import graphlib
import os
import unittest
from test.support.script_helper import assert_python_ok
class TestTopologicalSort(unittest.TestCase):
def _test_graph(self, graph, expected):
def static_order_with_groups(ts):
ts.prepare()
while ts.is_active():
nodes = ts.get_ready()
for node in nodes:
ts.done(node)
yield tuple(sorted(nodes))
ts = graphlib.TopologicalSorter(graph)
self.assertEqual(list(static_order_with_groups(ts)), list(expected))
ts = graphlib.TopologicalSorter(graph)
# need to be a bit careful comparing the result of ts.static_order and
# expected, because the order within a group is dependent on set
# iteration order
it = iter(ts.static_order())
for group in expected:
tsgroup = {next(it) for element in group}
self.assertEqual(set(group), tsgroup)
def _assert_cycle(self, graph, cycle):
ts = graphlib.TopologicalSorter()
for node, dependson in graph.items():
ts.add(node, *dependson)
try:
ts.prepare()
except graphlib.CycleError as e:
_, seq = e.args
self.assertIn(" ".join(map(str, cycle)), " ".join(map(str, seq * 2)))
else:
raise
def test_simple_cases(self):
self._test_graph(
{2: {11}, 9: {11, 8}, 10: {11, 3}, 11: {7, 5}, 8: {7, 3}},
[(3, 5, 7), (8, 11), (2, 9, 10)],
)
self._test_graph({1: {}}, [(1,)])
self._test_graph(
{x: {x + 1} for x in range(10)}, [(x,) for x in range(10, -1, -1)]
)
self._test_graph(
{2: {3}, 3: {4}, 4: {5}, 5: {1}, 11: {12}, 12: {13}, 13: {14}, 14: {15}},
[(1, 15), (5, 14), (4, 13), (3, 12), (2, 11)],
)
self._test_graph(
{
0: [1, 2],
1: [3],
2: [5, 6],
3: [4],
4: [9],
5: [3],
6: [7],
7: [8],
8: [4],
9: [],
},
[(9,), (4,), (3, 8), (1, 5, 7), (6,), (2,), (0,)],
)
self._test_graph({0: [1, 2], 1: [], 2: [3], 3: []}, [(1, 3), (2,), (0,)])
self._test_graph(
{0: [1, 2], 1: [], 2: [3], 3: [], 4: [5], 5: [6], 6: []},
[(1, 3, 6), (2, 5), (0, 4)],
)
def test_no_dependencies(self):
self._test_graph({1: {2}, 3: {4}, 5: {6}}, [(2, 4, 6), (1, 3, 5)])
self._test_graph({1: set(), 3: set(), 5: set()}, [(1, 3, 5)])
def test_the_node_multiple_times(self):
# Test same node multiple times in dependencies
self._test_graph({1: {2}, 3: {4}, 0: [2, 4, 4, 4, 4, 4]}, [(2, 4), (0, 1, 3)])
# Test adding the same dependency multiple times
ts = graphlib.TopologicalSorter()
ts.add(1, 2)
ts.add(1, 2)
ts.add(1, 2)
self.assertEqual([*ts.static_order()], [2, 1])
def test_graph_with_iterables(self):
dependson = (2 * x + 1 for x in range(5))
ts = graphlib.TopologicalSorter({0: dependson})
self.assertEqual(list(ts.static_order()), [1, 3, 5, 7, 9, 0])
def test_add_dependencies_for_same_node_incrementally(self):
# Test same node multiple times
ts = graphlib.TopologicalSorter()
ts.add(1, 2)
ts.add(1, 3)
ts.add(1, 4)
ts.add(1, 5)
ts2 = graphlib.TopologicalSorter({1: {2, 3, 4, 5}})
self.assertEqual([*ts.static_order()], [*ts2.static_order()])
def test_empty(self):
self._test_graph({}, [])
def test_cycle(self):
# Self cycle
self._assert_cycle({1: {1}}, [1, 1])
# Simple cycle
self._assert_cycle({1: {2}, 2: {1}}, [1, 2, 1])
# Indirect cycle
self._assert_cycle({1: {2}, 2: {3}, 3: {1}}, [1, 3, 2, 1])
# not all elements involved in a cycle
self._assert_cycle({1: {2}, 2: {3}, 3: {1}, 5: {4}, 4: {6}}, [1, 3, 2, 1])
# Multiple cycles
self._assert_cycle({1: {2}, 2: {1}, 3: {4}, 4: {5}, 6: {7}, 7: {6}}, [1, 2, 1])
# Cycle in the middle of the graph
self._assert_cycle({1: {2}, 2: {3}, 3: {2, 4}, 4: {5}}, [3, 2])
def test_calls_before_prepare(self):
ts = graphlib.TopologicalSorter()
with self.assertRaisesRegex(ValueError, r"prepare\(\) must be called first"):
ts.get_ready()
with self.assertRaisesRegex(ValueError, r"prepare\(\) must be called first"):
ts.done(3)
with self.assertRaisesRegex(ValueError, r"prepare\(\) must be called first"):
ts.is_active()
def test_prepare_multiple_times(self):
ts = graphlib.TopologicalSorter()
ts.prepare()
with self.assertRaisesRegex(ValueError, r"cannot prepare\(\) more than once"):
ts.prepare()
def test_invalid_nodes_in_done(self):
ts = graphlib.TopologicalSorter()
ts.add(1, 2, 3, 4)
ts.add(2, 3, 4)
ts.prepare()
ts.get_ready()
with self.assertRaisesRegex(ValueError, "node 2 was not passed out"):
ts.done(2)
with self.assertRaisesRegex(ValueError, r"node 24 was not added using add\(\)"):
ts.done(24)
def test_done(self):
ts = graphlib.TopologicalSorter()
ts.add(1, 2, 3, 4)
ts.add(2, 3)
ts.prepare()
self.assertEqual(ts.get_ready(), (3, 4))
# If we don't mark anything as done, get_ready() returns nothing
self.assertEqual(ts.get_ready(), ())
ts.done(3)
# Now 2 becomes available as 3 is done
self.assertEqual(ts.get_ready(), (2,))
self.assertEqual(ts.get_ready(), ())
ts.done(4)
ts.done(2)
# Only 1 is missing
self.assertEqual(ts.get_ready(), (1,))
self.assertEqual(ts.get_ready(), ())
ts.done(1)
self.assertEqual(ts.get_ready(), ())
self.assertFalse(ts.is_active())
def test_is_active(self):
ts = graphlib.TopologicalSorter()
ts.add(1, 2)
ts.prepare()
self.assertTrue(ts.is_active())
self.assertEqual(ts.get_ready(), (2,))
self.assertTrue(ts.is_active())
ts.done(2)
self.assertTrue(ts.is_active())
self.assertEqual(ts.get_ready(), (1,))
self.assertTrue(ts.is_active())
ts.done(1)
self.assertFalse(ts.is_active())
def test_not_hashable_nodes(self):
ts = graphlib.TopologicalSorter()
self.assertRaises(TypeError, ts.add, dict(), 1)
self.assertRaises(TypeError, ts.add, 1, dict())
self.assertRaises(TypeError, ts.add, dict(), dict())
def test_order_of_insertion_does_not_matter_between_groups(self):
def get_groups(ts):
ts.prepare()
while ts.is_active():
nodes = ts.get_ready()
ts.done(*nodes)
yield set(nodes)
ts = graphlib.TopologicalSorter()
ts.add(3, 2, 1)
ts.add(1, 0)
ts.add(4, 5)
ts.add(6, 7)
ts.add(4, 7)
ts2 = graphlib.TopologicalSorter()
ts2.add(1, 0)
ts2.add(3, 2, 1)
ts2.add(4, 7)
ts2.add(6, 7)
ts2.add(4, 5)
self.assertEqual(list(get_groups(ts)), list(get_groups(ts2)))
def test_static_order_does_not_change_with_the_hash_seed(self):
def check_order_with_hash_seed(seed):
code = """if 1:
import graphlib
ts = graphlib.TopologicalSorter()
ts.add('blech', 'bluch', 'hola')
ts.add('abcd', 'blech', 'bluch', 'a', 'b')
ts.add('a', 'a string', 'something', 'b')
ts.add('bluch', 'hola', 'abcde', 'a', 'b')
print(list(ts.static_order()))
"""
env = os.environ.copy()
# signal to assert_python not to do a copy
# of os.environ on its own
env["__cleanenv"] = True
env["PYTHONHASHSEED"] = str(seed)
out = assert_python_ok("-c", code, **env)
return out
run1 = check_order_with_hash_seed(1234)
run2 = check_order_with_hash_seed(31415)
self.assertNotEqual(run1, "")
self.assertNotEqual(run2, "")
self.assertEqual(run1, run2)
if __name__ == "__main__":
unittest.main()
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