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Elixir & Phoenix: Scalable Backend Development · Lección

Pruebas de integración de aplicaciones Phoenix

Pruebe sus controladores, vistas y canales de Phoenix para garantizar que las distintas partes de su aplicación web funcionen conjuntamente.

Pruebas de integración de aplicaciones Phoenix es una lección gratuita de Elixir & Phoenix: Scalable Backend Development en CoddyKit. Esta es la lección 2 de 4. Puedes leer la lección completa abajo gratuitamente — luego la practicas en el navegador con un editor de código integrado y un tutor de IA 24/7. Forma parte de la ruta de aprendizaje de Elixir & Phoenix: Scalable Backend Development, y tu progreso se sincroniza en la web y la app de CoddyKit. El curso de Elixir & Phoenix: Scalable Backend Development incluye 4 lecciones en total.

Partes de esta lección aún no han sido traducidas y se muestran en inglés.

Test Web App Interactions

Welcome to integration testing for Phoenix applications! While unit tests check individual components, integration tests ensure different parts of your web application work together seamlessly.

  • They simulate real user interactions.
  • They cover routes, controllers, views, and channels.
  • They build confidence that your app's main flows function correctly.

Simulating HTTP Requests

Phoenix.ConnTest is your primary tool for testing HTTP requests. It allows you to simulate requests (GET, POST, PUT, DELETE) to your Phoenix application without needing a live server.

We use functions like get/2, post/3, and put/3 to send requests and then assert on the resulting connection (conn).

defmodule MyPhoenixAppWeb.ExampleTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume a simple router route: get "/hello", PageController, :hello
  # and PageController.hello renders a page with "Hello World"
  test "can get a simple page" do
    # Simulate a GET request to /hello
    conn = get("/hello")

    # Assert the HTTP status code
    assert conn.status == 200

    # Assert the response body contains "Hello World"
    assert html_response(conn, 200) =~ "Hello World"
  end
end

Testing GET Requests

GET requests are typically used to fetch data or display pages. When testing, you'll simulate the request and then assert on the response's status code and its content.

Use html_response/2 to extract the HTML body and assert against its content using pattern matching (=~).

defmodule MyPhoenixAppWeb.PostControllerTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume we have a router route: get "/posts", PostController, :index
  # And PostController.index renders a list of posts including "My First Post"
  test "lists all posts on GET /posts" do
    # Simulate a request to the /posts endpoint
    conn = get("/posts")

    # Assert that the request was successful and contains expected content
    assert conn.status == 200
    assert html_response(conn, 200) =~ "<h1>All Posts</h1>"
    assert html_response(conn, 200) =~ "My First Post"
  end
end

Testing POST Requests

POST requests are often used for creating new resources or submitting form data. When testing, you'll pass parameters along with the request.

After a successful creation, controllers often redirect. Use redirected_to/1 to check the redirect path.

defmodule MyPhoenixAppWeb.PostControllerTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume we have a router route: post "/posts", PostController, :create
  # This action creates a post and redirects to the index page.
  test "creates a new post on POST /posts" do
    post_params = %{"post" => %{"title" => "New Post", "body" => "Content"}}

    # Simulate a POST request with parameters
    conn = post("/posts", post_params)

    # Assert that a redirect occurred to the posts index
    assert redirected_to(conn) == "/posts"
  end
end

Asserting Rendered Content

It's crucial to verify that your views render the correct data and structure. html_response/2 allows you to get the rendered HTML as a string.

You can then use string assertions or regular expressions to check for specific text, HTML tags, or dynamic content.

defmodule MyPhoenixAppWeb.PageControllerTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume get "/dashboard" renders a page with user information
  test "renders dashboard with user info" do
    # For this example, we simulate a simple GET (no session handling here)
    conn = get("/dashboard")

    assert conn.status == 200
    response_html = html_response(conn, 200)

    # Check for specific elements in the rendered HTML
    assert response_html =~ "<title>Dashboard</title>"
    assert response_html =~ "<span>Welcome, John Doe!</span>"
    assert response_html =~ ~r/Last Login: \d{4}-\d{2}-\d{2}/ # Regex for dynamic date
  end
end

Testing Redirects and Errors

Testing user flow is vital. Phoenix provides helpers to assert redirects and error responses:

  • assert_redirected_to(conn, path): Verifies a redirect to a specific path.
  • assert_error_sent(conn, status): Checks for an HTTP error status code.
  • json_response(conn, status): Extracts a JSON body from an API error.
defmodule MyPhoenixAppWeb.AuthControllerTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume post "/login" redirects to /dashboard on success
  test "redirects after successful login" do
    login_params = %{"email" => "test@example.com", "password" => "password"}
    conn = post("/login", login_params)
    assert redirected_to(conn) == "/dashboard"
  end

  # Assume post "/register" sends a 400 error for invalid data
  test "sends 400 error for invalid registration" do
    invalid_params = %{"email" => "bad", "password" => "short"}
    conn = post("/register", invalid_params)
    assert conn.status == 400
    assert json_response(conn, 400) == %{"errors" => %{"email" => ["is invalid"]}}
  end
end

Simulating User Sessions

Many web applications rely on sessions to maintain state, like a logged-in user. In tests, you can manually manipulate the connection's session to simulate different user states.

Use build_conn/0 to create a fresh connection, then put_session/3 to add session data before making your request.

defmodule MyPhoenixAppWeb.SessionControllerTest do
  use ExUnit.Case, async: true
  import Phoenix.ConnTest

  # Assume get "/profile" requires a user_id in the session
  test "accesses profile with session data" do
    # Build a connection and add a user_id to its session
    conn = 
      build_conn()
      |> put_session(:user_id, 123)
      |> get("/profile")

    assert conn.status == 200
    assert html_response(conn, 200) =~ "User Profile for ID: 123"
  end

  test "redirects unauthenticated users" do
    # No session data means no authenticated user
    conn = get("/profile")
    assert redirected_to(conn) == "/login"
  end
end

Channel Testing Introduction

Phoenix Channels are for real-time communication using WebSockets. Integration tests for channels verify that clients can connect, join topics, send messages, and receive broadcasts correctly.

This is crucial for chat applications, live dashboards, and any feature requiring instant updates.

Connecting to a Channel

Phoenix.ChannelTest provides functions to simulate a client connecting to your WebSocket and joining specific channel topics. The main function you'll use is subscribe_and_join/3.

It returns {:ok, pid, socket}, where socket represents the client's connection to the channel.

defmodule MyPhoenixAppWeb.ChatChannelTest do
  use ExUnit.Case, async: true
  use Phoenix.ChannelTest

  # Assume MyPhoenixAppWeb.UserSocket is your main WebSocket module
  # and it handles joining a "room:lobby" channel.
  test "can join the lobby channel" do
    # Simulate a client connecting and joining "room:lobby" with no params
    {:ok, _pid, socket} = subscribe_and_join(MyPhoenixAppWeb.UserSocket, "room:lobby", %{})

    # Assert that the socket is connected to the correct topic
    assert socket.topic == "room:lobby"

    # You might also assert on assigns set during the join process
    # assert socket.assigns.user_id # If user_id is assigned on join
  end
end

Sending & Receiving Channel Messages

Once connected to a channel, you can test the message flow. Use push/3 to simulate a client sending a message to the server, and assert_broadcast/2 to verify that the server broadcasts messages back to the topic.

assert_reply/3 can check replies to specific client pushes.

defmodule MyPhoenixAppWeb.ChatChannelTest do
  use ExUnit.Case, async: true
  use Phoenix.ChannelTest

  # Assume MyPhoenixAppWeb.UserSocket handles "new_msg" events on "room:lobby"
  test "broadcasts messages to the lobby" do
    {:ok, _pid, socket} = subscribe_and_join(MyPhoenixAppWeb.UserSocket, "room:lobby", %{})

    # Simulate pushing a message from the client
    ref = push(socket, "new_msg", %{"body" => "Hello everyone!"})

    # Assert that the server replied 'ok' to the push
    assert_reply ref, :ok

    # Assert that a message was broadcasted back to the topic
    assert_broadcast "new_msg", %{"body" => "Hello everyone!"}
  end
end

Quick Check

Let's check your understanding of integration testing in Phoenix.

Recap: Integrated Confidence

You've learned how to write robust integration tests for your Phoenix applications!

  • We covered simulating HTTP requests using Phoenix.ConnTest.
  • You now know how to test GET and POST requests, assert rendered HTML, and verify redirects and errors.
  • We also explored testing real-time features with Phoenix.ChannelTest, simulating client connections and message flows.

By writing these tests, you gain confidence that your application's components work together as intended, leading to more stable and reliable web services!

Preguntas frecuentes

¿La lección «Pruebas de integración de aplicaciones Phoenix» es gratis?

Sí — el texto completo de «Pruebas de integración de aplicaciones Phoenix» es gratis para leer aquí en la web. Para practicarla de forma interactiva (editor de código integrado y tutor de IA 24/7) y desbloquear el resto del curso de Elixir & Phoenix: Scalable Backend Development, actualiza a CoddyKit PRO. El curso de Elixir & Phoenix: Scalable Backend Development incluye 4 lecciones en total.

¿Qué aprenderé en «Pruebas de integración de aplicaciones Phoenix»?

Pruebe sus controladores, vistas y canales de Phoenix para garantizar que las distintas partes de su aplicación web funcionen conjuntamente. Practicas Elixir & Phoenix: Scalable Backend Development con código real que ejecutas directamente en el navegador, y un tutor de IA 24/7 responde tus preguntas mientras trabajas en la lección.

¿Necesito experiencia previa para empezar Elixir & Phoenix: Scalable Backend Development?

No se requiere experiencia previa. Elixir & Phoenix: Scalable Backend Development en CoddyKit está estructurado para principiantes hasta estudiantes avanzados, así que puedes empezar aquí o desde el inicio y avanzar a tu ritmo. Esta es la lección 2 de 4.

¿Cuánto tiempo toma la lección «Pruebas de integración de aplicaciones Phoenix»?

La mayoría de las lecciones de CoddyKit toman alrededor de 5–10 minutos. Cada una es compacta e interactiva, así que avanzas constantemente y retomas exactamente por donde dejaste en la web y la app.

¿Puedo escribir y ejecutar código en esta lección de Elixir & Phoenix: Scalable Backend Development?

Sí. Cada lección de Elixir & Phoenix: Scalable Backend Development incluye un editor de código integrado, así que escribes y ejecutas código real directamente en tu navegador y obtienes retroalimentación instantánea de IA — sin configuración local necesaria.

Todas las lecciones de este curso

  1. Pruebas unitarias con ExUnit
  2. Pruebas de integración de aplicaciones Phoenix
  3. Mocks, stubs y datos de prueba
  4. Pruebas basadas en propiedades con StreamData
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