Jestspectation 1.4.3

Pattern matching tools to test complex data structures

Jestspectation

Pattern matching tools to test complex data structures.

The design is inspired by the expect system from JavaScript's Jest testing framework.

import jestspectation as expect

assert {
    "a": 1,
    "b": 2,
    "c": 3.0,
} == {
    "a": 1,
    "b": expect.Any(int),
    "c": expect.FloatApprox(2.5, magnitude=0.5)
}

Documentation

Documentation can be found on GitHub Pages.

Installation

pip install jestspectation

Usage with Pytest

The library can be used as a pytest plugin, which can give access to much more detailed error messages when assertions fail.

This should result in output similar to the following

    def test_goodbye():
>       assert 1 == expect.Any(float)
E       assert Type mismatch
E         Expected any object of type float
E         Received 1 (int)

These advanced completions can also be used for most standard Python objects by wrapping the expected values in an Equals. For example:

    def test_lists():
>       assert expect.Equals([1, 2, 3, 4]) == [1, 2, 3, 5, 6]
E       assert [1, 2, 3, 4] == [1, 2, 3, 5, 6]
E         !! [3] 4 == 5
E            Value mismatch
E            Expected 4
E            Received 5
E         ++ [4] 6

To automatically use Jestspectation's diff parsing, you can configure Jestspectation.

import jestspectation

jestspectation.configure().pytest_all_diffs = True