ActiveMocker
ActiveMocker creates mocks classes from ActiveRecord models. Allowing your test suite to run very fast by not loading Rails or hooking to a database. It parses the schema.rb and the defined methods on a model then generates a ruby file that can be included within a test. The mock file can be run by themselves and come with a partial implementation of ActiveRecord. Attributes and associations can be used just the same as in ActiveRecord. Methods will have the correct arguments but raise an NotImplementedError when called. Mocks are regenerated when the schema is modified so your mocks will not go stale; preventing the case where your units tests pass but production code fails.
Examples from a real apps
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- Documentation
- Contact
- Installation
- Setup
- Dependencies
- Usage
- Mocking Methods
- Managing Mocks
- ActiveRecord supported methods
- Known Limitations
- Inspiration
- Contributing
Documentation
Contact
Ask a question in the chat room.
Installation
Add this line to your application's Gemfile:
group :development, :test do
gem 'active_mocker'
end
It needs to be in development as well as test because development is where mocks will be generated. And then execute:
$ bundle
Or install it yourself as:
$ gem install active_mocker
Dependencies
- Tested with Rails 4.1 may work with older versions but not supported.
- Requires Ruby MRI >= 2.1.
Setup
See example_rails_app for complete setup.
Generate Mocks
Running this rake task builds/rebuilds the mocks. It will be ran automatically after every schema modification. If the model changes this rake task needs to be called manually. You could add a file watcher for when your models change and have it run the rake task.
rake active_mocker:build
Usage
#db/schema.rb
ActiveRecord::Schema.define(version: 20140327205359) do
create_table "people", force: true do |t|
t.integer "account_id"
t.string "first_name", limit: 128
t.string "last_name", limit: 128
t.string "address", limit: 200
t.string "city", limit: 100
end
end
#app/models/person.rb
class Person < ActiveRecord::Base
belongs_to :account
def (name, type=nil)
puts name
end
def self.
end
end
Using With Rspec, --tag active_mocker:true
require 'rspec'
require 'active_mocker/rspec_helper'
require 'spec/mocks/person_mock'
require 'spec/mocks/account_mock'
describe 'Example', active_mocker:true do
before do
Person.create # stubbed for PersonMock.create
end
end
- Assigning the tag
active_mocker:true
will stub any ActiveRecord model Constants for Mock classes in anit
or abefore/after(:each)
. This removes any need for dependency injection. Write tests and code like you would normally. - To stub any Constants in
before(:all)
,after(:all)
usemock_class('ClassName')
. - Mock state will be cleaned up for you in an
after(:all)
. To clean state your self useActiveMocker::LoadedMocks.delete_all
.
Person.column_names
=> ["id", "account_id", "first_name", "last_name", "address", "city"]
person = Person.new( first_name: "Dustin",
last_name: "Zeisler",
account: Account.new )
=> "#<PersonMock id: nil, account_id: nil, first_name: "Dustin", last_name: "Zeisler", address: nil, city: nil>"
person.first_name
=> "Dustin"
When schema.rb changes, the mock fails
(After rake db:migrate
is called the mocks will be regenerated.)
#db/schema.rb
ActiveRecord::Schema.define(version: 20140327205359) do
create_table "people", force: true do |t|
t.integer "account_id"
t.string "f_name", limit: 128
t.string "l_name", limit: 128
t.string "address", limit: 200
t.string "city", limit: 100
end
end
Person.new(first_name: "Dustin", last_name: "Zeisler")
=>#<UnknownAttributeError unknown attribute: first_name >
Mocking Methods
Rspec 3 Mocks - verify double
Verifying doubles are a stricter alternative to normal doubles that provide guarantees about what is being verified. When using verifying doubles, RSpec will check that the methods being stubbed are actually present on the underlying object if it is available. rspec-mocks/docs/verifying-doubles
RSpec.configure do |config|
config.mock_framework = :rspec
config.mock_with :rspec do |mocks|
mocks.verify_doubled_constant_names = true
mocks.verify_partial_doubles = true
end
end
Person.bar('baz')
=> NotImplementedError: ::bar is not Implemented for Class :PersonMock. To continue stub the method.
allow(Person).to receive(:bar) do |name, type=nil|
"Now implemented with #{name} and #{type}"
end
Person.bar('foo', 'type')
=> "Now implemented with foo and type"
# Rspec 3 mock class method
allow_any_instance_of(Person).to receive(:bar) do
"Now implemented"
end
When the model changes, the mock fails
(Requires a regeneration of the mocks files.)
#app/models/person.rb
class Person < ActiveRecord::Base
belongs_to :account
def (name)
puts name
end
end
Person.new.bar('foo', 'type')
=> ArgumentError: wrong number of arguments (2 for 1)
#app/models/person.rb
class Person < ActiveRecord::Base
belongs_to :account
def foo(name, type=nil)
puts name
end
end
allow(person).to receive(:bar) do |name, type=nil|
"Now implemented with #{name} and #{type}"
end
=> NoMethodError : undefined method `bar' for class ` PersonMock '
Constants and Modules
- Any locally defined modules will not be included or extended.
class Person < ActiveRecord::Base
CONSTANT_VALUE = 13
end
PersonMock::CONSTANT_VALUE
=> 13
Scoped Methods
- Any chained scoped methods will be available when the mock file that defines it is required. When called it raises a
NotImplementedError
, stub the method with a value to continue.
Managing Mocks
Deletes All Records for Loaded Mocks - (Useful in after(:each) to clean up state between examples)
ActiveMocker::LoadedMocks.delete_all
ActiveRecord supported methods
See Documentation for a complete list of methods and usage.
Class Methods - docs
- new
- create/create!
- column_names/attribute_names
- delete_all/destroy_all
- table_name
Query Methods - docs
- all
- find
- find_by/find_by!
- find_or_create_by
- find_or_initialize_by
- where(conditions_hash)
- where(key: array_of_values)
- where.not(conditions_hash)
- delete_all/destroy_all
- delete_all(conditions_hash)
- destroy(id)/delete(id)
- update_all
- update(id, attributes)
- count
- uniq
- first/last
- average(:field_name)
- minimum(:field_name)
- maximum(:field_name)
- sum(:field_name)
- order(:field_name)
- reverse_order
- limit
Relation Methods - docs
- concat
- include
- push
- clear
- take
- empty?
- replace
- any?
- many?
instance methods - docs
- attributes
- update
- save/save!
- write_attribute/read_attribute - (protected, can be used within modules)
- delete
- new_record?
- persisted?
- reload
- attribute_names
- attribute_present?
- has_attribute?
has_one/belongs_to/has_many
- build_< association >
- create_< association >
- create_< association >!
- < association >.create
- < association >.build
Schema/Migration Option Support
- All schema types are supported and coerced by Virtus. If coercion fails the passed value will be retained.
- Default value is supported.
- Scale and Precision are not supported.
Known Limitations
- Model names and table names must follow the default ActiveRecord naming pattern.
- When an association is set in one object it may not always be reflective in other objects, especially when it is a non standard/custom association. See test_rails_4_app/spec/active_record_compatible_api.rb for a complete list of supported associations.
- Validation/Callbacks are not supported.
- Sql queries, joins, etc will never be supported.
Inspiration
Thanks to Jeff Olfert for being my original inspiration for this project.
Contributing
Your contribution are welcome!
- Fork it ( http://github.com/zeisler/active_mocker/fork )
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create new Pull Request