Improve small details in specs:

* Fix coding standards;
* Simplify some expectations (eq instead of be matcher);
* Expect identity on block instead of calling;
* Change some before call as oneliners;
* Avoid shadowing variable names;
* Improve wording where needed.

spec/producer/core/remote/fs_spec.rb

@@ -15,12 +15,12 @@ module Producer::Core
       before { sftp_story }
 
       it 'builds a new SFTP session' do
-        expect(remote.session.sftp).to receive(:connect)
+        expect(remote.session.sftp).to receive :connect
         fs.sftp
       end
 
       it 'returns the new SFTP session' do
-        session = double('session')
+        session = double 'session'
         allow(remote.session.sftp).to receive(:connect) { session }
         expect(fs.sftp).to be session
       end
@@ -35,7 +35,7 @@ module Producer::Core
     # part of net-ssh story helpers, which are more close to integration tests.
     describe '#has_file?', :ssh do
       let(:file_path) { "some_file_path" }
-      let(:stat)      { double('stat') }
+      let(:stat)      { double 'stat' }
 
       before do
         sftp_story
@@ -44,35 +44,31 @@ module Producer::Core
 
       context 'when path given as argument exists' do
         context 'when path is a file' do
-          before do
-            allow(stat).to receive(:file?) { true }
-          end
+          before { allow(stat).to receive(:file?) { true } }
 
           it 'returns true' do
-            expect(fs.has_file?(file_path)).to be true
+            expect(fs.has_file? file_path).to be true
           end
         end
 
         context 'when path is not a file' do
-          before do
-            allow(stat).to receive(:file?) { false }
-          end
+          before { allow(stat).to receive(:file?) { false } }
 
           it 'returns false' do
-            expect(fs.has_file?(file_path)).to be false
+            expect(fs.has_file? file_path).to be false
           end
         end
       end
 
       context 'when querying the path raises a Net::SFTP::StatusException' do
         before do
-          response = double('response', code: '42', message: 'some message')
+          response = double 'response', code: '42', message: 'some message'
           ex = Net::SFTP::StatusException.new(response)
           allow(stat).to receive(:file?).and_raise(ex)
         end
 
         it 'returns false' do
-          expect(fs.has_file?(file_path)).to be false
+          expect(fs.has_file? file_path).to be false
         end
       end
     end