Change the order of the access rules to check simpler first, and add specs

lib/gitlab/checks/change_access.rb

@@ -11,7 +11,7 @@ module Gitlab
       end
 
       def exec
-        error = protected_branch_checks || tag_checks || push_checks
+        error = push_checks || tag_checks || protected_branch_checks
 
         if error
           GitAccessStatus.new(false, error)

spec/lib/gitlab/checks/change_access_spec.rb

@@ -0,0 +1,99 @@
+require 'spec_helper'
+
+describe Gitlab::Checks::ChangeAccess, lib: true do
+  describe '#exec' do
+    let(:user) { create(:user) }
+    let(:project) { create(:project) }
+    let(:user_access) { Gitlab::UserAccess.new(user, project: project) }
+    let(:changes) do
+      {
+        oldrev: 'be93687618e4b132087f430a4d8fc3a609c9b77c',
+        newrev: '54fcc214b94e78d7a41a9a8fe6d87a5e59500e51',
+        ref: 'refs/heads/master'
+      }
+    end
+
+    subject { described_class.new(changes, project: project, user_access: user_access).exec }
+
+    before { allow(user_access).to receive(:can_do_action?).with(:push_code).and_return(true) }
+
+    context 'without failed checks' do
+      it "doesn't return any error" do
+        expect(subject.status).to be(true)
+      end
+    end
+
+    context 'when the user is not allowed to push code' do
+      it 'returns an error' do
+        expect(user_access).to receive(:can_do_action?).with(:push_code).and_return(false)
+
+        expect(subject.status).to be(false)
+        expect(subject.message).to eq('You are not allowed to push code to this project.')
+      end
+    end
+
+    context 'tags check' do
+      let(:changes) do
+        {
+          oldrev: 'be93687618e4b132087f430a4d8fc3a609c9b77c',
+          newrev: '54fcc214b94e78d7a41a9a8fe6d87a5e59500e51',
+          ref: 'refs/tags/v1.0.0'
+        }
+      end
+
+      it 'returns an error if the user is not allowed to update tags' do
+        expect(user_access).to receive(:can_do_action?).with(:admin_project).and_return(false)
+
+        expect(subject.status).to be(false)
+        expect(subject.message).to eq('You are not allowed to change existing tags on this project.')
+      end
+    end
+
+    context 'protected branches check' do
+      before do
+        allow(project).to receive(:protected_branch?).with('master').and_return(true)
+      end
+
+      it 'returns an error if the user is not allowed to do forced pushes to protected branches' do
+        expect(Gitlab::Checks::ForcePush).to receive(:force_push?).and_return(true)
+        expect(user_access).to receive(:can_do_action?).with(:force_push_code_to_protected_branches).and_return(false)
+
+        expect(subject.status).to be(false)
+        expect(subject.message).to eq('You are not allowed to force push code to a protected branch on this project.')
+      end
+
+      it 'returns an error if the user is not allowed to merge to protected branches' do
+        expect_any_instance_of(Gitlab::Checks::MatchingMergeRequest).to receive(:match?).and_return(true)
+        expect(user_access).to receive(:can_merge_to_branch?).and_return(false)
+        expect(user_access).to receive(:can_push_to_branch?).and_return(false)
+
+        expect(subject.status).to be(false)
+        expect(subject.message).to eq('You are not allowed to merge code into protected branches on this project.')
+      end
+
+      it 'returns an error if the user is not allowed to push to protected branches' do
+        expect(user_access).to receive(:can_push_to_branch?).and_return(false)
+
+        expect(subject.status).to be(false)
+        expect(subject.message).to eq('You are not allowed to push code to protected branches on this project.')
+      end
+
+      context 'branch deletion' do
+        let(:changes) do
+          {
+            oldrev: 'be93687618e4b132087f430a4d8fc3a609c9b77c',
+            newrev: '0000000000000000000000000000000000000000',
+            ref: 'refs/heads/master'
+          }
+        end
+
+        it 'returns an error if the user is not allowed to delete protected branches' do
+          expect(user_access).to receive(:can_do_action?).with(:remove_protected_branches).and_return(false)
+
+          expect(subject.status).to be(false)
+          expect(subject.message).to eq('You are not allowed to delete protected branches from this project.')
+        end
+      end
+    end
+  end
+end