is it possible to overwrite parameters in a called feature file, which have been defined in background or scenario? - karate

Question

https://github.com/intuit/karate#calling-other-feature-files
The link above contains an example of calling a feature file in order to reuse the code. The feature file which is reused is called with the inputs
Background:
* configure headers = read('classpath:my-headers.js')
* def signIn = call read('classpath:my-signin.feature') { username:'john', password: 'secret' }
* def authToken = signIn.authToken
The called my-signin.feature:
Scenario:
Given url loginUrlBase
And request { userId: '#(username)', userPass: '#(password)' }
When method post
Then status 200
And def authToken = response
...
In this example the my-signin.feature must be run with the inputs username and password. I know that if you had the following:
Background:
* def username = "foo"
* def password = "secret"
at the top of the my-signing.feature file, the parameters input by the feature attempting to reuse the feature file would be overwritten.
My question is:
If reuse is the main interest of being able to call other feature files, is there a way to have the calling feature file overwrite the username and password parameters if they had been defined in the background?
It seems to me that having the background overwrite the input parameters instead of vice versa makes it harder to reuse *.feature files. I know I found it a little frustrating on my project not being able to reuse tests I had already written without refactoring out the reusable code into another file.

Answer 1

Any called feature in karate will have a magic variable __arg, you can check for this before assigning values to your variables in your called script.
Background:
* def username = (__arg == null) ? "foo" : __arg.username
* def password = (__arg == null)? "secret" : __arg.password
this will check for values passed,
if none passed it will assign default
* def signIn = call read('classpath:my-signin.feature')
if passed with arguments passed arguments will be assigned
* def signIn = call read('classpath:my-signin.feature') { username: 'notfoo', password: 'notsecret' }
For simplicity don't have anyother parameters that need to passed other than this.