CODEWITHSUNDEEP
pythonjsonunit-testingflask
user3396592
user3396592

Reputation: 373

How to unit test a method that returns a JSON object?

I have two Python scripts: let's call them program.py and program_utils.py.

program.py looks like this:

from flask import Flask, request, jsonify
import program_utils

app = Flask(__name__)
@app.route('/mypage')
def my_func():
  # Do some stuff here and get a URL parameter
  my_var = request.args.get('my_var')
  # Get JSON object from another function in program_utils
  return program_utils.get_json_object(my_var)

get_json_object() in program_utils.py looks like this:

def get_json_object(my_var):
  # Do some calls to other methods to create the JSON object using my_var
  return json_object

My question is how do I create a unit test for get_json_object in program_utils to ensure that it is returning the object in the correct format? I have tried writing a regular unit test (treating the method as if it returned a string) but was presented with a run time error saying "working outside of application context".

Upvotes: 4

Views: 4703

Answers (1)

davidism
davidism

Reputation: 127190

You use the test client to test Flask views. Create it with app.test_client() and then use it to simulate requests to your routes. The response only has the raw data, if you want to compare it as JSON you'll need to load it.

c = app.test_client()
rv = c.get('/mypage', query_string={'my_var': 'my_value'})
assert json.loads(rv.get_data()) == expected_data

The Flask docs have a whole section devoted to introducing this. The Werkzeug docs go into more detail.

Upvotes: 6

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