from collections.abc import Sequence

from typing import Any

import pytest

import matplotlib as mpl

from matplotlib.backends import BackendFilter, backend_registry

@pytest.fixture

def clear_backend_registry():

# Fixture that clears the singleton backend_registry before and after use

# so that the test state remains isolated.

backend_registry._clear()

yield

backend_registry._clear()

def has_duplicates(seq: Sequence[Any]) -> bool:

return len(seq) > len(set(seq))

@pytest.mark.parametrize(

'framework,expected',

[

('qt', 'qtagg'),

('gtk3', 'gtk3agg'),

('gtk4', 'gtk4agg'),

('wx', 'wxagg'),

('tk', 'tkagg'),

('macosx', 'macosx'),

('headless', 'agg'),

('does not exist', None),

]

)

def test_backend_for_gui_framework(framework, expected):

assert backend_registry.backend_for_gui_framework(framework) == expected

def test_list_builtin():

backends = backend_registry.list_builtin()

assert not has_duplicates(backends)

# Compare using sets as order is not important

assert {*backends} == {

'gtk3agg', 'gtk3cairo', 'gtk4agg', 'gtk4cairo', 'macosx', 'nbagg', 'notebook',

'qtagg', 'qtcairo', 'qt5agg', 'qt5cairo', 'tkagg',

'tkcairo', 'webagg', 'wx', 'wxagg', 'wxcairo', 'agg', 'cairo', 'pdf', 'pgf',

'ps', 'svg', 'template',

}

@pytest.mark.parametrize(

'filter,expected',

[

(BackendFilter.INTERACTIVE,

['gtk3agg', 'gtk3cairo', 'gtk4agg', 'gtk4cairo', 'macosx', 'nbagg', 'notebook',

'qtagg', 'qtcairo', 'qt5agg', 'qt5cairo', 'tkagg',

'tkcairo', 'webagg', 'wx', 'wxagg', 'wxcairo']),

(BackendFilter.NON_INTERACTIVE,

['agg', 'cairo', 'pdf', 'pgf', 'ps', 'svg', 'template']),

]

)

def test_list_builtin_with_filter(filter, expected):

backends = backend_registry.list_builtin(filter)

assert not has_duplicates(backends)

# Compare using sets as order is not important

assert {*backends} == {*expected}

def test_list_gui_frameworks():

frameworks = backend_registry.list_gui_frameworks()

assert not has_duplicates(frameworks)

# Compare using sets as order is not important

assert {*frameworks} == {

"gtk3", "gtk4", "macosx", "qt", "qt5", "qt6", "tk", "wx",

}

@pytest.mark.parametrize("backend, is_valid", [

("agg", True),

("QtAgg", True),

("module://anything", True),

("made-up-name", False),

])

def test_is_valid_backend(backend, is_valid):

assert backend_registry.is_valid_backend(backend) == is_valid

@pytest.mark.parametrize("backend, normalized", [

("agg", "matplotlib.backends.backend_agg"),

("QtAgg", "matplotlib.backends.backend_qtagg"),

("module://Anything", "Anything"),

])

def test_backend_normalization(backend, normalized):

assert backend_registry._backend_module_name(backend) == normalized

def test_deprecated_rcsetup_attributes():

match = "was deprecated in Matplotlib 3.9"

with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):

mpl.rcsetup.interactive_bk

with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):

mpl.rcsetup.non_interactive_bk

with pytest.warns(mpl.MatplotlibDeprecationWarning, match=match):

mpl.rcsetup.all_backends

def test_entry_points_inline():

pytest.importorskip('matplotlib_inline')

backends = backend_registry.list_all()

assert 'inline' in backends

def test_entry_points_ipympl():

pytest.importorskip('ipympl')

backends = backend_registry.list_all()

assert 'ipympl' in backends

assert 'widget' in backends

def test_entry_point_name_shadows_builtin(clear_backend_registry):

with pytest.raises(RuntimeError):

backend_registry._validate_and_store_entry_points(

[('qtagg', 'module1')])

def test_entry_point_name_duplicate(clear_backend_registry):

with pytest.raises(RuntimeError):

backend_registry._validate_and_store_entry_points(

[('some_name', 'module1'), ('some_name', 'module2')])

def test_entry_point_identical(clear_backend_registry):

# Issue https://github.com/matplotlib/matplotlib/issues/28367

# Multiple entry points with the same name and value (value is the module)

# are acceptable.

n = len(backend_registry._name_to_module)

backend_registry._validate_and_store_entry_points(

[('some_name', 'some.module'), ('some_name', 'some.module')])

assert len(backend_registry._name_to_module) == n+1

assert backend_registry._name_to_module['some_name'] == 'module://some.module'

def test_entry_point_name_is_module(clear_backend_registry):

with pytest.raises(RuntimeError):

backend_registry._validate_and_store_entry_points(

[('module://backend.something', 'module1')])

@pytest.mark.parametrize('backend', [

'agg',

'module://matplotlib.backends.backend_agg',

])

def test_load_entry_points_only_if_needed(clear_backend_registry, backend):

assert not backend_registry._loaded_entry_points

check = backend_registry.resolve_backend(backend)

assert check == (backend, None)

assert not backend_registry._loaded_entry_points

backend_registry.list_all() # Force load of entry points

assert backend_registry._loaded_entry_points

@pytest.mark.parametrize(

'gui_or_backend, expected_backend, expected_gui',

[

('agg', 'agg', None),

('qt', 'qtagg', 'qt'),

('TkCairo', 'tkcairo', 'tk'),

]

)

def test_resolve_gui_or_backend(gui_or_backend, expected_backend, expected_gui):

backend, gui = backend_registry.resolve_gui_or_backend(gui_or_backend)

assert backend == expected_backend

assert gui == expected_gui

def test_resolve_gui_or_backend_invalid():

match = "is not a recognised GUI loop or backend name"

with pytest.raises(RuntimeError, match=match):

backend_registry.resolve_gui_or_backend('no-such-name')