIntegration(t *testing.T) {
+	token := os.Getenv("AIVEN_TOKEN")
+	if token == "" {
+		t.Skip("token is required for the test")
+	}
+
+	c, err := NewClient()
+	require.NoError(t, err)
+
+	ctx := context.Background()
+	out, err := c.AccountGet(ctx, "does_not_exist")
+	assert.Nil(t, out)
+	assert.NotNil(t, err)
+	assert.True(t, IsNotFound(err))
+}
+
 func TestIsAlreadyExists(t *testing.T) {
 	cases := []struct {
 		name   string