add retry monkey patch for mechanize

config/initializers/mechanize_patch.rb

@@ -0,0 +1,57 @@
+require 'mechanize'
+
+if Rails.env.test?
+  class Mechanize::HTTP::Agent
+    MAX_RESET_RETRIES = 10
+
+    # We need to replace the core Mechanize HTTP method:
+    #
+    #   Mechanize::HTTP::Agent#fetch
+    #
+    # with a wrapper that handles the infamous "too many connection resets"
+    # Mechanize bug that is described here:
+    #
+    #   https://github.com/sparklemotion/mechanize/issues/123
+    #
+    # The wrapper shuts down the persistent HTTP connection when it fails with
+    # this error, and simply tries again. In practice, this only ever needs to
+    # be retried once, but I am going to let it retry a few times
+    # (MAX_RESET_RETRIES), just in case.
+    #
+    def fetch_with_retry(
+      uri,
+      method    = :get,
+      headers   = {},
+      params    = [],
+      referer   = current_page,
+      redirects = 0
+    )
+      action      = "#{method.to_s.upcase} #{uri.to_s}"
+      retry_count = 0
+
+      begin
+        fetch_without_retry(uri, method, headers, params, referer, redirects)
+      rescue Net::HTTP::Persistent::Error => e
+        # Pass on any other type of error.
+        raise unless e.message =~ /too many connection resets/
+
+        # Pass on the error if we've tried too many times.
+        if retry_count >= MAX_RESET_RETRIES
+          puts "**** WARN: Mechanize retried connection reset #{MAX_RESET_RETRIES} times and never succeeded: #{action}"
+          raise
+        end
+
+        # Otherwise, shutdown the persistent HTTP connection and try again.
+        puts "**** WARN: Mechanize retrying connection reset error: #{action}"
+        retry_count += 1
+        self.http.shutdown
+        retry
+      end
+    end
+
+    # Alias so #fetch actually uses our new #fetch_with_retry to wrap the
+    # old one aliased as #fetch_without_retry.
+    alias_method :fetch_without_retry, :fetch
+    alias_method :fetch, :fetch_with_retry
+  end
+end

test/unit/downloads/pixiv_test.rb

@@ -2,13 +2,6 @@ require 'test_helper'
 
 module Downloads
   class PixivTest < ActiveSupport::TestCase
-    def teardown
-      super
-
-      # need to reset the connection
-      Sources::Strategies::Pixiv.new("http://www.pixiv.net").agent.shutdown
-    end
-
     context "An ugoira site for pixiv" do
       setup do
         @download = Downloads::File.new("http://www.pixiv.net/member_illust.php?mode=medium&illust_id=62247364")

test/unit/sources/pixiv_test.rb

@@ -8,13 +8,6 @@ module Sources
       @site
     end
 
-    def teardown
-      super
-
-      # need to reset the connection
-      Sources::Strategies::Pixiv.new("http://www.pixiv.net").agent.shutdown
-    end
-
     context "in all cases" do
       context "A touch page" do
         setup do