How to use let variables in rails console? - ruby

using
rspec 2.6.4
rails 3.1.6
How to use let variables in rails test console?
1.9.3-p0 :032 > let(:user) { create(:user) }
NoMethodError: undefined method `let' for main:Object
Please advise, which library should be required here?
For example: below is executed in console to use stub methods in console.
require 'rspec/mocks/standalone'
Is it possible, to define and call let variables in rails console?

If you are fine with let just creating globals, you can polyfill it like this:
def let(name)
Object.send :instance_variable_set, "##{name}", yield
Object.send :define_method, name do
Object.send :instance_variable_get, "##{name}"
end
end
Usage is the same as rspec:
irb(main):007:0> let(:foo) { 1 }
=> :foo
irb(main):008:0> foo
=> 1
though you really shouldn't be pasting your test code into console to debug it. It's much better to use a breakpoint tool like pry or byebug.

let in rspec is not much more than a lazily executed and memoized method definition. If you must have in the irb you could define it like this:
$ cat let.rb
def let(sym)
$let ||= {}
define_method sym do
$let[sym] ||= yield
end
end
require './let in irb or place it in .irbrc and you have your rspec-like let. Note, that rspec reevaluates let in each new example (it or specify block). Since you don't have them in irb you may need to clear your let cache manually ($let = {}) to force re-evaluation.

Related

Ruby Script: undefined method `symbolize_keys' error loading YAML files

I have a ruby script for yaml merging as follows
#!/usr/bin/env ruby
require 'yaml'
raise "wrong number of parameters" unless ARGV.length == 2
y1 = YAML.load_file(ARGV[0]).symbolize_keys
y2 = YAML.load_file(ARGV[1]).symbolize_keys
puts y1.merge!(y2).to_yaml
when I execute it:
./test.rb ./src/api/config/config1.yml ./src/api/config/config2.yml
I've got the following error:
./test.rb:5:in `<main>': undefined method `symbolize_keys' for {"root"=>{"cloud.n2"=>{"accessKey"=>"I5VAJUYNR4AAKIZDH777"}}}:Hash (NoMethodError)
Hash#symbolize_keys method comes from activesupport gem (activesupport/lib/active_support/core_ext/hash/keys.rb).
In order to use it, you need to add the following line to your script:
require "active_support"
While the other answers/comments are correct it seems like overkill to require all of ActiveSupport for this. Instead either use:
require 'active_support/core_ext/hash/keys'
Or if you have control over the yml files then just make the keys symbols there and avoid any transformation. For Example
require 'yaml'
yml = <<YML
:root:
:cloud.n2:
:accessKey: "I5VAJUYNR4AAKIZDH777"
YML
YAML.load(yml)
#=> {:root=>{:"cloud.n2"=>{:accessKey=>"I5VAJUYNR4AAKIZDH777"}}}
This does not really the answer your question, but Ruby 2.5.0 introduced Hash#transform_keys (release notes) which also can be used to symbolize keys and is in core Ruby.
{'a' => 1, 'b' => 2}.transform_keys(&:to_sym)
#=> {:a=>1, :b=>2}
There is also a bang version which mutates the hash instead of creating a new one.
As other have already noted, symbolize_keys is an ActiveSupport method. If you are not using ActiveSupport, and/or on a pre-2.5 version of Ruby that does not include transform_keys, you could define it yourself.
class Hash
def transform_keys
return enum_for(:transform_keys) unless block_given?
result = self.class.new
each_key do |key|
result[yield(key)] = self[key]
end
result
end
def transform_keys!
return enum_for(:transform_keys!) unless block_given?
keys.each do |key|
self[yield(key)] = delete(key)
end
self
end
def symbolize_keys
transform_keys{ |key| key.to_sym rescue key }
end
def symbolize_keys!
transform_keys!{ |key| key.to_sym rescue key }
end
end
This is not to say that there are not likely other dependencies on Rails or ActiveSupport that will be required for your script.

Can't access custom helper functions made within the file - Sinatra

I have this helper within my 'app.rb' file, which is used to get the current user object.
helpers do
def get_current_user(column, value)
user = User.where(column => value).first
return user
end
end
get '/' do
user = get_current_user(:id, params[:id])
end
This is what i did in irb:
irb(main):001:0> require './app'
=> true
irb(main):007:0> user = get_current_user(:id, 2)
NoMethodError: undefined method `get_current_user' for main:Object
from (irb):7
from /usr/bin/irb:12:in `<main>'
I don't understand why i can't access the helper methods from irb. Should i explicitly include the helpers or something? If so, why? Because i put them under the same file, under the same class.
get_current_users is metaprogrammed through the helpers method to be an instance method of App. So, if app.rb looks something like this:
require 'sinatra/base'
class App < Sinatra::Base
helpers do
def get_current_user
puts "here!"
end
end
end
...then from irb you can invoke get_current_user on an instance of App like this:
>> require './app'
>> App.new!.get_current_user
here!
=> nil
>>
(If you're wondering why that's new! and not new like most sane ruby code, read this answer.)

Why isn't this simple Ruby code working in HAML?

If I run this simple Ruby code regularly, it works fine:
class String
def add_two
self + "2"
end
end
puts "hello".add_two
It prints "hello2" as it should. But this fails:
:ruby
class String
def add_two
self + "2"
end
end
puts "hello".add_two
This code produces an error:
NoMethodError at /
undefined method `add_two' for "hello":String
Any ideas what's wrong?
(Not sure if it matters, but I'm using HAML with Sinatra, which is running on Apache with the Passenger module.)
I would suggest that String is in another namespace and therefor another class.
What happens with that?
class ::String
I put your code as is into one of my Haml views in a Rails app and I got a different error to you:
SyntaxError at /
class definition in method body
So I wondered whether it was Haml's :ruby filter that was complaining, but since it "Parses the filtered text with the normal Ruby interpreter", it seemed unlikely. So, I searched for more info about the error and found references (see below) that led me to this, which works (but, really, should never be used):
:ruby
String.module_eval do
def add_two
self + "2"
end
end
puts "hello".add_two
References:
Class inside a Method Body
Class (Re)definition in Method Body

Weird error when trying to test method with argument in Mocha. Is it a bug or is it me?

It's rather hard to find any documentation on Mocha, so I'm afraid I'm totally at sea here. I have found a problem with stubbing methods that pass arguments. So for instance if I set up a class like this:
class Red
def gets(*args)
#input.gets(*args)
end
def puts(*args)
#output.puts(*args)
end
def initialize
#input = $stdin
#output = $stdout
end
private
def first_method
input = gets.chomp
if input == "test"
second_method(input)
end
end
def second_method(value)
puts value
second_method(value)
end
end
Yes it's contrived, but it's a simplification of the idea that you may have a method that you don't want called in the test.
So I might write a test such as:
setup do
#project = Red.new
#project.instance_variable_set(:#input, StringIO.new("test\n"))
#project.stubs(:second_method)
end
should "pass input value to second_method" do
#project.expects(:second_method).with("test").once
#project.instance_eval {first_method}
end
Now I would expect this to pass. But instead I get this rather arcane error message:
Errno::ENOENT: No such file or directory - getcwd
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/backtrace_filter.rb:12:in `expand_path'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/backtrace_filter.rb:12:in `block in filtered'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/backtrace_filter.rb:12:in `reject'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/backtrace_filter.rb:12:in `filtered'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/expectation_error.rb:10:in `initialize'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/mockery.rb:53:in `new'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/mockery.rb:53:in `verify'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/api.rb:156:in `mocha_verify'
/Users/i0n/.rvm/gems/ruby-1.9.2-head/gems/mocha-0.9.8/lib/mocha/integration/mini_test/version_131_and_above.rb:27:in `run'
This means absolutely nothing to me, other than something deep in Mochas bowels has just gone clang. If I write the same sort of test without an argument passing to the second method I get no problem. Am I missing something?
I think it must be something in shoulda causing the problem. I use test/unit, and everything appears to be OK.
require 'rubygems'
require "test/unit"
require 'mocha'
require File.dirname(__FILE__) + '/../src/red'
class RedTest < Test::Unit::TestCase
def setup
#project = Red.new
#project.instance_variable_set(:#input, StringIO.new("test\n"))
#project.stubs(:second_method)
end
def test_description_of_thing_being_tested
#project.expects(:second_method).with("test").once
#project.instance_eval {first_method}
end
end
gives the following output:
stephen#iolanta:~/tmp/red/test # ruby red_test.rb
Loaded suite red_test
Started
.
Finished in 0.000679 seconds.
1 tests, 1 assertions, 0 failures, 0 errors
stephen#iolanta:~/tmp/red/test #
Sorry - I've only just seen this. It's better to submit bug reports to us in Lighthouse. What documentation have you found? Have you seen the RDoc on Rubyforge? What sort of documentation were you looking for that you did not find?
I've been unable to reproduce your bug. What version of Ruby, Rubygems, Shoulda & Mocha were you using?
You can see the results of me running your test in this Gist.

Printing the source code of a Ruby block

I have a method that takes a block.
Obviously I don't know what is going to be passed in and for bizarre reasons that I won't go into here I want to print the contents of the block.
Is there a way to do this?
You can do this with Ruby2Ruby which implements a to_ruby method.
require 'rubygems'
require 'parse_tree'
require 'parse_tree_extensions'
require 'ruby2ruby'
def meth &block
puts block.to_ruby
end
meth { some code }
will output:
"proc { some(code) }"
I would also check out this awesome talk by Chris Wanstrath of Github http://goruco2008.confreaks.com/03_wanstrath.html He shows some interesting ruby2ruby and parsetree usage examples.
In Ruby 1.9+ (tested with 2.1.2), you can use https://github.com/banister/method_source
Print out the source via block#source:
#! /usr/bin/ruby
require 'rubygems'
require 'method_source'
def wait &block
puts "Running the following code: #{block.source}"
puts "Result: #{yield}"
puts "Done"
end
def run!
x = 6
wait { x == 5 }
wait { x == 6 }
end
run!
Note that in order for the source to be read you need to use a file and execute the file (testing it out from irb will result in the following error: MethodSource::SourceNotFoundError: Could not load source for : No such file or directory # rb_sysopen - (irb)
Building on Evangenieur's answer, here's Corban's answer if you had Ruby 1.9:
# Works with Ruby 1.9
require 'sourcify'
def meth &block
# Note it's to_source, not to_ruby
puts block.to_source
end
meth { some code }
My company uses this to display the Ruby code used to make carbon calculations... we used ParseTree with Ruby 1.8 and now sourcify with Ruby 1.9.
In Ruby 1.9, you can try this gem which extract the code from source file.
https://github.com/ngty/sourcify
In Ruby 2.5 the following works
puts block.source
In ruby 2.7, using the method_source gem (pry depends on it)
Set.instance_method(:merge).source.display
# =>
def merge(enum)
if enum.instance_of?(self.class)
#hash.update(enum.instance_variable_get(:#hash))
else
do_with_enum(enum) { |o| add(o) }
end
self
end
The repo says it works for procs, but I haven't tested it.

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