apparently, yes. this should be fixed.

consider displaying input value instead of "One random test" for each random test.

Okay, I'll handle this special case. Okay, I'll handle this other special case. Okay...

• Removal of multiples of 0 was not mentioned in the description.

• Example and sample tests like below should be added

test.assert_equals(quadratic_builder("(x+0)(x+1)"), "x^2+x")
test.assert_equals(quadratic_builder("(2q+3)(2q-3)"), "4q^2-9")

• Description also does not mention that m and p will never be 0, also n and q can be 0

• Description should be language-agnostic (removal of function names)

This is actually an issue!

Haskell tests appear to be broken. My solution failed on the randomized tests:
Falsifiable (after 7 tests and 4 shrinks):
"aa\71319a"
expected: "a2a"
but got: "aa\71319a"
Is \71319 supposed to be a character?

There's a pattern indeed but I can't figure it out

Fixed!

Removal of multiples of 0 was not mentioned in the tasks.

ie something like 6x^2+0x-1. should become 6x^2-1.

Thanks

No, it's not available on codewars:

https://docs.codewars.com/languages/python

.

Thanks, really my bug , found an error - I missed one index

Okay so I tried your code and it seems that for the test case (-y+11)(-55y-6) your answer is y^2-5y-66, which is wrong.
The answer should be 55y^2-599y-66.
I think maybe it's caused by the "-y" in the first bracket which doesn't have a number coefficient?
By the way my test case doesn't include (y-11)(y+6).
Please check your code again and let me know if there are any further problems.