Bufconn Test

package main

import (
	"context"
	"net"
	"testing"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/status"
	"google.golang.org/grpc/test/bufconn"

	"shortener/pb"
)

func setupTest(t *testing.T) pb.LinkServiceClient {
	t.Helper()
	lis := bufconn.Listen(1024 * 1024)
	srv := grpc.NewServer()
	pb.RegisterLinkServiceServer(srv, newLinkServer())
	go srv.Serve(lis)
	t.Cleanup(func() { srv.Stop(); lis.Close() })

	conn, err := grpc.NewClient("passthrough:///bufconn",
		grpc.WithContextDialer(func(ctx context.Context, s string) (net.Conn, error) {
			return lis.DialContext(ctx)
		}),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
	)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { conn.Close() })
	return pb.NewLinkServiceClient(conn)
}

func TestCreateAndGet(t *testing.T) {
	client := setupTest(t)
	ctx := context.Background()

	created, err := client.CreateLink(ctx, &pb.CreateLinkRequest{Url: "https://test.com"})
	if err != nil {
		t.Fatal(err)
	}

	fetched, err := client.GetLink(ctx, &pb.GetLinkRequest{ShortCode: created.GetLink().GetShortCode()})
	if err != nil {
		t.Fatal(err)
	}
	if fetched.GetLink().GetUrl() != "https://test.com" {
		t.Errorf("got %q, want %q", fetched.GetLink().GetUrl(), "https://test.com")
	}
}

func TestGetNotFound(t *testing.T) {
	client := setupTest(t)
	_, err := client.GetLink(context.Background(), &pb.GetLinkRequest{ShortCode: "nope"})
	st, _ := status.FromError(err)
	if st.Code() != codes.NotFound {
		t.Errorf("got %v, want NotFound", st.Code())
	}
}