Change minimum parallel value to 2

lib/gitlab/ci/config/entry/job.rb

@@ -28,7 +28,7 @@ module Gitlab
                                                 greater_than_or_equal_to: 0,
                                                 less_than_or_equal_to: 2 }
               validates :parallel, numericality: { only_integer: true,
-                                                   greater_than_or_equal_to: 1 }
+                                                   greater_than_or_equal_to: 2 }
               validates :when,
                 inclusion: { in: %w[on_success on_failure always manual delayed],
                              message: 'should be on_success, on_failure, ' \

spec/lib/gitlab/ci/config/entry/job_spec.rb

@@ -147,13 +147,13 @@ describe Gitlab::Ci::Config::Entry::Job do
           end
         end
 
-        context 'when it is lower than one' do
-          let(:config) { { parallel: 0 } }
+        context 'when it is lower than two' do
+          let(:config) { { parallel: 1 } }
 
           it 'returns error about value too low' do
             expect(entry).not_to be_valid
             expect(entry.errors)
-              .to include 'job parallel must be greater than or equal to 1'
+              .to include 'job parallel must be greater than or equal to 2'
           end
         end
 

spec/lib/gitlab/ci/yaml_processor_spec.rb

@@ -141,11 +141,11 @@ module Gitlab
           context 'when parallel is defined' do
             let(:config) do
               YAML.dump(rspec: { script: 'rspec',
-                                 parallel: 1 })
+                                 parallel: 2 })
             end
 
             it 'has the attributes' do
-              expect(subject[:options][:parallel]).to eq 1
+              expect(subject[:options][:parallel]).to eq 2
             end
           end
         end