Added better tests, and corrected documentation.

app/helpers/lfs_helper.rb

@@ -7,7 +7,7 @@ module LfsHelper
     render(
       json: {
         message: 'Git LFS is not enabled on this GitLab server, contact your admin.',
-        documentation_url: "#{Gitlab.config.gitlab.url}/help",
+        documentation_url: help_url,
       },
       status: 501
     )

doc/administration/repository_restrictions.md

 # Repository size restrictions
 
-> **Note:** Introduced with 8.12 EE
+> Introduced with GitLab Enterprise Edition 8.12
 
 Repositories within your GitLab instance can grow quickly, specially if you are
 using LFS. Their size can grow exponentially and eat up your storage device quite
@@ -23,7 +23,7 @@ new issues, and clone the project.
 
 Uploading LFS objects will also be denied.
 
-In order to lift this restrictions, the administrator of the GitLab instance
+In order to lift these restrictions, the administrator of the GitLab instance
 needs to increase the limit on the particular project that exceeded it.
 
 

spec/lib/gitlab/repository_size_error_spec.rb

+require 'spec_helper'
+
+describe Gitlab::RepositorySizeError, lib: true do
+  let(:project) { create(:empty_project, repository_size: 15) }
+  let(:message) { Gitlab::RepositorySizeError.new(project) }
+  let(:base_message) { 'because this repository has exceeded its size limit of 10 MB by 5 MB' }
+
+  before do
+    allow(project).to receive(:actual_size_limit).and_return(10)
+  end
+
+  describe 'error messages' do
+    describe '#to_s' do
+      it 'returns the correct message' do
+        expect(message.to_s).to eq('The size of this repository (15 MB) exceeds the limit of 10 MB by 5 MB.')
+      end
+    end
+
+    describe '#commit_error' do
+      it 'returns the correct message' do
+        expect(message.commit_error).to eq("Your changes could not be committed, #{base_message}")
+      end
+    end
+
+    describe '#merge_error' do
+      it 'returns the correct message' do
+        expect(message.merge_error).to eq("This merge request cannot be merged, #{base_message}")
+      end
+    end
+
+    describe '#push_error' do
+      it 'returns the correct message' do
+        expect(message.push_error).to eq("Your push has been rejected, #{base_message}. #{message.more_info_message}")
+      end
+    end
+
+    describe '#new_changes_error' do
+      it 'returns the correct message' do
+        expect(message.new_changes_error).to eq("Your push to this repository would cause it to exceed the size limit of 10 MB so it has been rejected. #{message.more_info_message}")
+      end
+    end
+  end
+end

spec/models/namespace_spec.rb

@@ -87,6 +87,18 @@ describe Namespace, models: true do
     end
   end
 
+  describe '#actual_size_limit' do
+    let(:namespace) { build(:namespace) }
+
+    before do
+      allow_any_instance_of(ApplicationSetting).to receive(:repository_size_limit).and_return(50)
+    end
+
+    it 'returns the correct size limit' do
+      expect(namespace.actual_size_limit).to eq(50)
+    end
+  end
+
   describe :rm_dir do
     let!(:project) { create(:project, namespace: namespace) }
     let!(:path) { File.join(Gitlab.config.repositories.storages.default, namespace.path) }

spec/models/project_spec.rb

@@ -486,6 +486,15 @@ describe Project, models: true do
       allow_any_instance_of(ApplicationSetting).to receive(:repository_size_limit).and_return(50)
     end
 
+    describe '#changes_will_exceed_size_limit?' do
+      before do
+        allow(project).to receive(:repository_and_lfs_size).and_return(49)
+      end
+      it 'returns true when changes go over' do
+        expect(project.changes_will_exceed_size_limit?(5)).to be_truthy
+      end
+    end
+
     describe '#actual_size_limit' do
       it 'returns the limit set in the application settings' do
         expect(project.actual_size_limit).to eq(50)

spec/services/merge_requests/merge_service_spec.rb

@@ -38,6 +38,22 @@ describe MergeRequests::MergeService, services: true do
       end
     end
 
+    context 'project has exceeded size limit' do
+      let(:service) { MergeRequests::MergeService.new(project, user, commit_message: 'Awesome message') }
+
+      before do
+        allow(project).to receive(:above_size_limit?).and_return(true)
+
+        perform_enqueued_jobs do
+          service.execute(merge_request)
+        end
+      end
+
+      it 'returns the correct error message' do
+        expect(merge_request.merge_error).to include('This merge request cannot be merged')
+      end
+    end
+
     context 'remove source branch by author' do
       let(:service) do
         merge_request.merge_params['force_remove_source_branch'] = '1'