ROR syntax error in testing

I am newbie to ROR and working on a project which provides web services to a game. I have to write the test cases for that services.

How I can case against each model and controller case.

I wrote the following to create a new user in db

    test "create" do
    post(:create,
            {
                player:{
                    'player_name' => "usman", 
                    'password' => 123, 
                    'email' => 'ranasaani@gmail.com'
                }
            }
        )
    assert_select reponse.body

Controller code is

def create player = Player.create(params['player'])

if player.valid?
  # if creation successful, log the player in:
  player_session = PlayerSession.create(
    player: player,
    session_token: ActiveSupport::SecureRandom.urlsafe_base64
  )

  render json: {session_token: player_session.session_token}
else
  render json: {error: "Player name already exists."}, status: :unprocessable_entity
end

end

But there is an error

SyntaxError: xxx/players_controller_test.rb:5: syntax error, unexpected ':'
post(:create, {'player':{'player_name' => "usman", 'password' => 123, 'email' => 'ranasaani@gmail.com'}})

Is there any guide, how to write the test cases ?

I'm not commenting on your testing methods but in most cases of your code examples, the syntax is more like JSON instead of ruby hashes. Use :player => { :player_name => "usman", ... }. You can either use strings 'player' or ruby symbols :player as keys.

A more complete example with your render call:

render :json => {:error => "Player name already exists."}, :status => :unprocessable_entity

Ruby will convert the hash to JSON itself. Or you can do it manually by calling .to_json on it.