Add specs for MergeRequests::BuildService

spec/services/merge_requests/build_service_spec.rb

+require 'spec_helper'
+
+describe MergeRequests::BuildService, services: true do
+  include RepoHelpers
+
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+  let(:issue) { create(:issue, project: project) }
+  let(:description) { nil }
+  let(:source_branch) { 'feature-branch' }
+  let(:target_branch) { 'master' }
+  let(:merge_request) { service.execute }
+  let(:compare) { double(:compare, commits: commits) }
+  let(:commit_1) { double(:commit_1, safe_message: "Initial commit\n\nCreate the app") }
+  let(:commit_2) { double(:commit_2, safe_message: 'This is a bad commit message!') }
+  let(:commits) { nil }
+
+  let(:service) do
+    MergeRequests::BuildService.new(project, user,
+                                    description: description,
+                                    source_branch: source_branch,
+                                    target_branch: target_branch)
+  end
+
+  before do
+    allow(CompareService).to receive_message_chain(:new, :execute).and_return(compare)
+  end
+
+  describe 'execute' do
+    context 'missing source branch' do
+      let(:source_branch) { '' }
+
+      it 'forbids the merge request from being created' do
+        expect(merge_request.can_be_created).to eq(false)
+      end
+
+      it 'adds an error message to the merge request' do
+        expect(merge_request.errors).to contain_exactly('You must select source and target branch')
+      end
+    end
+
+    context 'missing target branch' do
+      let(:target_branch) { '' }
+
+      it 'forbids the merge request from being created' do
+        expect(merge_request.can_be_created).to eq(false)
+      end
+
+      it 'adds an error message to the merge request' do
+        expect(merge_request.errors).to contain_exactly('You must select source and target branch')
+      end
+    end
+
+    context 'no commits in the diff' do
+      let(:commits) { [] }
+
+      it 'forbids the merge request from being created' do
+        expect(merge_request.can_be_created).to eq(false)
+      end
+    end
+
+    context 'one commit in the diff' do
+      let(:commits) { [commit_1] }
+
+      it 'allows the merge request to be created' do
+        expect(merge_request.can_be_created).to eq(true)
+      end
+
+      it 'uses the title of the commit as the title of the merge request' do
+        expect(merge_request.title).to eq(commit_1.safe_message.split("\n").first)
+      end
+
+      it 'uses the description of the commit as the description of the merge request' do
+        expect(merge_request.description).to eq(commit_1.safe_message.split(/\n+/, 2).last)
+      end
+
+      context 'merge request already has a description set' do
+        let(:description) { 'Merge request description' }
+
+        it 'keeps the description from the initial params' do
+          expect(merge_request.description).to eq(description)
+        end
+      end
+
+      context 'commit has no description' do
+        let(:commits) { [commit_2] }
+
+        it 'uses the title of the commit as the title of the merge request' do
+          expect(merge_request.title).to eq(commit_2.safe_message)
+        end
+
+        it 'sets the description to nil' do
+          expect(merge_request.description).to be_nil
+        end
+      end
+
+      context 'branch starts with issue IID followed by a hyphen' do
+        let(:source_branch) { "#{issue.iid}-fix-issue" }
+
+        it 'appends "Closes #$issue-iid" to the description' do
+          expect(merge_request.description).to eq("#{commit_1.safe_message.split(/\n+/, 2).last}\nCloses ##{issue.iid}")
+        end
+
+        context 'merge request already has a description set' do
+          let(:description) { 'Merge request description' }
+
+          it 'appends "Closes #$issue-iid" to the description' do
+            expect(merge_request.description).to eq("#{description}\nCloses ##{issue.iid}")
+          end
+        end
+
+        context 'commit has no description' do
+          let(:commits) { [commit_2] }
+
+          it 'sets the description to "Closes #$issue-iid"' do
+            expect(merge_request.description).to eq("Closes ##{issue.iid}")
+          end
+        end
+      end
+    end
+
+    context 'more than one commit in the diff' do
+      let(:commits) { [commit_1, commit_2] }
+
+      it 'allows the merge request to be created' do
+        expect(merge_request.can_be_created).to eq(true)
+      end
+
+      it 'uses the title of the branch as the merge request title' do
+        expect(merge_request.title).to eq('Feature branch')
+      end
+
+      it 'does not add a description' do
+        expect(merge_request.description).to be_nil
+      end
+
+      context 'merge request already has a description set' do
+        let(:description) { 'Merge request description' }
+
+        it 'keeps the description from the initial params' do
+          expect(merge_request.description).to eq(description)
+        end
+      end
+    end
+  end
+end