```ruby
#
# Copyright (c) 2017 Richard Delaplace
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'spec_helper'

describe 'Test file' do
  describe file('/tmp/test') do
    it { should exist }
    its(:content) { should contain 'Hello world!' }
  end
end
```

Add file tests to serverspec
user
```ruby
#
# Copyright (c) 2017 Richard Delaplace
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require 'spec_helper'

describe 'Test file' do
  describe file('/tmp/test') do
    it { should exist }
    it { should be_owned_by 'root' }
    it { should be_grouped_into 'root' }
    it { should be_mode 755 }
    its(:content) { should contain 'Hello world!' }
  end
end
```
assistant