Add RSpec warnings file, and fix small issues (#425)

* Add an RSpec configuration file and enable warnings.
* Drop unused variables in test
* Avoid "unary plus" warning
* Avoid "ambiguity" warning
* Fix test's quoting

Reinstate meaning of test: double quotes carry meaning here.

.rspec

@@ -0,0 +1,2 @@
+--require spec_helper
+--warnings

spec/sitemap_generator/adapters/google_storage_adapter_spec.rb

@@ -9,7 +9,6 @@
 
   shared_examples 'writes the raw data to a file and then uploads that file to Google Storage' do |acl|
     it 'writes the raw data to a file and then uploads that file to Google Storage' do
-      bucket = double(:bucket)
       storage = double(:storage)
       bucket_resource = double(:bucket_resource)
       expect(Google::Cloud::Storage).to receive(:new).with(credentials: 'abc', project_id: 'project_id').and_return(storage)

spec/sitemap_generator/builder/sitemap_url_spec.rb

@@ -90,8 +90,8 @@ def new_url(*args)
 
   it 'should not fail if invalid characters are used in the URL' do
     special = ':$&+,;:=?@'
-    url = SitemapGenerator::Builder::SitemapUrl.new('/#{special}', :host => 'http://example.com/#{special}/')
-    expect(url[:loc]).to eq('http://example.com/#{special}/#{special}')
+    url = SitemapGenerator::Builder::SitemapUrl.new("/#{special}", :host => "http://example.com/#{special}/")
+    expect(url[:loc]).to eq("http://example.com/#{special}/#{special}")
   end
 
   describe 'w3c_date' do

spec/sitemap_generator/core_ext/numeric_spec.rb

@@ -15,7 +15,7 @@ def numeric(size)
         numeric(1).kilobyte ** 4  => numeric(  1).terabyte,
         numeric(1024).kilobytes + numeric(2).megabytes =>   numeric(3).megabytes,
         numeric(             2).gigabytes / 4 => numeric(512).megabytes,
-        numeric(256).megabytes * 20 +numeric( 5).gigabytes => numeric(10).gigabytes,
+        numeric(256).megabytes * 20 + numeric( 5).gigabytes => numeric(10).gigabytes,
         numeric(1).kilobyte ** 5 => numeric(1).petabyte,
         numeric(1).kilobyte ** 6 => numeric(1).exabyte
       }

spec/sitemap_generator/sitemaps/mobile_sitemap_spec.rb

@@ -4,7 +4,6 @@
 
   it 'should add the mobile sitemap element' do
     loc = 'http://www.example.com/mobile_page.html'
-    format = 'html'
 
     mobile_xml_fragment = SitemapGenerator::Builder::SitemapUrl.new('mobile_page.html',
       :host => 'http://www.example.com',

spec/support/xml_macros.rb

@@ -54,10 +54,10 @@ def gzipped_xml_file_should_have_minimal_whitespace(xml_gz_filename)
   end
 
   def xml_data_should_have_minimal_whitespace(xml_data)
-    expect(xml_data).not_to match /^\s/
-    expect(xml_data).not_to match /\s$/
-    expect(xml_data).not_to match /\s\s+/
-    expect(xml_data).not_to match /\s[<>]/
-    expect(xml_data).not_to match /[<>]\s/
+    expect(xml_data).not_to match(/^\s/)
+    expect(xml_data).not_to match(/\s$/)
+    expect(xml_data).not_to match(/\s\s+/)
+    expect(xml_data).not_to match(/\s[<>]/)
+    expect(xml_data).not_to match(/[<>]\s/)
   end
 end