Property-Based Testing with PropEr in Elixir

Takeaway Skills

Understand the concepts of PropEr.

Understand the role of generators in property in property-based testing.

Have a clear sense where property-based testing has an advantage over Eunit tests and vice versa.

Be able to use stateful properties with ease.

Learn how to write State Machine Properties.

Understand property-based testing

Understand the concepts of PropEr.

Understand the role of generators in property in property-based testing.

Have a clear sense where property-based testing has an advantage over Eunit tests and vice versa.

Be able to use stateful properties with ease.

Learn how to write State Machine Properties.

Understand property-based testing

Course Overview

Property-based testing relies on specifying some property of code, unlike unit tests, which specify the expected output in response to some inputs. In this course, we'll cover the concepts we need to feel confident about using even the most advanced features of PropEr with Elixir. We'... See More

How You'll Learn

Hands-on coding environments

You don’t get better at swimming by watching others. Coding is no different. Practice as you learn with live code environments inside your browser.

Faster than videos

Videos are holding you back. The average video tutorial is spoken at 150 words per minute, while you can read at 250. That‘s why our courses are text-based.

No set-up required

Start learning immediately instead of fiddling with SDKs and IDEs. It‘s all on the cloud.

Progress you can show

Built in assessments let you test your skills. Completion certificates let you show them off.

Hands-on coding environments

You don’t get better at swimming by watching others. Coding is no different. Practice as you learn with live code environments inside your browser.

Faster than videos

Videos are holding you back. The average video tutorial is spoken at 150 words per minute, while you can read at 250. That‘s why our courses are text-based.

No set-up required

Start learning immediately instead of fiddling with SDKs and IDEs. It‘s all on the cloud.

Progress you can show

Built in assessments let you test your skills. Completion certificates let you show them off.

Course Contents

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1. Foundations of Property-Based Testing

Why Property-based Testing?

Properties

Property-Based Testing in a Project

Running a Property

Wrapping Up

2. Writing Properties

Introduction to Writing Properties

File Structure

Property Structure

Execution Model

Default Generators

Putting It All Together

Wrapping Up

Quiz Yourself on Writing Properties

3. Thinking in Properties

Introduction to Thinking in Properties

Modeling

Generalizing Test Examples

Invariants

Symmetric Properties

Putting It All Together

Wrapping Up

Quiz Yourself on Thinking in Properties

4. Custom Generators

Introduction to Custom Generators

Gathering Statistics: Collecting

Gathering Statistics: Aggregating

Basic Custom Generators

Resizing Generators

Transforming Generators

Imposing Restrictions

Changing Probabilities

Fancy Custom Generators

Recursive Generators

Symbolic Calls

Wrapping Up

Quiz Yourself on Custom Generators

5. Responsible Testing

Introduction to Responsible Testing

The Program Structure

CSV Parsing: The Property

CSV Parsing: The CSV Parser

Filtering Records

Employee Module

Templating

Putting It All Together

Wrapping Up

6. Properties-Driven Development

Introduction to Properties-driven Development

Writing the First Property

Testing Specials

Generating Specials

Implementing Specials

Negative Testing: Broad Properties

Negative Testing: Calibrating Negative Properties

Negative Testing: Relaxing Constraints

Wrapping Up

7. Shrinking

Introduction to Shrinking

Re-centering with shrink

Dividing with let_shrink

Wrapping Up

Quiz Yourself on Shrinking

8. Stateful Properties

Introduction to Stateful Properties

How Stateful Properties Run

Writing Stateful Properties

Testing a Basic Concurrent Cache: Implementation

Testing a Basic Concurrent Cache: Writing Tests

Testing Parallel Executions

Wrapping Up

Quiz Yourself on Stateful Properties

9. Case Study: Bookstore

Introducing the Application

The Application: Getting Started

The Application: The Database Module

The Application: Running the Code

Writing Generators

Broad Stateful Testing

Precise Stateful Modelling

Refining the Tests

Debugging Stateful Properties

Parallel Tests

Wrapping Up

10. State Machine Properties

Introduction to State Machine Properties

Laying Out State Machine Properties

How State Machine Properties Run

Writing FSM Properties

Testing a Circuit Breaker

Modeling the Circuit Breaker: The Shim Module

Modeling the Circuit Breaker: The Property

Modeling the Circuit Breaker: The Test Module

Adjusting the Model: Fixing the Issue

Adjusting the Model: Better Statistics

Wrapping Up

11. Conclusion

Conclusion