added regexp for validating postgres arrays and specs for the regexp

.gitignore

@@ -1,3 +1,4 @@
 .DS_Store
 *.gem
 .bundle
+Gemfile.lock

.rspec

@@ -0,0 +1,2 @@
+--color
+--format progress

Gemfile

@@ -0,0 +1,3 @@
+source :rubygems
+
+gemspec

Rakefile

@@ -0,0 +1,13 @@
+#!/usr/bin/env rake
+begin
+  require 'bundler/setup'
+rescue LoadError
+  puts 'You must `gem install bundler` and `bundle install` to run rake tasks'
+end
+
+Bundler::GemHelper.install_tasks
+
+require 'rspec/core/rake_task'
+RSpec::Core::RakeTask.new
+
+task :default => :spec

activerecord-postgres-array.gemspec

@@ -16,5 +16,8 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
   s.rubygems_version = %q{1.3.7}
   s.summary = s.description
+
+  s.add_development_dependency 'rake'
+  s.add_development_dependency 'rspec', '~> 2.0'
 end
 

lib/activerecord-postgres-array/string.rb

@@ -1,5 +1,4 @@
 class String
-
   def to_postgres_array
     self
   end
@@ -9,8 +8,9 @@ def to_postgres_array
   # * A string like '{10000, 10000, 10000, 10000}'
   # * TODO A multi dimensional array string like '{{"meeting", "lunch"}, {"training", "presentation"}}'
   def valid_postgres_array?
-    # TODO validate formats above
-    true
+    quoted_string_regexp = /"[^"\\]*(?:\\.[^"\\]*)*"|'[^'\\]*(?:\\.[^'\\]*)*'/
+    number_regexp = /[-+]?[0-9]*\.?[0-9]+/
+    !!match(/^\s*(\{\s*(#{number_regexp}|#{quoted_string_regexp})(\s*\,\s*(#{number_regexp}|#{quoted_string_regexp}))*\})?\s*$/)
   end
 
   # Creates an array from a postgres array string that postgresql spits out.

spec/spec_helper.rb

@@ -0,0 +1,5 @@
+RSpec.configure do |config|
+  config.treat_symbols_as_metadata_keys_with_true_values = true
+  config.run_all_when_everything_filtered = true
+  config.filter_run :focus
+end

spec/string_ext_spec.rb

@@ -0,0 +1,50 @@
+require 'spec_helper'
+require 'activerecord-postgres-array/string'
+
+describe "String" do
+  describe "#valid_postgres_array?" do
+    it 'returns true for an empty string' do
+      "".should be_valid_postgres_array
+    end
+
+    it 'returns true for a string consisting only of whitespace' do
+      "   ".should be_valid_postgres_array
+    end
+
+    it 'returns true for a valid postgres integer array' do
+      "{10000, 10000, 10000, 10000}".should be_valid_postgres_array
+    end
+
+    it 'returns true for a valid postgres float array' do
+      "{10000.2, .5, 10000, 10000.9}".should be_valid_postgres_array
+    end
+
+    it 'returns true for a valid postgres numerical array with irregular whitespace' do
+      "{   10000,   10000  ,  10000,10000}".should be_valid_postgres_array
+    end
+
+    it 'returns false for an array with invalid commas' do
+      "{213,}".should_not be_valid_postgres_array
+    end
+
+    it 'returns false for an array without enclosing curly brackets' do
+      "213, 1234".should_not be_valid_postgres_array
+    end
+
+    it 'returns true for a valid postgres string array' do
+      '{"ruby", "on", "rails"}'.should be_valid_postgres_array
+    end
+
+    it 'returns true for a valid postgres string array with single quotes' do
+      "{'ruby', 'on', 'rails'}".should be_valid_postgres_array
+    end
+
+    it 'returns false for string array without quotes' do
+      "{ruby, on, rails}".should_not be_valid_postgres_array
+    end
+
+    it 'returns false for concatenated strings' do
+      '{"ruby""on""rails"}'.should_not be_valid_postgres_array
+    end
+  end
+end