Safely merge two Python dictionaries

merge_dict.py

# coding: utf-8

def merge_dict(dict1, dict2):
    res = {**dict1, **dict2}
    return res

test_merge_dict.py

# coding: utf-8

import pytest

from lib.merge_dict import merge_dict


def test():
    dict1 = {"a": 1, "b": 2}
    dict2 = {"d": 4, "c": 3}  # note the swap

    result = merge_dict(dict1, dict2)
    # {"b": 2, "a": 1, "c": 3, "d": 4}
    assert sorted(result.keys()) == ["a", "b", "c", "d", ]

    assert result["a"] == 1
    assert result["b"] == 2
    assert result["c"] == 3
    assert result["d"] == 4