MySQL shell: Enable UTF-8

When you do a script/dbconsole -p, your MySQL shell will already be using UTF-8. When you call it yourself using mysql, it may not be enabled.

You'll notice that when you get ASCII salad and/or question marks instead of special characters. \
Example: Hlavn� m?sto Praha instead of Hlavní město Praha.

You need to manually switch on UTF-8, in the MySQL console:

SET NAMES 'utf8';

Capybara: Test that a string is visible as static text

This is surprisingly difficult when there is a <textarea> with the same text on the page, but you really want to see the letters as static text in a <p> or similiar.

The step definition below lets you say:

Then I should see the text "foo"

You should not look too closely at the step definition because when you see the light, it will blind you.

Then /^I should see the text "(.*?)"$/ do |text|
  elements = page.all('*', :text => text).reject { |element| element.tag_name == 'textarea' || element.all('*', :text => text...

Make your Rails console (and irb) output better readable

Pour color on your Rails console with awesome_print. Turn confusing long strings into formatted output. Have objects and classes laid out clearly whenever you need it.

Put gem 'awesome_print', :group => :development into your Gemfile. Now on the Rails console you have the command ap that will give you a colored, formatted output of whatever you pass it. See the example output of the User class below.

For customization visit the repository on Github.

![awesome_print.png](https://makan...

responsive.is

Online tool to test how a site behaves in popular desktop, tablet and phone resolutions.

Spec "content_for" calls in helpers

This only applies to RSpec below version 1.3.2. The issue has been fixed in RSpec 1.3.2, and most likely RSpec 2 and later versions.


When you have a helper that calls content_for and want to check its behavior you should probably write a feature instead. If you still want to do it, mind the following.

Consider this helper:

module LayoutHelper
  def title(string)
    content_for :title, string
    string
  end
end

Somewhere in the layout we'd then say something like this: `<%= yield :title %...</p>

Markdown/Commonmarker examples

This card shows you how to format a card's content using Markdown. We use the Commonmarker interpreter, so here are examples for its dialect.

Formatting

**Bold**

Bold

_Italics_

Italics

`Monospaced`

Monospaced

> Quoted text

Quoted text

Here is [a link](http://makandra.com/).

Here is a link.

![An image; this is the alt text](http:/...

Creating the inverse of a Rails migration

Let's say you need to revert a migration that happened a while back. You'd create a new migration that removes what was added back then in the up path, while its down path restores the old functionality.

While you could just copy&paste the down and up parts of it to the inverse part of the new migration, you may not want to do that. Especially when the up/down paths already contained some logic (that executed update statements on the created column, for example), copying does not feel right.

Someone already added the logic how to...

WebMock 1.8.0 does not play nice with Curb < 0.7.16

When updating WebMock, be prepared that your specs may send real requests into the depths of the internet unless you update Curb as well.\
WebMock will not complain about those requests not being stubbed.

One of the commits that made it into 1.8.0 actually breaks Curb versions below 0.7.16 while fixing it for that version (and above, hopefully).\
WebMock's hooks for Curl::Easy are sti...

Gatekeeping: Guide for developer

If your project manager wants to do gatekeeping on a project, as a developer you need to follow the following guidelines (e.g. by using something like this issue checklist template).

In order to reduce the number of rejects we get from clients, we want to review all code written before it goes to the staging server.

Note

This process is tailored to our specific needs and tools at makandra. While it will certainly not apply to all (especially larger teams), we think it...

Gatekeeping: Guide for gatekeeper

If you're responsible for gatekeeping in a projects, here is a guide, what to do.
In order to reduce the number of rejects we get from clients, we want to review all code written before it goes to the staging server.

Note: This process is tailored to our specific needs and tools at makandra. While it will certainly not apply to all (especially larger teams), we think it is a helpful starting point.


First, read the [Gatekeeping for developers](https://makandracards.com/makandra/6579-gatekeeping-guide-for...

ActiveRecord: When aggregating nested children, always exclude children marked for destruction

When your model is using a callback like before_save or before_validation to calculate an aggregated value from its children, it needs to skip those children that are #marked_for_destruction?. Otherwise you will include children that have been ticked for deletion in a nested form.

Wrong way

class Invoice < ApplicationRecord
  has_many :invoice_items
  accepts_nested_attributes_for :invoice_items, :allow_destroy => true # the critical code 1/2
  before_save :calculate_and_store_amount                              # the crit...

What collapsing margins are, how they work and when margins do not collapse

Imagine you have 2 HTML boxes. The first one has a margin-bottom of let's say 30px and the second one a margin-top of 20px. After rules of collapsing margins have been applied we have a margin of 30px (not 50px) between these two boxes . This is because no addition of both margins takes place but the maximum of both is applied. This behavior is called collapsing margins.

Oftentimes it is a good behavior but collapsing margins can be annoying, too. For example child el...

Nicer alternatives to def_delegator or def_delegators

Delegating methods to other objects is often helpful but the syntax of both def_delegators and def_delegator is a complete mess that makes your code hard to read.

Consider these classes:

class Topic < ActiveRecord::Base
  def title
    "A title"
  end
  
  def category
    "Topic category"
  end
end

class Post < ActiveRecord::Base
  belongs_to :topic
  def_delegato...

Run your own code before specific RSpec examples

You probably know about the possibility to tag scenarios in Cucumber to run your own piece of code before the actual scenario is run which looks like that:

@foo
Scenario: Do something
...

and you place the following snippet into support/env.rb:

Before('@foo') do
  puts "This is run every time a @foo tagged scenario is hit"
end    

You can tag RSpec examples like this:

it 'does something', :foo => true do
  ...
end

What you need is the following within the RSpec.configure do |config| block wit...

In MySQL, a zero number equals any string

In MySQL comparing zero to a string 0 = "any string" is always true!

So when you want to compare a string with a value of an integer column, you have to cast your integer value into a string like follows:

SELECT * from posts WHERE CAST(posts.comments_count AS CHAR) = '200' 

Of course this is usually not what you want to use for selecting your data as this might cause some expensive database operations. No indexes can be used and a full table scan will always be triggered.

If possible, cast the compared value in your application to...

RestClient sends XML Accept header by default

REST Client is a nice, simple HTTP client library for Ruby.

When you do a simple GET request like that:

RestClient.get 'http://example.com/'

it will result in this request beeing sent to www.example.com:

GET / HTTP/1.1
Accept: */*; q=0.5, application/xml
Accept-Encoding: gzip, deflate
Host: www.example.com

The application/xml accept header might lead to unexpected results on your server. You can force REST Client to ask the server for default text/html that way:

RestC...

How to overwrite and reset constants within Cucumber features

In order to save the original value of a constant, set the new value and restore the old value after a scenario was completed, you can use the following helper. It takes care of saving the old constant value, setting the new one without throwing warnings and resets the value with an After hook.

This module also enables you to introduce new global constants.
Since these newly defined constants do not have any value to be reset to,
they simply are deleted (remove_const) once the respective Cucumber step finishes.

You can copy the file at...

Cucumber step to test that a tooltip text exists in the HTML

Tooltips that are delivered through HTML attributes are encoded. Decode entities before checking for their presence.

Capybara:

Then /^there should( not)? be a(n encoded)? tooltip "([^"]*)"$/ do |negate, encoded, tooltip|
  tooltip = HTMLEntities.new.encode(tooltip) if encoded
  Then "I should#{negate} see \"#{tooltip}\" in the HTML"
end

Note

This step uses the htmlentities gem described in another card.

Ma...

Look up a gem's version history

Sometimes it might be helpful to have a version history for a gem, e.g. when you want to see if there is a newer Rails 2 version of your currently used gem.

At first you should search your gem at RubyGems. Example: will_paginate version history.

The "Tags" tab at GitHub might be helpful as well.

Fixing Graticule's "distance" for edge cases

Ever seen this error when using Graticule?

Numerical argument out of domain - acos

Similarly to the to_sql problem for some edge cases, Graticule::Distance::Spherical.distance (and possibly those of Graticule's other distance computation classes) is subject to Float rounding errors.

This can cause the above error, when the arc cosine of something slightly more than 1.0 is to be computed, e.g. for the (zero) distance b...

nruth/show_me_the_cookies - GitHub

Some helpers for poking around at your Capybara driven browser's cookies in integration tests.

Supports Capybara's bundled drivers (rack-test, Selenium Webdriver), and adapters for other drivers may be added.

Flexible overflow handling with CSS and JavaScript

You can use text-overflow to truncate a text using CSS but it does not fit fancy requirements.

Here is a hack for the special case where you want to truncate one of two strings in one line that can both vary in length, while fully keeping one of them. See this example screenshot where we never want to show an ellipsis for the distance:

![Flexible overflow with optional ellipsis](https://makandracards.com/makandra/5885-a-flexible-overflow-ellipsis/at...

Use CSS "text-overflow" to truncate long texts

When using Rails to truncate strings, you may end up with strings that are still too long for their container or are not as long as they could be. You can get a prettier result using stylesheets.

The CSS property text-overflow: ellipsis has been around for quite a long time now but since Firefox did not support it for ages, you did not use it. Since Firefox 7 you can!

Note that this only works for single-line texts. If you want to truncate tests across multiple lines, use a JavaScript solution like...

Mysql::Error: SAVEPOINT active_record_1 does not exist: ROLLBACK TO SAVEPOINT active_record_1 (ActiveRecord::StatementInvalid)

Possible Reason 1: parallel_tests - running more processes than features

If you run old versions of parallel_tests with more processes than you have Cucumber features, you will get errors like this in unexpected places:

This is a bug caused by multiple processes running the same features on the same database.

The bug is fixed in versions 0.6.18+.

Possib...