2.0

1 files changed, 187 insertions, 0 deletions

diff --git a/.venv/lib/python3.12/site-packages/networkx/utils/tests/test_backends.py b/.venv/lib/python3.12/site-packages/networkx/utils/tests/test_backends.py
new file mode 100644
index 0000000..fb0309c
--- /dev/null
+++ b/.venv/lib/python3.12/site-packages/networkx/utils/tests/test_backends.py
@@ -0,0 +1,187 @@
+import pickle
+
+import pytest
+
+import networkx as nx
+
+sp = pytest.importorskip("scipy")
+pytest.importorskip("numpy")
+
+
+@nx._dispatchable(implemented_by_nx=False)
+def _stub_func(G):
+    raise NotImplementedError("_stub_func is a stub")
+
+
+def test_dispatch_kwds_vs_args():
+    G = nx.path_graph(4)
+    nx.pagerank(G)
+    nx.pagerank(G=G)
+    with pytest.raises(TypeError):
+        nx.pagerank()
+
+
+def test_pickle():
+    count = 0
+    for name, func in nx.utils.backends._registered_algorithms.items():
+        pickled = pickle.dumps(func.__wrapped__)
+        assert pickle.loads(pickled) is func.__wrapped__
+        try:
+            # Some functions can't be pickled, but it's not b/c of _dispatchable
+            pickled = pickle.dumps(func)
+        except pickle.PicklingError:
+            continue
+        assert pickle.loads(pickled) is func
+        count += 1
+    assert count > 0
+    assert pickle.loads(pickle.dumps(nx.inverse_line_graph)) is nx.inverse_line_graph
+
+
+@pytest.mark.skipif(
+    "not nx.config.backend_priority.algos "
+    "or nx.config.backend_priority.algos[0] != 'nx_loopback'"
+)
+def test_graph_converter_needs_backend():
+    # When testing, `nx.from_scipy_sparse_array` will *always* call the backend
+    # implementation if it's implemented. If `backend=` isn't given, then the result
+    # will be converted back to NetworkX via `convert_to_nx`.
+    # If not testing, then calling `nx.from_scipy_sparse_array` w/o `backend=` will
+    # always call the original version. `backend=` is *required* to call the backend.
+    from networkx.classes.tests.dispatch_interface import (
+        LoopbackBackendInterface,
+        LoopbackGraph,
+    )
+
+    A = sp.sparse.coo_array([[0, 3, 2], [3, 0, 1], [2, 1, 0]])
+
+    side_effects = []
+
+    def from_scipy_sparse_array(self, *args, **kwargs):
+        side_effects.append(1)  # Just to prove this was called
+        return self.convert_from_nx(
+            self.__getattr__("from_scipy_sparse_array")(*args, **kwargs),
+            preserve_edge_attrs=True,
+            preserve_node_attrs=True,
+            preserve_graph_attrs=True,
+        )
+
+    @staticmethod
+    def convert_to_nx(obj, *, name=None):
+        if type(obj) is nx.Graph:
+            return obj
+        return nx.Graph(obj)
+
+    # *This mutates LoopbackBackendInterface!*
+    orig_convert_to_nx = LoopbackBackendInterface.convert_to_nx
+    LoopbackBackendInterface.convert_to_nx = convert_to_nx
+    LoopbackBackendInterface.from_scipy_sparse_array = from_scipy_sparse_array
+
+    try:
+        assert side_effects == []
+        assert type(nx.from_scipy_sparse_array(A)) is nx.Graph
+        assert side_effects == [1]
+        assert (
+            type(nx.from_scipy_sparse_array(A, backend="nx_loopback")) is LoopbackGraph
+        )
+        assert side_effects == [1, 1]
+        # backend="networkx" is default implementation
+        assert type(nx.from_scipy_sparse_array(A, backend="networkx")) is nx.Graph
+        assert side_effects == [1, 1]
+    finally:
+        LoopbackBackendInterface.convert_to_nx = staticmethod(orig_convert_to_nx)
+        del LoopbackBackendInterface.from_scipy_sparse_array
+    with pytest.raises(ImportError, match="backend is not installed"):
+        nx.from_scipy_sparse_array(A, backend="bad-backend-name")
+
+
+@pytest.mark.skipif(
+    "not nx.config.backend_priority.algos "
+    "or nx.config.backend_priority.algos[0] != 'nx_loopback'"
+)
+def test_networkx_backend():
+    """Test using `backend="networkx"` in a dispatchable function."""
+    # (Implementing this test is harder than it should be)
+    from networkx.classes.tests.dispatch_interface import (
+        LoopbackBackendInterface,
+        LoopbackGraph,
+    )
+
+    G = LoopbackGraph()
+    G.add_edges_from([(0, 1), (1, 2), (1, 3), (2, 4)])
+
+    @staticmethod
+    def convert_to_nx(obj, *, name=None):
+        if isinstance(obj, LoopbackGraph):
+            new_graph = nx.Graph()
+            new_graph.__dict__.update(obj.__dict__)
+            return new_graph
+        return obj
+
+    # *This mutates LoopbackBackendInterface!*
+    # This uses the same trick as in the previous test.
+    orig_convert_to_nx = LoopbackBackendInterface.convert_to_nx
+    LoopbackBackendInterface.convert_to_nx = convert_to_nx
+    try:
+        G2 = nx.ego_graph(G, 0, backend="networkx")
+        assert type(G2) is nx.Graph
+    finally:
+        LoopbackBackendInterface.convert_to_nx = staticmethod(orig_convert_to_nx)
+
+
+def test_dispatchable_are_functions():
+    assert type(nx.pagerank) is type(nx.pagerank.orig_func)
+
+
+@pytest.mark.skipif("not nx.utils.backends.backends")
+def test_mixing_backend_graphs():
+    from networkx.classes.tests import dispatch_interface
+
+    G = nx.Graph()
+    G.add_edge(1, 2)
+    G.add_edge(2, 3)
+    H = nx.Graph()
+    H.add_edge(2, 3)
+    rv = nx.intersection(G, H)
+    assert set(nx.intersection(G, H)) == {2, 3}
+    G2 = dispatch_interface.convert(G)
+    H2 = dispatch_interface.convert(H)
+    if "nx_loopback" in nx.config.backend_priority:
+        # Auto-convert
+        assert set(nx.intersection(G2, H)) == {2, 3}
+        assert set(nx.intersection(G, H2)) == {2, 3}
+    elif not nx.config.backend_priority and "nx_loopback" not in nx.config.backends:
+        # G2 and H2 are backend objects for a backend that is not registered!
+        with pytest.raises(ImportError, match="backend is not installed"):
+            nx.intersection(G2, H)
+        with pytest.raises(ImportError, match="backend is not installed"):
+            nx.intersection(G, H2)
+    # It would be nice to test passing graphs from *different* backends,
+    # but we are not set up to do this yet.
+
+
+def test_bad_backend_name():
+    """Using `backend=` raises with unknown backend even if there are no backends."""
+    with pytest.raises(
+        ImportError, match="'this_backend_does_not_exist' backend is not installed"
+    ):
+        nx.null_graph(backend="this_backend_does_not_exist")
+
+
+def test_not_implemented_by_nx():
+    assert "networkx" in nx.pagerank.backends
+    assert "networkx" not in _stub_func.backends
+
+    if "nx_loopback" in nx.config.backends:
+        from networkx.classes.tests.dispatch_interface import LoopbackBackendInterface
+
+        def stub_func_implementation(G):
+            return True
+
+        LoopbackBackendInterface._stub_func = staticmethod(stub_func_implementation)
+        try:
+            assert _stub_func(nx.Graph()) is True
+        finally:
+            del LoopbackBackendInterface._stub_func
+
+    with pytest.raises(NotImplementedError):
+        _stub_func(nx.Graph())