Testing in Graphene

Automated testing is an extremely useful bug-killing tool for the modern developer. You can use a collection of tests – a test suite – to solve, or avoid, a number of problems:

  • When you’re writing new code, you can use tests to validate your code works as expected.

  • When you’re refactoring or modifying old code, you can use tests to ensure your changes haven’t affected your application’s behavior unexpectedly.

Testing a GraphQL application is a complex task, because a GraphQL application is made of several layers of logic – schema definition, schema validation, permissions and field resolution.

With Graphene test-execution framework and assorted utilities, you can simulate GraphQL requests, execute mutations, inspect your application’s output and generally verify your code is doing what it should be doing.

Testing tools

Graphene provides a small set of tools that come in handy when writing tests.

Test Client

The test client is a Python class that acts as a dummy GraphQL client, allowing you to test your views and interact with your Graphene-powered application programmatically.

Some of the things you can do with the test client are:

  • Simulate Queries and Mutations and observe the response.

  • Test that a given query request is rendered by a given Django template, with a template context that contains certain values.

Overview and a quick example

To use the test client, instantiate graphene.test.Client and retrieve GraphQL responses:

from graphene.test import Client

def test_hey():
    client = Client(my_schema)
    executed = client.execute('''{ hey }''')
    assert executed == {
        'data': {
            'hey': 'hello!'
        }
    }

Execute parameters

You can also add extra keyword arguments to the execute method, such as context, root, variables, …:

from graphene.test import Client

def test_hey():
    client = Client(my_schema)
    executed = client.execute('''{ hey }''', context={'user': 'Peter'})
    assert executed == {
        'data': {
            'hey': 'hello Peter!'
        }
    }