public async Task ById()
{
var options = new DbContextOptionsBuilder <ApplicationDbContext>()
.UseInMemoryDatabase(databaseName: "B_Database")
.Options;
var dbContext = new ApplicationDbContext(options);
var postService = new PostService(dbContext);
await postService.CreatePostAsync("Tweets", "Hello i am tweet", "u1", 1);
var post = await postService.ByIdAsync(1);
Assert.Equal(1, post.Id);
Assert.Equal("Tweets", post.Title);
Assert.Equal("Hello i am tweet", post.Content);
Assert.Equal("u1", post.UserId);
}