Introduce AccountMessageImporter.

As mentioned in 623566, we don't think that the MessageImporter should
be responsible for instantiating an IMAP connection and importing
messages into the repository.

lib/account_message_importer.rb

@@ -0,0 +1,11 @@
+require 'gmail_imap_client'
+require 'message_repository'
+
+class AccountMessageImporter
+  class << self
+    def import_for(email, password)
+      imap_client = GmailImapClient.connect(email, password)
+      MessageImporter.new(imap_client).import_into(MessageRepository.instance)
+    end
+  end
+end

lib/message_importer.rb

@@ -1,15 +1,4 @@
-require 'gmail_imap_client'
-require 'message_repository'
-
 class MessageImporter
-
-  class << self
-    def import_for(email, password)
-      imap_client = GmailImapClient.connect(email, password)
-      new(imap_client).import_into(MessageRepository.instance)
-    end
-  end
-
   attr_reader :message_client
 
   def initialize(message_client)

test/unit/account_message_importer_test.rb

@@ -0,0 +1,31 @@
+require 'test_helper'
+require 'account_message_importer'
+
+class AccountMessageImporterTest < ActiveSupport::TestCase
+  test 'establishes an imap connection using the given credentials' do
+    GmailImapClient.expects(:connect).with('dave@example.com', 'password')
+    MessageImporter.stubs(:new).returns(stub_everything)
+
+    AccountMessageImporter.import_for('dave@example.com', 'password')
+  end
+
+  test 'uses the established connection for importing' do
+    gmail_client = stub('gmail-client')
+    GmailImapClient.stubs(:connect).returns(gmail_client)
+    MessageImporter.expects(:new).with(gmail_client).returns(stub_everything)
+
+    AccountMessageImporter.import_for('whatever', 'whatever')
+  end
+
+  test 'uses the default message repository' do
+    GmailImapClient.stubs(:connect).returns(stub('gmail-client'))
+
+    message_repository = stub('message-repository')
+    importer = stub('importer')
+    MessageRepository.stubs(:instance).returns(message_repository)
+    MessageImporter.stubs(:new).returns(importer)
+    importer.expects(:import_into).with(message_repository)
+
+    AccountMessageImporter.import_for('whatever', 'whatever')
+  end
+end

test/unit/message_importer_test.rb

@@ -1,34 +1,5 @@
 require 'test_helper'
 
-class MessageImporter::WhenCoordinating < ActiveSupport::TestCase
-  test 'establishes an imap connection using the given credentials' do
-    GmailImapClient.expects(:connect).with('dave@example.com', 'password')
-    MessageImporter.stubs(:new).returns(stub_everything)
-
-    MessageImporter.import_for('dave@example.com', 'password')
-  end
-
-  test 'uses the established connection for importing' do
-    gmail_client = stub('gmail-client')
-    GmailImapClient.stubs(:connect).returns(gmail_client)
-
-    MessageImporter.expects(:new).with(gmail_client).returns(stub_everything)
-    MessageImporter.import_for('whatever', 'whatever')
-  end
-
-  test 'uses the default message repository' do
-    GmailImapClient.stubs(:connect).returns(stub('gmail-client'))
-
-    message_repository = stub('message-repository')
-    importer = stub('importer')
-    MessageRepository.stubs(:instance).returns(message_repository)
-    MessageImporter.stubs(:new).returns(importer)
-    importer.expects(:import_into).with(message_repository)
-
-    MessageImporter.import_for('whatever', 'whatever')
-  end
-end
-
 class MessageImporterTest < ActiveSupport::TestCase
   test 'imports messages' do
     gmail_client = stub('gmail-client', inbox_messages: [:message1, :message2])