Better Rspec tests with shared examples

TIL about shared examples in Rspec!

They’re primarily good for reducing duplicate code.

They work well with subject and let.

This is a made up example:

describe "Todos" do
  context 'when on the edit page' do
    subject { Todo.create(title: "Day 1", body: "Hello, World!") }
    let(:path) { edit_todo_path(subject) }

    it "displays form" do
      visit path

      expect(page).to have_css("form")
    end
    
    it "redirects after submitting update form" do
      visit path

      click_on "Update #{subject.class}"

      expect(page.current_url).not_to be path
    end
  end
end

You could write very similar tests for other models.

With shared examples you could do something like this:

shared_examples_for "Editing a resource" do
  it "displays form" do
    visit path
    expect(page).to have_css("form")
  end

  it "redirects after submitting update form" do
    visit path
    click_on "Update #{subject.class}"
    expect(page.current_url).not_to be path
  end
end

describe "Todos" do
  context 'when on the edit page' do
    subject { Todo.create(title: "Day 1", body: "Hello, World!") }
    let(:path) { edit_todo_path(subject) }

    it_behaves_like "Editing a resource"
  end
end

Then in the future when you need a test that does something similar, you can make/reference a a shared example group.

• Shared Examples
• RSpec(Pt. 2): Hooks, Subject, Shared Examples

DRY with dry_config gem

I was curious about how you could make gems have configuration settings (like from an initializer). I finally had a use case when writing appdev_support.

My goal was to be able to configure the gem like this:

# config/initializers/appdev_support.rb
AppdevSupport.config do |config|
  config.action_dispatch = true;
  config.active_record   = true;
end

and have these settings determine which class of method overrides should be loaded.

Previously, I was defining attr_writers like this

module AppdevSupport
  class << self
    attr_writer :active_record, :action_dispatch

    def action_dispatch
      @action_dispatch || true
    end

    def active_record
      @active_record || true
    end
  end
  # ...
end

Note to self, I still don’t really understand what class << self does or how it works (I think it makes a Singleton somehow?) but with that change I could dynamically load files by calling a class method:

   def self.init
    if @active_record
      load "appdev_support/active_record/delegation.rb"
      load "appdev_support/active_record/attribute_methods.rb"
      load "appdev_support/active_record/relation/to_s.rb"
    end
    if @action_dispatch
      load "appdev_support/action_dispatch/request/session/fetch.rb"
      load "appdev_support/action_dispatch/request/session/store.rb"
      load "appdev_support/action_dispatch/cookies/cookie_jar/fetch.rb"
      load "appdev_support/action_dispatch/cookies/cookie_jar/store.rb"
    end
  end

I wanted to make adding additional config settings easier to do and more seemless (like not having to run AppdevSupport.init if you just wanted the defaults).

TIL about the dry-configurable gem, which has been around for a while!

It really cleans up the “defining an instance variable/attr_writer” process and makes it a lot easier to define nested structures too!

require 'dry-configurable'

module App
  extend Dry::Configurable

  setting :api_url
  setting :repository, reader: true do
    # Can pass a default value
    setting :type, default: :local
    setting :encryption do
      setting :cipher, default: 'aes-256-cbc'
    end
  end
end

App.config.api_url = 'https://jelani.dev'
App.config.api_url # => 'https://jelani.dev'

This let me start to refactor the gem:

module AppdevSupport
  extend Dry::Configurable
  setting :active_record,   default: true
  setting :action_dispatch, default: true
  setting :pryrc,           default: :minimal
  # ...
end

While this was more concise and flexible, I still wasn’t able to get the defaults to load without calling AppdevSupport.init like before.

In searching for answers I found a post that taught me more responsible ways to define Monkeypatches and I incorperated some of those techniques into the gem as well.

• Configure anything with dry-configurable
• Use dry-configurable gem to add thread-safe configuration behaviour to your Ruby classes
• Responsible Monkeypatching in Ruby

Amending Git Commits

So one way or another, you hecked up and now GitHub says one user authored the commit while a different user committed the commit.

How to fix?

The only way I know is to amend or rebase, which will change commit Hashes and mess up other users commit History.

If you don’t care about that, proceed.

Change Committer

Pass GIT_COMMITTER_EMAIL and GIT_COMMITTER_NAME to amend with email and GitHub username respectively.

GIT_COMMITTER_EMAIL=joemama@example.com GIT_COMMITTER_NAME=joemama git commit --amend --no-edit

Change Author

Pass GIT_AUTHOR_EMAIL and GIT_AUTHOR_NAME to amend with email and namerespectively.

GIT_AUTHOR_EMAIL=joemama@example.com GIT_AUTHOR_NAME=joemama git commit --amend --no-edit

You can always find out the name by running git show ... on the commit that they made:

commit b65f3160e773ff2a18cc6e4993c278d50cedea94
Author: Joe Mama <joemama@example.com>
Date:   Thu Mar 2 11:55:40 2023 -0600

    Joe Mama's commit message 😎

Change Date

Useful if you editing several commits at once and want the origninal dates to not get updated to the current time.

Prepend GIT_COMMITTER_DATE env variable to your git ammend --no-edit command

GIT_COMMITTER_DATE="Wed Mar 29 20:32:01 2023 -0600" git commit --amend --no-edit --date="Wed Mar 29 20:32 2023 -0600"

--date will set the author date, which should also be the same as the committer date.

Amending a commit that’s not the most recent commit

You’ll need to rebase, git rebase -i HEAD~3 to edit the third most recent commit.

pick 93ef79f Dynamically resize textarea
pick cca2dd2 Display full titles on menu link hover
pick a372bc3 Use JS autosize for query field

You’ll want to choose edit for the commit you want to amend.

Note, if you only amend the author or committer for a past commit, all dates will be updated to current time.

If you want to keep the existing dates for these commits, it’s helpful to keep another Terminal tab open with the current git log and choose edit for each commit. Amend the author or committer for the desired commit and edit the date for the rest to be what the were before.

Reset primary key sequence SQLite3

I was trying to reset the primary key sequence in a development Rails environment and realized the usual:

ActiveRecord::Base.connection.reset_pk_sequence!('users')

did not work. (I think that is a postgres exclusive method)

I did some digging and found that executing this raw SQL did work:

ActiveRecord::Base.connection.execute("UPDATE SQLITE_SEQUENCE SET SEQ=0 WHERE NAME='table_name'")

I learned from this post.

Moving hidden files in the command line

I was attempting to move all files from a subfolder into the root folder in the command line and ran:

mv subfolder/* .

but to my surprise, files beginning with ., like .gitignore, did not move.

It turns out hidden files are exlcuded by default I guess?

If you want to move dotfiles, you can do this instead:

mv subfolder/{,.}* .

See this answer.