NextMock

NextMock is an enhanced mock for unittest.mock.Mock.

Features

• Argument matching supported.
• Async version (AsyncMock) provided.
• Compatible with unittest.mock.Mock.

Usage

First install nextmock from pip:

$ pip install nextmock

then import Mock for common usage, AsyncMock for async usage:

from nextmock import Mock
from nextmock import AsyncMock

API with Examples

with_args

Return/raise stub result/error only when given args are matched.

Check out /nextmock/test/test_mock_with_args.py for comprehensive exmaples.

• args matching

  m = Mock()
  
  m.with_args(1, 2, 3).returns(123)
  
  assert m(1, 2, 3) == 123
  assert m(3, 2, 1) != 123
  

• kwargs matching

  m = Mock()
  
  m.with_args(a=1, b=2, c=3).returns(123)
  
  assert m(a=1, b=2, c=3) == 123
  assert m(a=3, b=2, c=1) != 123
  

• class matching

  class Cmd:
      def __init__(self, a: int, b: str):
          self.a = a
          self.b = b
  
  m = Mock()
  
  m.with_args(Cmd(1, "123")).returns(123)
  
  assert m(Cmd(1, "123")) == 123
  assert m(Cmd(999, "321")) != 123
  

• args matcher

  from nextmock import Arg
  
  m = Mock()
  
  m.with_args(1, 2, Arg.Any).returns(123)
  
  assert m(1, 2, 1) == 123
  assert m(1, 2, 9) == 123
  assert m(1, 2, "123") == 123
  

• error raising

  m = Mock()
  
  m.with_args(1, 2, 3).raises(ValueError("value error"))
  
  with pytest.raises(ValueError) as e:
      m(1, 2, 3)
  
  assert str(e.value) == "value error"
  

• enum matching (0.0.1)

  class Category(Enum):
      A = "a"
      B = "b"
  
  m = Mock()
  
  m.with_args(Category.A).returns(123)
  
  assert m(Category.A) == 123
  assert m(Category.B) != 123
  

returns

Return stub result without matching args.

m = Mock()

m.returns(123)

assert m(1, 2, 3) == 123
assert m(a=1, b=2, c=3) == 123

raises

Raise stub error without matching args.

m = Mock()

m.raises(ValueError("value error"))

with pytest.raises(ValueError) as e:
    m(1, 2, 3)

with pytest.raises(ValueError) as e:
    m(a=1, b=2, c=3)

Compatibility

Inherit behavior from unittest.mock.Mock.

Check out /nextmock/test/test_mock_compatibility.py for comprehensive examples.

m = Mock()

m.return_value = 123

assert m(1, 2, 3) == 123

m.assert_called_once()
m.assert_called_with(1, 2, 3)

License

© Chun-Yan Ho (pilagod), 2020-NOW

Released under the MIT License