I am trying to test my update method on my viewset. The viewset is a modelviewset taken from drf. To update i would need to send a put request. As this is not always supported there are 2 ways to tell the server i am making a put request, the first which does not fit my needs is to use an additional field to form called _method and set it to put. As i need to post json data i need to use the second way, which uses the X-HTTP-Method-Override header.

To post my data in the testcase i use the following code:

header = {'X_HTTP_METHOD_OVERRIDE': 'PUT'}
response = client.post('/model/1/', content_type='application/json', data=post_data_clean, **header)

But unfortunately the result I get is {'detail':'Method POST not allowed.'}. I tested the behavior of the server using a addon (Postman) where i specified the X-HTTP-Method-Override header too. No exception is raised. I need to know now how to correctly pass the header to the django test client, otherwise testing will get really annoying over here.

You need to specify header as 'HTTP_X_HTTP_METHOD_OVERRIDE' instead of 'X_HTTP_METHOD_OVERRIDE' i.e. add HTTP_ at the beginning of the header.

header = {'HTTP_X_HTTP_METHOD_OVERRIDE': 'PUT'}
response = client.post('/model/1/', content_type='application/json', data=post_data_clean, **header)

From the Django documentation:

HTTP headers in the request are converted to META keys by converting all characters to uppercase, replacing any hyphens with underscores and adding an HTTP_ prefix to the name. So, for example, a header called X-Bender would be mapped to the META key HTTP_X_BENDER.