Adds specs and finalizes library code to ensure that .env.example declared variables are set

Author: Ricardo Quiñones

Diff for: .ruby-version

@@ -0,0 +1 @@
+2.2.2

Diff for: dotenv_safe.gemspec

@@ -16,6 +16,7 @@ Gem::Specification.new do |spec|
   }
   spec.homepage      = "https://github/wework/dotenv_safe"
   spec.license       = "MIT"
+  spec.required_ruby_version = '>= 2.2.2'
 
   # Prevent pushing this gem to RubyGems.org. To allow pushes either set the 'allowed_push_host'
   # to allow pushing to a single host or delete this section to allow pushing to any host.
@@ -33,8 +34,11 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
+  spec.add_dependency "dotenv-rails", '~> 2.1.1'
+
   spec.add_development_dependency "bundler", "~> 1.13"
   spec.add_development_dependency "rake", "~> 10.0"
   spec.add_development_dependency "rspec", "~> 3.0"
+  spec.add_development_dependency "rails", "~> 4.0"
   spec.add_development_dependency "pry"
 end

Diff for: lib/dotenv_safe.rb

@@ -1,4 +1,4 @@
-require "dotenv_safe/version"
+require 'dotenv_safe/version'
 require 'dotenv_safe/railtie' if defined?(Rails)
 
 module DotenvSafe

Diff for: lib/dotenv_safe/railtie.rb

@@ -1,11 +1,62 @@
+require 'dotenv'
+
 module DotenvSafe
-  class Railtie < Rails::Railtie
+  class MissingEnvVarError < StandardError; end
+
+  class Railtie < ::Rails::Railtie
     config.before_configuration do
+      # Make sure to force load environment variables for dotenv in development
+      if Rails.env.development?
+        Dotenv::Railtie.load
+      end
+
       check_env_vars
     end
 
     def check_env_vars
-      raise StandardError.new('I am an error')
+      missing_env_vars = aggregate_missing_env_vars
+
+      if missing_env_vars.any?
+        raise MissingEnvVarError.new([
+          'Missing the following environment variables: ',
+          missing_env_vars.to_sentence
+        ].join(''))
+      end
+    end
+
+    private
+
+    # Returns an array of missing environment variables
+    #
+    # @return [Array<String>]
+    def aggregate_missing_env_vars
+      example_env_vars.inject([]) do |array, key_and_value|
+        key = key_and_value[0]
+
+        begin
+          ENV.fetch(key)
+          array
+        rescue KeyError
+          array << key
+        end
+      end
+    end
+
+    # Returns a hash of environment variables defined in `.env.example`
+    #
+    # @return [Hash]
+    def example_env_vars
+      Dotenv::Parser.call(read)
+    rescue Errno::ENOENT, Dotenv::FormatError
+      {}
+    end
+
+    def read
+      File.open(root.join('.env.example'), "rb:bom|utf-8", &:read)
+    end
+
+    def root
+      Rails.root || Pathname.new(ENV["RAILS_ROOT"] || Dir.pwd)
     end
   end
 end

Diff for: spec/dotenv_safe_spec.rb

@@ -1,11 +1,116 @@
 require "spec_helper"
 
 describe DotenvSafe do
-  it "has a version number" do
-    expect(DotenvSafe::VERSION).not_to be nil
+  let(:rail_tie) { DotenvSafe::Railtie.send(:new) }
+
+  describe '#check_env_vars' do
+    let(:valid_env_file_contents) do
+      [
+        "FOO=bar\n",
+        "BAR=\n",
+      ].join('')
+    end
+
+    let(:invalid_env_file_contents) do
+      [
+        "FOO=\n",
+        "BAR=foo\n",
+        "NOT_SET_1=foo\n",
+        "NOT_SET_2=\n",
+      ].join('')
+    end
+
+    before do
+      allow(ENV).to receive(:fetch)
+      allow(ENV).to receive(:fetch).with('FOO').and_return('bar')
+      allow(ENV).to receive(:fetch).with('BAR').and_return('foo')
+      allow(ENV).to receive(:fetch).with('NOT_SET_1').and_raise(KeyError)
+      allow(ENV).to receive(:fetch).with('NOT_SET_2').and_raise(KeyError)
+    end
+
+    context 'with all required environment variables set' do
+      it 'should not raise an error when all the variables are present' do
+        allow(rail_tie).to receive(:read).and_return(valid_env_file_contents)
+        expect { rail_tie.check_env_vars }.to_not raise_error
+      end
+    end
+
+    context 'with some required environment variables not set' do
+      it 'should raise an error when missing required environment variables' do
+        allow(rail_tie).to receive(:read).and_return(invalid_env_file_contents)
+        expect {
+          rail_tie.check_env_vars
+        }.to raise_error(DotenvSafe::MissingEnvVarError)
+      end
+    end
   end
 
-  it "does something useful" do
-    expect(false).to eq(true)
+  describe '#example_env_vars' do
+    context 'with no .env.example file' do
+      it 'returns an empty array if no file found' do
+        expect(rail_tie.send(:example_env_vars)).to eq({})
+      end
+    end
+
+    context 'with .env.example file' do
+      context 'with no valid environment variables' do
+        let(:invalid_env_file_contents) do
+          [
+            "foo\n",
+            "bar\n",
+            "stuff\n",
+          ].join('')
+        end
+
+        before do
+          allow(rail_tie).to receive(:read).and_return(invalid_env_file_contents)
+        end
+
+        it 'returns an empty hash' do
+          expect(rail_tie.send(:example_env_vars)).to eq({})
+        end
+      end
+
+      context 'with valid environment variables' do
+        context 'without comments' do
+          let(:valid_env_file_contents) do
+            [
+              "FOO_VAR=bar\n",
+              "BAR_VAR=foo\n",
+            ].join('')
+          end
+
+          before do
+            allow(rail_tie).to receive(:read).and_return(valid_env_file_contents)
+          end
+
+          it 'returns some example env vars' do
+            expect(rail_tie.send(:example_env_vars)).to eq({
+              'FOO_VAR' => 'bar',
+              'BAR_VAR' => 'foo',
+            })
+          end
+        end
+
+        context 'with comments' do
+          let(:valid_env_file_contents) do
+            [
+              "FOO_VAR=bar\n",
+              "# BAR_VAR=foo\n",
+            ].join('')
+          end
+
+          before do
+            allow(rail_tie).to receive(:read).and_return(valid_env_file_contents)
+          end
+
+          it 'returns non-commented out example env vars' do
+            expect(rail_tie.send(:example_env_vars)).to eq({
+              'FOO_VAR' => 'bar',
+            })
+          end
+        end
+      end
+    end
   end
 end

Diff for: spec/spec_helper.rb

@@ -1,2 +1,5 @@
 $LOAD_PATH.unshift File.expand_path("../../lib", __FILE__)
-require "dotenv_safe"
+require 'pry'
+require 'dotenv_safe'
+require 'rails'
+require 'dotenv_safe/railtie' # explicit require for testing