Test Flask render_template() context

Question

I have a Flask route that looks like this:

@app.route('/')                                                                 
def home():                                                                                                                  
    return render_template(                                                     
        'home.html',                                                            
        greeting:"hello"                                       
    )                                                                           

How do I test that the 'home.html' template was rendered, and that the render_template() context defined the greeting variable with a particular value?

These should be (and probably are) pretty easy to test, but I'm really not sure how to do this with Flask and unittest.

Answer 1

You can use the assert_template_used method of TestCase provided by flask-testing.

from flask.ext.testing import TestCase

class MyTest(TestCase):

    def create_app(self):
        return myflaskapp

    def test_greeting(self):
        self.app.get('/')
        self.assert_template_used('hello.html')
        self.assert_context("greeting", "hello")

The method create_app must provide your flask app.