def validate_list(obj, typ, trigger=None):
"""
Attempts to return obj as a list, each element of which has type typ.
Parameters
----------
obj: Any
Object or list of objects, all of which should be of type typ.
typ: Type
The desired type of obj, or if obj is a list, every element of obj.
trigger: function
A function to invoke when putting obj into a list.
Returns
-------
ValidList
A list with all elements of obj.
The list is constrained so that every element has type typ.
"""
if obj is None:
return ValidList([], typ, trigger)
elif isinstance(obj, list):
return ValidList(obj, typ, trigger)
else:
return ValidList([obj], typ, trigger)
def test_invalid_content():
"""Test that an invalid content_type throws a TypeError."""
with pytest.raises(TypeError):
ValidList(['z'], content_type={'types': [str]})
with pytest.raises(TypeError):
ValidList(_list=tuple([1, 1]), content_type=1)
with pytest.raises(TypeError):
ValidList(_list=tuple([1, 1]), content_type=None)
def test_triggers():
"""Tests that tiggers get fired off."""
with pytest.raises(TypeError):
ValidList(_list=tuple([1, 1]), content_type=int, trigger=1)
stash = []
def dummy(val):
stash.append(val)
with pytest.raises(TypeError):
ValidList(_list=tuple([1, 1]), trigger=dummy)
vlst = ValidList(_list=tuple([1, 1]), content_type=int, trigger=dummy)
vlst.append(1)
vlst.extend([1])
vlst.insert(2, 1)
vlst[0] = 17
assert len(vlst) == 5
assert len(stash) == 6
def test_transform():
"""Test that transformations do what we expect in changing data."""
first = [1, 2]
vlst = ValidList(first,
content_type=int,
trigger=lambda x: x + 1)
vlst.append(3)
vlst.extend([4])
vlst.insert(2, 5)
assert vlst == [2, 3, 6, 4, 5]
vlst[0] = 0
assert vlst[0] == 1
assert first == [1, 2]
def test_access_data():
"""Test that valid data can be inserted into the list and that invalid data throws an error."""
lo_strings = ValidList(['z'], str)
lo_strings[0] = 'a'
lo_strings.append('b')
lo_strings.extend(tuple(['d', 'e', 'f']))
lo_strings.insert(2, 'c')
assert lo_strings == ['a', 'b', 'c', 'd', 'e', 'f']
with pytest.raises(TypeError):
lo_strings[0] = 1
with pytest.raises(TypeError):
lo_strings.append(1)
with pytest.raises(TypeError):
lo_strings.extend(tuple([1]))
with pytest.raises(TypeError):
lo_strings.extend(1)
with pytest.raises(TypeError):
lo_strings.insert(2, 1)
lo_both = ValidList(_list=tuple([1, 'a']), content_type=[int, str])
with pytest.raises(TypeError):
lo_both[0] = 1.1