https://github.com/michaeljklein/nil-passer

Pass nils to single-arg blocks in Ruby on Rails for testing
https://github.com/michaeljklein/nil-passer

nil-passer rails ruby testing-tools

Last synced: 2 months ago
JSON representation

Pass nils to single-arg blocks in Ruby on Rails for testing

• Host: GitHub
• URL: https://github.com/michaeljklein/nil-passer
• Owner: michaeljklein
• License: mit
• Created: 2017-03-08T01:11:19.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2017-12-11T18:04:27.000Z (over 8 years ago)
• Last Synced: 2025-03-06T18:50:34.205Z (over 1 year ago)
• Topics: nil-passer, rails, ruby, testing-tools
• Language: Ruby
• Homepage: https://michaeljklein.github.io/nil-passer/
• Size: 86.9 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
# Nil-Passer 

## Status

[![Build Status](https://travis-ci.org/michaeljklein/nil-passer.svg?branch=master)](https://travis-ci.org/michaeljklein/nil-passer)

[![Maintainability](https://api.codeclimate.com/v1/badges/4723ba66092afa0a20e1/maintainability)](https://codeclimate.com/github/michaeljklein/nil-passer/maintainability)

[![Test Coverage](https://api.codeclimate.com/v1/badges/4723ba66092afa0a20e1/test_coverage)](https://codeclimate.com/github/michaeljklein/nil-passer/test_coverage)

[![Gem Version](https://badge.fury.io/rb/nil-passer.svg)](https://badge.fury.io/rb/nil-passer)

[![Codacy Badge](https://api.codacy.com/project/badge/Grade/8ec82f7c480c412587116366b89189bf)](https://www.codacy.com/app/michaeljklein/nil-passer?utm_source=github.com&utm_medium=referral&utm_content=michaeljklein/nil-passer&utm_campaign=Badge_Grade)

[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/nil-passer/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)

## Introduction

Ever been sick of blocks not handling nil in Ruby, or more specifically Rails?

This gem defines the [`NilPasser`](https://github.com/michaeljklein/nil-passer/blob/master/lib/nil_passer.rb#L3) class, which can be used to monitor all passing of blocks on an object, through a specific method, or to a class.

Each block passed is passed `nil` and the execution _usually_ continues normally. (Usually meaning you probably don't want to use this in production.)

During or after execution, you can `grep '^[no_nil]'` on your logs to get all the results.

Loosely inspired by the [`bullet`](https://github.com/flyerhzm/bullet) gem.

# Examples

From [the tests](https://github.com/michaeljklein/nil-passer/blob/master/test/test_nil_passer.rb), we have example usage for "good, bad, and subtle" blocks:

## Good

This is the control: we provide the caller's location and the identity (function) block ([source](https://github.com/michaeljklein/nil-passer/blob/master/test/test_nil_passer.rb#L45)):

```

  def test_test_ignores_good_block

    assert @log.blank?

    NilPasser.test [Rails.path], Proc.new{|x| x}

    assert @log.blank?

  end

```

## Bad

This is a simple exception-handling case, where the block accepts `nil` but always raises an exception ([source](https://github.com/michaeljklein/nil-passer/blob/master/test/test_nil_passer.rb#L51)):

```

  def test_test_catches_bad_block

    assert  @log.blank?

    NilPasser.test [Rails.path], Proc.new{|x| (raise "hi")}

    assert !@log.blank?

  end

```

## Subtle

This is an example of a block that _only_ raises an exception when passed `nil` ([source](https://github.com/michaeljklein/nil-passer/blob/master/test/test_nil_passer.rb#L57)):

```

  def test_test_catches_subtle_block

    assert  @log.blank?

    NilPasser.test [Rails.path], Proc.new{|x| x.nil? && (raise "hi")}

    assert !@log.blank?

  end

```