Mocking

bunpy.mock provides mock, spy, and stub utilities for replacing implementations during tests.

mock.fn

Create a mock function that records calls:

from bunpy.mock import fn

add = fn(lambda a, b: a + b)

result = add(1, 2)

assert add.mock.calls == [[1, 2]]
assert add.mock.results == [3]
assert add.mock.call_count == 1

mock.spyOn

Wrap an existing method and record calls without changing behaviour:

from bunpy.mock import spyOn
import os

spy = spyOn(os.path, "exists")

os.path.exists("/tmp")

assert spy.mock.call_count == 1
spy.mockRestore()   # restore the original

mock.module

Replace an entire module with a stub for the duration of a test:

from bunpy.mock import module as mockModule
from bunpy.test import test, expect

@test("calls external API")
def _():
    with mockModule("requests") as m:
        m.get.return_value.status_code = 200
        import myapp.client
        resp = myapp.client.fetch_data()
        expect(resp["status"]).to_be(200)

mockReturnValue

Override the return value without changing the call recording:

get = fn()
get.mockReturnValue(42)

assert get() == 42
assert get.mock.call_count == 1

mockImplementation

Swap the implementation dynamically:

greet = fn(lambda name: f"Hello, {name}!")
greet.mockImplementation(lambda name: f"Hi, {name}!")

assert greet("Alice") == "Hi, Alice!"

Clearing mocks

add.mockClear()   # resets call count and history
add.mockReset()   # also resets return value and implementation

Snapshots