text: from flask import flash, render_template_string
  
  
  class TestMessages:
      def test_render_messages(self, app, client):
          @app.route('/messages')
          def test_messages():
              flash('test message', 'danger')
              return render_template_string('''
                              {% from 'bootstrap/utils.html' import render_messages %}
                              {{ render_messages() }}
                              ''')
  
          @app.route('/container')
          def test_container():
              flash('test message', 'danger')
              return render_template_string('''
                              {% from 'bootstrap/utils.html' import render_messages %}
                              {{ render_messages(container=True) }}
                              ''')
  
          @app.route('/dismissible')
          def test_dismissible():
              flash('test message', 'danger')
              return render_template_string('''
                              {% from 'bootstrap/utils.html' import render_messages %}
                              {{ render_messages(dismissible=True) }}
                              ''')
  
          @app.route('/dismiss_animate')
          def test_dismiss_animate():
              flash('test message', 'danger')
              return render_template_string('''
                              {% from 'bootstrap/utils.html' import render_messages %}
                              {{ render_messages(dismissible=True, dismiss_animate=True) }}
                              ''')
  
          response = client.get('/messages')
          data = response.get_data(as_text=True)
          assert '<div class="alert alert-danger"' in data
  
          response = client.get('/container')
          data = response.get_data(as_text=True)
          assert '<div class="container flashed-messages">' in data
  
          response = client.get('/dismissible')
          data = response.get_data(as_text=True)
          assert 'alert-dismissible' in data
          assert '<button type="button" class="close" data-dismiss="alert"' in data
          assert 'fade show' not in data
  
          response = client.get('/dismiss_animate')
          data = response.get_data(as_text=True)
          assert 'alert-dismissible', data
          assert '<button type="button" class="close" data-dismiss="alert"' in data
          assert 'fade show' in data
  