def test_dict_merge_immutable():
"""ensure dict merge is non-destructive/immutable."""
x1 = {'one': 1, 'two': 2}
x1_cop = x1.copy()
ir.dict_merge(x1, {'three': 3, 'two': None})
assert x1 == x1_cop
ir.dict_merge({'ten': 10, 'one': '1'}, x1)
assert x1 == x1_cop
def test_dict_merge_three():
new_dict = ir.dict_merge({
'one': 1,
'two': 2
}, {'three': 3}, {
'four': 4,
'five': 5
})
assert new_dict == {'one': 1, 'two': 2, 'three': 3, 'four': 4, 'five': 5}
def test_dict_merge_pair():
x1 = {'one': 1, 'two': '2'}
x2 = {'two': 2, 'three': 3}
assert ir.dict_merge(x1, x2) == {'one': 1, 'two': 2, 'three': 3}
def test_dict_merge_empty():
x1 = {'one': 1, 'two': 2}
assert ir.dict_merge(x1, {}) == x1
assert ir.dict_merge({}, x1) == x1
def test_dict_merge_precedence():
x1 = {'one': 1, 'two': '2'}
x2 = {'two': 2, 'three': 3}
assert ir.dict_merge(x1, x2)['two'] == 2
assert ir.dict_merge(x2, x1)['two'] == '2'