transfer_service_spec: cleanup, merge common code, check against nil

- replace creation of group2 with the use of group without add_owner(user)
- fold TransferService calls into new test function transfer_project
  - remove currently not used (and not working) gitlab_shell stub
    (will submit testcase simulating failure in gitlab_shell separately)
- add checks against not be_nil (result.should be_false passes even if nil)

spec/services/projects/transfer_service_spec.rb

@@ -3,15 +3,12 @@ require 'spec_helper'
 describe Projects::TransferService do
   let(:user) { create(:user) }
   let(:group) { create(:group) }
-  let(:group2) { create(:group) }
   let(:project) { create(:project, namespace: user.namespace) }
 
   context 'namespace -> namespace' do
     before do
       group.add_owner(user)
-      @service = Projects::TransferService.new(project, user, namespace_id: group.id)
-      @service.gitlab_shell.stub(mv_repository: true)
-      @result = @service.execute
+      @result = transfer_project(project, user, namespace_id: group.id)
     end
 
     it { @result.should be_true }
@@ -20,24 +17,25 @@ describe Projects::TransferService do
 
   context 'namespace -> no namespace' do
     before do
-      group.add_owner(user)
-      @service = Projects::TransferService.new(project, user, namespace_id: nil)
-      @service.gitlab_shell.stub(mv_repository: true)
-      @result = @service.execute
+      @result = transfer_project(project, user, namespace_id: nil)
     end
 
+    it { @result.should_not be_nil } # { result.should be_false } passes on nil
     it { @result.should be_false }
     it { project.namespace.should == user.namespace }
   end
 
   context 'namespace -> not allowed namespace' do
     before do
-      @service = Projects::TransferService.new(project, user, namespace_id: group2.id)
-      @service.gitlab_shell.stub(mv_repository: true)
-      @result = @service.execute
+      @result = transfer_project(project, user, namespace_id: group.id)
     end
 
+    it { @result.should_not be_nil } # { result.should be_false } passes on nil
     it { @result.should be_false }
     it { project.namespace.should == user.namespace }
   end
+
+  def transfer_project(project, user, params)
+    Projects::TransferService.new(project, user, params).execute
+  end
 end