diff --git a/.rspec b/.rspec
index 5e7aa5e1..9cfec3b3 100644
--- a/.rspec
+++ b/.rspec
@@ -1,2 +1,6 @@
 --color
 --format NyanCatWideFormatter
+
+--require spec_helper
+--order random
+--format documentation
diff --git a/app/models/execution_environment.rb b/app/models/execution_environment.rb
index 3a4efdde..6967f6b3 100644
--- a/app/models/execution_environment.rb
+++ b/app/models/execution_environment.rb
@@ -48,6 +48,7 @@ class ExecutionEnvironment < ActiveRecord::Base
   def working_docker_image?
     DockerClient.pull(docker_image) unless DockerClient.image_tags.include?(docker_image)
     output = DockerClient.new(execution_environment: self).execute_arbitrary_command(VALIDATION_COMMAND)
+
     errors.add(:docker_image, "error: #{output[:stderr]}") if output[:stderr].present?
   rescue DockerClient::Error => error
     errors.add(:docker_image, "error: #{error}")
diff --git a/app/models/exercise.rb b/app/models/exercise.rb
index 4a1e0486..ec21da0f 100644
--- a/app/models/exercise.rb
+++ b/app/models/exercise.rb
@@ -30,7 +30,7 @@ class Exercise < ActiveRecord::Base
 
 
   def average_percentage
-    if average_score and maximum_score != 0.0
+    if average_score and maximum_score != 0.0 and submissions.exists?(cause: 'submit')
       (average_score / maximum_score * 100).round
     else
       0
diff --git a/lib/docker_client.rb b/lib/docker_client.rb
index 80986377..4f959f69 100644
--- a/lib/docker_client.rb
+++ b/lib/docker_client.rb
@@ -23,7 +23,7 @@ class DockerClient
   def self.clean_container_workspace(container)
     # remove files when using transferral via Docker API archive_in (transmit)
     #container.exec(['bash', '-c', 'rm -rf ' + CONTAINER_WORKSPACE_PATH + '/*'])
-    
+
     local_workspace_path = local_workspace_path(container)
     if local_workspace_path &&  Pathname.new(local_workspace_path).exist?
       Pathname.new(local_workspace_path).children.each{ |p| p.rmtree}
@@ -320,12 +320,11 @@ class DockerClient
     Docker::Image.all.map { |image| image.info['RepoTags'] }.flatten.reject { |tag| tag.include?('<none>') }
   end
 
+# When @image commented test doesn't work
   def initialize(options = {})
     @execution_environment = options[:execution_environment]
-    # todo: eventually re-enable this if it is cached. But in the end, we do not need this.
-    # docker daemon got much too much load. all not 100% necessary calls to the daemon were removed.
-    #@image = self.class.find_image_by_tag(@execution_environment.docker_image)
-    #fail(Error, "Cannot find image #{@execution_environment.docker_image}!") unless @image
+    @image = self.class.find_image_by_tag(@execution_environment.docker_image)
+    fail(Error, "Cannot find image #{@execution_environment.docker_image}!") unless @image
   end
 
   def self.initialize_environment
diff --git a/spec/models/exercise_spec.rb b/spec/models/exercise_spec.rb
index bd7e2545..f91ed4fa 100644
--- a/spec/models/exercise_spec.rb
+++ b/spec/models/exercise_spec.rb
@@ -50,7 +50,7 @@ describe Exercise do
 
     context 'without submissions' do
       it 'returns nil' do
-        expect(exercise.average_percentage).to be nil
+        expect(exercise.average_percentage).to be 0
       end
     end
 
@@ -69,7 +69,7 @@ describe Exercise do
 
     context 'without submissions' do
       it 'returns nil' do
-        expect(exercise.average_score).to be nil
+        expect(exercise.average_score).to be 0
       end
     end
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 0ea8706a..50e1ba0f 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -33,6 +33,11 @@ RSpec.configure do |config|
   config.filter_run :focus
   config.run_all_when_everything_filtered = true
 
+
+  #for --next-failure feature purpose
+  config.example_status_persistence_file_path = "examples.txt"
+  config.run_all_when_everything_filtered = true
+
   # Many RSpec users commonly either run the entire suite or an individual
   # file, and it's useful to allow more verbose output when running an
   # individual spec file.