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module Shoulda
module Matchers
module ActiveRecord
# The `have_db_index` matcher tests that the table that backs your model
# has a index on a specific column.
#
# class CreateBlogs < ActiveRecord::Migration
# def change
# create_table :blogs do |t|
# t.integer :user_id
# end
#
# add_index :blogs, :user_id
# end
# end
#
# # RSpec
# RSpec.describe Blog, type: :model do
# it { should have_db_index(:user_id) }
# end
#
# # Minitest (Shoulda)
# class BlogTest < ActiveSupport::TestCase
# should have_db_index(:user_id)
# end
#
# #### Qualifiers
#
# ##### unique
#
# Use `unique` to assert that the index is unique.
#
# class CreateBlogs < ActiveRecord::Migration
# def change
# create_table :blogs do |t|
# t.string :name
# end
#
# add_index :blogs, :name, unique: true
# end
# end
#
# # RSpec
# RSpec.describe Blog, type: :model do
# it { should have_db_index(:name).unique(true) }
# end
#
# # Minitest (Shoulda)
# class BlogTest < ActiveSupport::TestCase
# should have_db_index(:name).unique(true)
# end
#
# Since it only ever makes since for `unique` to be `true`, you can also
# leave off the argument to save some keystrokes:
#
# # RSpec
# RSpec.describe Blog, type: :model do
# it { should have_db_index(:name).unique }
# end
#
# # Minitest (Shoulda)
# class BlogTest < ActiveSupport::TestCase
# should have_db_index(:name).unique
# end
#
# @return [HaveDbIndexMatcher]
#
def have_db_index(columns)
HaveDbIndexMatcher.new(columns)
end
# @private
class HaveDbIndexMatcher
def initialize(columns)
@columns = normalize_columns_to_array(columns)
@options = {}
end
def unique(unique = true)
@options[:unique] = unique
self
end
def matches?(subject)
@subject = subject
index_exists? && correct_unique?
end
def failure_message
"Expected #{expectation} (#{@missing})"
end
def failure_message_when_negated
"Did not expect #{expectation}"
end
def description
if @options.key?(:unique)
"have a #{index_type} index on columns #{@columns.join(' and ')}"
else
"have an index on columns #{@columns.join(' and ')}"
end
end
protected
def index_exists?
! matched_index.nil?
end
def correct_unique?
return true unless @options.key?(:unique)
is_unique = matched_index.unique
is_unique = !is_unique unless @options[:unique]
unless is_unique
@missing = "#{table_name} has an index named #{matched_index.name} " <<
"of unique #{matched_index.unique}, not #{@options[:unique]}."
end
is_unique
end
def matched_index
indexes.detect { |each| each.columns == @columns }
end
def model_class
@subject.class
end
def table_name
model_class.table_name
end
def indexes
::ActiveRecord::Base.connection.indexes(table_name)
end
def expectation
"#{model_class.name} to #{description}"
end
def index_type
if @options[:unique]
'unique'
else
'non-unique'
end
end
def normalize_columns_to_array(columns)
Array.wrap(columns).map(&:to_s)
end
end
end
end
end