mmport80
I am sketching out how to test a CRUD API.
My idea is to create a simplified model / FSM, generate different states and test for properties based on the model.
E.g. assuming everything’s successful,
- GET /users
- POST /create/id/9
- DELETE /delete/id/9
- GET /users
users from 1. and 4. should be the same
Then do the a similar test when
- GET /users
- POST /create/id/8
- GET /users
3.'s users should have one more entry etc.
or when
- GET /users
- POST /create/id/11
- DELETE /delete/id/54 //:error
- GET /users
Again 4’s users should have one more entry.
basically, setting properties for as many cases I can, and then testing with random test-cases.
Problem is, I cannot find much material online, I am sure it is pretty standard esp. as CRUD APIs are pretty standard.. (?)
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idi527
I think https://propertesting.com/ is pretty good.
mmport80
I really like what I have read also - just wondering whether there is a canonical “this is how you property test a CRUD API” - these are the properties to look out for, no matter the language etc.
dimitarvp
For a server-side rendered CRUD website I’d concentrate on making
StreamDatagenerators of controller parameters – omit mandatory fields, send fields with invalid data in them, try and update or delete non-existing IDs, send fields that your app isn’t at all expecting.StreamDatacan be really alien at start but when you experiment with it for a weekend you can do some seriously powerful data generators with it!mmport80
I ended up following the book’s recommendations (https://propertesting.com/) e.g. create an ‘oracle’ state machine.
Basically, you create random states by interacting with your API and keep a record in your oracle.
You compare both oracle state and results from your API, and make sure they are always the same.
You’d be surprised the bugs you catch.. I really need to try and bundle this into a library, am sure you could test lots of apps pretty easily with one library..
axelson
Can you explain more about how you create the oracle state machine.
david_ex
From What is a Property (online version of the book, prior to having been edited):