Replace EmbiggenedURI#reason with #error

Rather than preserving only a string message describing the cause of an
expansion failure, expose the actual error object (which can then be
interrogated for its message).

README.md

@@ -50,10 +50,12 @@ uri.success?
 # If there weren't successful, you can ask them why
 uri.success?
 #=> false
-uri.reason
-#=> 'following https://youtu.be/dQw4w9WgXcQ did not redirect'
+uri.error
+#=> #<Embiggen::TooManyRedirects ...>
 # or
-#=> 'https://youtu.be/dQw4w9WgXcQ redirected too many times'
+#=> #<Embiggen::BadShortenedURI ...>
+# or
+#=> #<Timeout::Error ...>
 
 # Before expansion, you can check whether a URI is shortened or not
 Embiggen::URI('https://youtu.be/dQw4w9WgXcQ').shortened?

lib/embiggen/bad_shortened_uri.rb

@@ -0,0 +1,9 @@
+require 'embiggen/error'
+
+module Embiggen
+  class BadShortenedURI < Error
+    def self.for(uri)
+      new("following #{uri} did not redirect")
+    end
+  end
+end

lib/embiggen/embiggened_uri.rb

@@ -3,7 +3,7 @@
 module Embiggen
   class EmbiggenedURI
     extend Forwardable
-    attr_reader :uri, :success, :reason
+    attr_reader :uri, :success, :error
     alias_method :success?, :success
     def_delegators :uri, :to_s, :fragment, :host, :path, :port, :query,
                    :scheme, :request_uri
@@ -12,14 +12,14 @@ def self.success(uri)
       new(uri, :success => true)
     end
 
-    def self.failure(uri, reason = nil)
-      new(uri, :success => false, :reason => reason)
+    def self.failure(uri, error = nil)
+      new(uri, :success => false, :error => error)
     end
 
     def initialize(uri, options = {})
       @uri = uri
-      @success = options.fetch(:success)
-      @reason = options[:reason]
+      @success = options.fetch(:success) { !options.key?(:error) }
+      @error = options[:error]
     end
 
     def inspect

lib/embiggen/error.rb

@@ -0,0 +1,4 @@
+module Embiggen
+  class Error < ::RuntimeError
+  end
+end

lib/embiggen/too_many_redirects.rb

@@ -0,0 +1,9 @@
+require 'embiggen/error'
+
+module Embiggen
+  class TooManyRedirects < Error
+    def self.for(uri)
+      new("#{uri} redirected too many times")
+    end
+  end
+end

lib/embiggen/uri.rb

@@ -1,5 +1,7 @@
 require 'embiggen/embiggened_uri'
 require 'embiggen/configuration'
+require 'embiggen/too_many_redirects'
+require 'embiggen/bad_shortened_uri'
 require 'net/http'
 
 module Embiggen
@@ -15,7 +17,7 @@ def expand(request_options = {})
 
       follow_redirects(request_options)
     rescue ::Timeout::Error, ::Errno::ECONNRESET => e
-      EmbiggenedURI.failure(uri, e.message)
+      EmbiggenedURI.failure(uri, e)
     end
 
     def expand!(request_options = {})
@@ -41,23 +43,20 @@ def inspect
 
     def follow_redirects(request_options = {})
       redirects = request_options.fetch(:redirects) { Configuration.redirects }
-      return EmbiggenedURI.failure(uri) if redirects.zero?
+      return too_many_redirects if redirects.zero?
 
       location = head_location(request_options)
-      return EmbiggenedURI.failure(uri, "following #{uri} did not " \
-                                        'redirect') unless location
+      return bad_shortened_uri unless location
 
       location.expand(request_options.merge(:redirects => redirects - 1))
     end
 
     def follow_redirects!(request_options = {})
       redirects = request_options.fetch(:redirects) { Configuration.redirects }
-      fail TooManyRedirects, "#{uri} redirected too many " \
-                             'times' if redirects.zero?
+      fail TooManyRedirects.for(uri) if redirects.zero?
 
       location = head_location(request_options)
-      fail BadShortenedURI, "following #{uri} did not " \
-                            'redirect' unless location
+      fail BadShortenedURI.for(uri) unless location
 
       location.expand!(request_options.merge(:redirects => redirects - 1))
     end
@@ -80,9 +79,13 @@ def http
 
       http
     end
-  end
 
-  class Error < ::StandardError; end
-  class BadShortenedURI < Error; end
-  class TooManyRedirects < Error; end
+    def too_many_redirects
+      EmbiggenedURI.failure(uri, TooManyRedirects.for(uri))
+    end
+
+    def bad_shortened_uri
+      EmbiggenedURI.failure(uri, BadShortenedURI.for(uri))
+    end
+  end
 end

spec/embiggen/embiggened_uri_spec.rb

@@ -17,14 +17,21 @@ module Embiggen
         expect(failed_uri).to_not be_success
       end
 
-      it 'takes an optional reason for failure' do
+      it 'takes an optional cause for failure' do
         uri = URI.new('http://bit.ly/bad')
-        failed_uri = described_class.failure(uri, 'something went wrong')
+        error = Error.new('whoops')
+        failed_uri = described_class.failure(uri, error)
 
-        expect(failed_uri.reason).to eq('something went wrong')
+        expect(failed_uri.error).to eq(error)
       end
     end
 
+    it 'defaults to being successful if there is no error' do
+      uri = described_class.new(URI('http://www.altmetric.com'))
+
+      expect(uri).to be_success
+    end
+
     describe '#uri' do
       it 'returns the URI within' do
         uri = described_class.success(URI('http://www.altmetric.com'))