Gain insights into building real-time web apps with Phoenix LiveView. Learn about creating interactive code, building a game from scratch, and managing distributed real-time dashboards.

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liveview.tar.gz

Installation

LiveView_Sockets

Simple_App

Wrong_Guess_Number

Plug_Conn

Wrong_Guess_Number-auth

Wrong_Guess_Number-auth-gen

Wrong_Guess_Number-auth-gen-final

Generator

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Generator-ected

Generator-web-ected

Forms-ected

Forms

Stateless

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Stateful

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Dashboard

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Distributed_Dashboard

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Unit_Test

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Core-ected

Core

phoenix_start_server

phoenix_build_only

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phoenix_build_intro

test

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intro_build_server

auth_build_server

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generate_web_build_ected

generate_web_build_server

generator_build_server

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forms_build_server

setup

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interactive_build_server

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distributed_build_server

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stateless_build_server

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stateful_build_server

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test_build_server

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core_build_server

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graphics_build_server

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test_build_server-chrome-fix

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intro-tester

If you want to program just for the joy of creating, LiveView will be an excellent opportunity for you. This programming model keeps your brain firmly on the server and lets you explore one concept at a time. Layering on graphics makes this kind of exploratory programming almost magical.

Programmers learn by writing code, and that’s exactly how this course will work. We’ll work on a project together as if we’re a fictional game company. You’ll write lots of code, starting with small tweaks of generated code and building up to major enhancements that extract common features with components.

As you build the application, you’ll encounter more complexity. A distributed dashboard will show a real-time view of other users and processes. You’ll even build a game from scratch—because that’s the best way to learn how to layer the most sophisticated LiveView applications.

Building Real-Time Web Applications with Phoenix LiveView

# Why testing is important

Think of a test as a scientific experiment. The experiment's target is a bit of code, and the thesis is that the code is working. Logically, each test is an experiment that does three things:
- Sets up preconditions
- Provides a stimulus
- Compares an actual response to expectations

That definition is pretty broad and covers a wide range of testing strategies and frameworks. We're going to write three tests of two specific types. Both types of tests will follow this broad pattern. One of the tests will be a **unit test**. We'll write it to verify the behavior of the independent functions that set up the socket. We’ll also write two **integration tests** that will let us verify the interaction between components:  one to test interactions *within* a LiveView process and another to verify interactions *between* processes.

The integration tests we write will interact with LiveView machinery to examine the impact of page loads and events that flow through a LiveView. A good example of such a test is simulating a button click and checking the impact on the re-rendered LiveView template. Integration tests have the benefit of catching **integration problems**—problems that occur at the integration points between different pieces of your system, in this case, the client and the server.

These integration tests are certainly valuable, but they can be brittle. For example, if the user interface changes the button into a link, your test must be updated. That means this type of test is costly in terms of long-term maintenance. Sometimes it pays to isolate specific functions with complex behavior—like our LiveView reducer functions—and write pure tests for them. Such tests are called unit tests because they test one specific unit of functionality. Let's discuss a testing strategy that addresses both integrated and isolated tests.

# Isolation Vs. Integration

Pure unit tests call one function at a time and then check expectations with one or more assertions. If you've designed your code well, you should find lots of opportunities for unit tests. By filling up your application's functional core with pure, predictable functions and by adhering to the CRC pattern, you'll find yourself with many small, isolated functions that can be tested with small, isolated unit tests, as follows.

Learn how testing should be done in a Phoenix application.

What Makes CRC Code Testable?

Introduction

Phoenix and Authentication

Generators: Contexts and Schemas

Generators: Live Views and Templates

Forms and Changesets

Stateless Components

Stateful Components

Build an Interactive Dashboard

Build a Distributed Dashboard

Test Your Live Views

Build The Game Core

Render Graphics With SVG

Conclusion

What Makes CRC Code Testable?

Why testing is important