Objects not supported in @matrix annotation

[kc596]

@confluentinc/quality-eng is tagged for visibility

Describe the bug
@matrix annotation is working only if list of primitives are used and not if list of objects are used.

To Reproduce
You can use following example to reproduce :

@dataclass
class Car:
    x: int
    y: int

@dataclass
class Bus:
    x: int
    y: int


# Declare global var of list of objects :
CARS = [Car(1,2)]
BUSES = [Bus(1,2), Bus(2,3)]

# Following annotation works :
@matrix(car_index=[0], bus_index=[0,1])
def test(self, car_index: int, bus_index: int):
    car = CARS[car_index]
    bus = BUSES[bus_index]

# However, this one is not working :
@matrix(car=CARS, bus=BUSES)
def test(self, car: Car, bus: Bus):
    pass

Expected behavior
The tests should work even when list of objects are passed into @matrix.

[imcdo]

I Don't agree with this, as arguments should be always json serializable, so they can be passed in via the command line if someone wants to use the exact params.

[stan-is-hate]

+1 to @imcdo , ducktape needs to keep any paramters json-serializable, otherwise it breaks existing functionality.

[stan-is-hate]

If your objects are json-serializable though, I think I've seen them work with parameterized tests