I have a YAML file books.yaml:
- !ruby.object:Book
title: Ruby for Newbz
author: LeeRoy Jenkins
category: Educational
I already have a method that adds books to this file, but I need a method that can search the YAML file using a regular expression. If no book matches the title then it should raise an exception NoBookfound. If there are any matches, that list should be returned to the caller.
Here is my existing code:
require 'yaml'
require './book'
class Library
attr_accessor :books
def initialize file_name = false
#books = file_name ? YAML::load(File.read(file_name)) : []
end
def add_book(book)
#books.push(book)
end
def search_library(file_name , book)
if
YAML::load(File.read(file_name)).include?(book) == false
raise 'No Book Found'
end
end
end
This is something I tried for the exception portion, but I feel like I'm way off. I'm really new to Ruby and this seems to be a pretty hard task. Does anyone have any ideas?
What you need is to test the class from the loaded object:
book = YAML::load(File.read(file_name))
raise 'No Book Found' unless book.kind_of? Book
There are also some kind_of? alternatives, which you can read about the differences on this nice question
Based on your post, I guess that book param is a Regexp object.
I think you should remove the file_name param from search method, since the file is already loaded on initialize method.
My implemetation would be:
def search_library term
#books.find_all {|b| b.title =~ term}
end
Since you already have "#books" in an enumerable you can use the select method to find books whose title have the search term as a substring.
def search_library(term)
matches = #books.select { |x| x.title.index(term) }
raise "No books have title like '#{term}'" if matches.empty?
matches
end
Related
I am trying my hands at Ruby, below is the code that I am writing in 2 different ways to understand Ruby Classes. In first block I am using accessor method (combination of accessor read & write) and I want to print final line as "lord of the rings is written by Tolkien and has 400 pages". How can I make that happen? I understand that adding string and integer will throw an error. I can get them to print on separate lines, its just that I can't get them in a sentence.
class Book
attr_accessor :title, :author, :pages
end
book1 = Book.new()
book1.title = 'lord of the rings'
book1.author = 'Tolkien'
book1.pages = 400
puts book1.title
puts book1.author
puts book1.pages
#puts book1.title + " is written by " + book1.author + " and has " + book1.pages + " pages" <<<this errors out for known reason>>>
Second piece of code doing the same thing but I am using instance variable and have figured out how to get desired output. However, please advise if there's a better way of doing this?
class Novel
def initialize(title, author, pages)
#title = title
#author = author
#pages = pages
end
def inspect
"#{#title} is written by #{#author} and has #{#pages} pages"
end
end
novel1 = Novel.new('harry potter', 'JK Rowling', 300)
puts novel1.inspect
In your first example you are providing access the info you want and leaving it up to the client to format the output. For example you could have gotten what you wanted by adding this line in place of your commented line.
puts "#{book1.title} is written by #{book1.author} and has #{book1.pages} pages"
In your second example you are "pushing" that code down into the Novel class and proving a method to produce the output you want. BTW, don't use inspect as a method name, inspect is already a defined method
For example the following will print the same info twice.
class Novel
attr_accessor :title, :author, :pages
def initialize(title, author, pages)
#title = title
#author = author
#pages = pages
end
def info
"#{#title} is written by #{#author} and has #{#pages} pages"
end
end
novel = Novel.new('harry potter', 'JK Rowling', 300)
puts novel.info
puts "#{novel.title} is written by #{novel.author} and has #{novel.pages} pages"
Given the minimal example
# resources/novowel.rb
resource_name :novowel
property :name, String, name_property: true, regex: /\A[^aeiou]\z/
I would like to write the unit tests in spec/unit/resources/novowel_spec.rb
Resource 'novowel' for name should accept 'k'
Resource 'novowel' for name should accept '&'
Resource 'novowel' for name should NOT accept 'a'
Resource 'novowel' for name should NOT accept 'mm'
to ensure that the name property still works correctly even if the regex is changed for some reason.
I browsed several top notch Chef cookbooks but could not find references for such testing.
How can it be done? Feel free to provide more complex examples with explicitly subclassing Chef::Resource if that helps achieve the task.
Update 1: Could it be that Chef does NOT FAIL when a property does not fit the regex? Clearly this should not work:
link '/none' do
owner 'r<oo=t'
to '/usr'
end
but chef-apply (12.13.37) does not complain about r<oo=t not matching owner_valid_regex. It simply converges as if owner would not have been provided.
You would use ChefSpec and RSpec. I've got examples in all of my cookbooks (ex. https://github.com/poise/poise-python/tree/master/test/spec/resources) but I also use a bunch of custom helpers on top of plain ChefSpec so it might not be super helpful. Doing in-line recipe code blocks in the specs makes it waaaay easier. I've started extracting my helpers out for external use in https://github.com/poise/poise-spec but it's not finished. The current helpers are in my Halite gem, see the readme there for more info.
We wrap the DSL inside a little Ruby in order to know the name of the resource's Ruby class:
# libraries/no_vowel_resource.rb
require 'chef/resource'
class Chef
class Resource
class NoVowel < Chef::Resource
resource_name :novowel
property :letter, String, name_property: true, regex: /\A[^aeiou]\z/
property :author, String, regex: /\A[^aeiou]+\z/
end
end
end
and now we can use RSpec with
# spec/unit/libraries/no_vowel_resource_spec.rb
require 'spec_helper'
require_relative '../../../libraries/no_vowel_resource.rb'
describe Chef::Resource::NoVowel do
before(:each) do
#resource = described_class.new('k')
end
describe "property 'letter'" do
it "should accept the letter 'k'" do
#resource.letter = 'k'
expect(#resource.letter).to eq('k')
end
it "should accept the character '&'" do
#resource.letter = '&'
expect(#resource.letter).to eq('&')
end
it "should NOT accept the vowel 'a'" do
expect { #resource.letter = 'a' }.to raise_error(Chef::Exceptions::ValidationFailed)
end
it "should NOT accept the word 'mm'" do
expect { #resource.letter = 'mm' }.to raise_error(Chef::Exceptions::ValidationFailed)
end
end
describe "property 'author'" do
it "should accept a String without vowels" do
#resource.author = 'cdrngr'
expect(#resource.author).to eq('cdrngr')
end
it "should NOT accept a String with vowels" do
expect { #resource.author = 'coderanger' }.to raise_error(Chef::Exceptions::ValidationFailed)
end
end
end
I am using DataMapper for Database access. My goal is to send the models to an webservice as read-only object. This is my current try:
class User
include DataMapper::Resource
def to_yaml(opts = {})
mini_me = OpenStruct.new
instance_variables.each do |var|
next if /^#_/ =~ var.to_s
mini_me.send("#{var.to_s.gsub(/^#/, '')}=", instance_variable_get(var))
end
mini_me.to_yaml(opts)
end
....
end
YAML::ENGINE.yamler = 'psych'
u = User.get("hulk")
p u.to_yaml
# => "--- !ruby/object:OpenStruct\ntable:\n :uid: hulk\n :uidNumber: 1000\n :gidNumber: 1001\n :email: hulk#example.com\n :dn: uid=hulk,ou=People,o=example\n :name: Hulk\n :displayName: Hulk\n :description: Hulk\n :homeDirectory: /home/hulk\n :accountFlags: ! '[U ]'\n :sambaSID: S-1-5-21-......\nmodifiable: true\n"
p [ u ].to_yaml # TypeError: can't dump anonymous class Class
Any ideas how to make this work and get rid of the exception?
Thanks,
krissi
Using to_yaml is deprecated in Psych, and from my testing it seems to be actually broken in cases like this.
When you call to_yaml directly on your object, your method gets called and you get the result you expect. When you call it on the array containing your object, Psych serializes it but doesn’t correctly handle your to_yaml method, and ends up falling back onto the default serialization. In your case this results in an attempt to serialize an anonymous Class which causes the error.
To fix this, you should use the encode_with method instead. If it’s important that the serialized form is tagged as an OpenStruct object in the generated yaml you can use the represent_object (that first nil parameter doesn’t seem to be used):
def encode_with(coder)
mini_me = OpenStruct.new
instance_variables.each do |var|
next if /^#_/ =~ var.to_s
mini_me.send("#{var.to_s.gsub(/^#/, '')}=", instance_variable_get(var))
end
coder.represent_object(nil, mini_me)
end
If you were just using OpenStruct for convenience, an alternative could be something like:
def encode_with(coder)
instance_variables.each do |var|
next if /^#_/ =~ var.to_s
coder[var.to_s.gsub(/^#/, '')]= instance_variable_get(var)
end
end
Note that Datamapper has its own serializer plugin that provides yaml serialization for models, it might be worth looking into.
I have a line in my test:
page.has_reply?("my reply").must_equal true
and to make it more readable I want to use a custom matcher:
page.must_have_reply "my reply"
Based on the docs for https://github.com/zenspider/minitest-matchers I expect I need to write a matcher which looks something like this:
def have_reply(text)
subject.has_css?('.comment_body', :text => text)
end
MiniTest::Unit::TestCase.register_matcher :have_reply, :have_reply
The problem is that I can't see how to get a reference to the subject (i.e. the page object). The docs say "Note subject must be the first argument in assertion" but that doesn't really help.
There is a little example, you can create a class which should responds to set of methods matches?, failure_message_for_should, failure_message_for_should_not.
In matches? method you can get the reference to the subject.
class MyMatcher
def initialize(text)
#text = text
end
def matches? subject
subject =~ /^#{#text}.*/
end
def failure_message_for_should
"expected to start with #{#text}"
end
def failure_message_for_should_not
"expected not to start with #{#text}"
end
end
def start_with(text)
MyMatcher.new(text)
end
MiniTest::Unit::TestCase.register_matcher :start_with, :start_with
describe 'something' do
it 'must start with...' do
page = 'my reply'
page.must_start_with 'my reply'
page.must_start_with 'my '
end
end
There are many ways to get what you want here. The easiest way is to not mess with assertions, expectations, or matchers at all and just use an assert. So, assuming you already have the has_reply? method defined, you could just use this:
assert page.has_reply?("my reply")
But, that doesn't get you the must_have_reply syntax you are asking for. And I doubt you really have a has_reply? method. So, let's start.
Your asked "how to get a reference to the subject (i.e. the page object)". In this case the subject is the object that the must_have_reply method is defined on. So, you should use this instead of subject. But its not as straightforward as all that. Matchers add a level of indirection that we don't have with the usual Assertions (assert_equal, refute_equal) or Expectations (must_be_equal, wont_be_equal). If you want to write a Matcher you need to implement the Matcher API.
Fortunately for you you don't really have to implement the API. Since it seems you are already intending on relying on Cabybara's have_css matcher, we can simply use Capybara's HaveSelector class and let it implement the proper API. We just need to create our own Matchers module with a method that returns a HaveSelector object.
# Require Minitest Matchers to make this all work
require "minitest/matchers"
# Require Capybara's matchers so you can use them
require "capybara/rspec/matchers"
# Create your own matchers module
module YourApp
module Matchers
def have_reply text
# Return a properly configured HaveSelector instance
Capybara::RSpecMatchers::HaveSelector.new(:css, ".comment_body", :text => text)
end
# Register module using minitest-matcher syntax
def self.included base
instance_methods.each do |name|
base.register_matcher name, name
end
end
end
end
Then, in your minitest_helper.rb file, you can include your Matchers module so you can use it. (This code will include the matcher in all tests.)
class MiniTest::Rails::ActiveSupport::TestCase
# Include your module in the test case
include YourApp::Matchers
end
Minitest Matchers does all the hard lifting. You can now you can use your matcher as an assertion:
def test_using_an_assertion
visit root_path
assert_have_reply page, "my reply"
end
Or, you can use your matcher as an expectation:
it "is an expectation" do
visit root_path
page.must_have_reply "my reply"
end
And finally you can use it with a subject:
describe "with a subject" do
before { visit root_path }
subject { page }
it { must have_reply("my reply") }
must { have_reply "my reply" }
end
Important: For this to work, you must be using 'gem minitest-matchers', '>= 1.2.0' because register_matcher is not defined in earlier versions of that gem.
Let me preface by stating I'm a "new" programmer - an IT guy trying his hand at his first "real" problem after working through various tutorials.
So - here is what I'm trying to do. I'm watching a directory for a .csv file - it will be in this format: 999999_888_filename.csv
I want to return each part of the "_" filename as a variable to pass on to another program/script for some other task. I have come up w/ the following code:
require 'rubygems'
require 'fssm'
class Watcher
def start
monitor = FSSM::Monitor.new(:directories => true)
monitor.path('/data/testing/uploads') do |path|
path.update do |base, relative, ftype|
output(relative)
end
path.create do |base, relative, ftype|
output(relative)
end
path.delete { |base, relative, ftype| puts "DELETED #{relative} (#{ftype})" }
end
monitor.run
end
def output(relative)
puts "#{relative} added"
values = relative.split('_',)
sitenum = values[0]
numrecs = values[1]
filename = values[2]
puts sitenum
end
end
My first "puts" gives me the full filename (it's just there to show me the script is working), and the second puts returns the 'sitenum'. I want to be able to access this "outside" of this output method. I have this file (named watcher.rb) in a libs/ folder and I have a second file in the project root called 'monitor.rb' which contains simply:
require './lib/watcher'
watcher = Watcher.new
watcher.start
And I can't figure out how to access my 'sitenum', 'numrecs' and 'filename' from this file. I'm not sure if it needs to be a variable, instance variable or what. I've played around w/ attr_accessible and other things, and nothing works. I decided to ask here since I've been spinning my wheels for a couple of things, and I'm starting to confuse myself by searching on my own.
Thanks in advance for any help or advice you may have.
At the top of the Watcher class, you're going to want to define three attr_accessor declarations, which give the behavior you want. (attr_reader if you're only reading, attr_writer if you're only writing, attr_accessor if both.)
class Watcher
attr_accessor :sitenum, :numrecs, :filename
...
# later on, use # for class variables
...
#sitenum = 5
...
end
Now you should have no problem with watcher.sitenum etc. Here's an example.
EDIT: Some typos.
In addition to Jordan Scales' answer, these variable should initialized
class Watcher
attr_accessor :sitenum, :numrecs, :filename
def initialize
#sitenum = 'default value'
#numrecs = 'default value'
#filename = 'default value'
end
...
end
Otherwise you'll get uninformative value nil