def test_ControlFlowGraph_node_name_changes_hash():
"""Test that hash depends on node name."""
g1 = control_flow_graph.ControlFlowGraph()
g1.add_node(0, name="A", entry=True)
g2 = control_flow_graph.ControlFlowGraph()
g2.add_node(0, name="B", entry=True)
assert hash(g1) != hash(g2)
def test_ControlFlowGraph_IsomorphicHash_equivalency():
"""Test equivalent hashes, despite different attributes."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph(name="foo")
g1.add_node(0, name="A", entry=True)
g1.add_node(1, name="B", exit=True)
g1.add_edge(0, 1)
# Graph 2: C --> D
g2 = control_flow_graph.ControlFlowGraph(name="bar")
g2.add_node(0, name="C", entry=True)
g2.add_node(1, name="D", exit=True)
g2.add_edge(0, 1)
assert g1.IsomorphicHash() == g2.IsomorphicHash()
def test_ControlFlowGraph_unequal_graph_names_are_equal():
"""Test that graph names are not used in comparison."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph(name="foo")
g1.add_node(0, name="A", entry=True)
g1.add_node(1, name="B", exit=True)
g1.add_edge(0, 1)
# Graph 2: A --> B
g2 = control_flow_graph.ControlFlowGraph(name="bar")
g2.add_node(0, name="A", entry=True)
g2.add_node(1, name="B", exit=True)
g2.add_edge(0, 1)
assert g1 == g2
def test_ControlFlowGraph_unequal_edge_data():
"""Test that edge data is used in comparison."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph(name="foo")
g1.add_node(0, name="A", exit=True)
g1.add_node(1, name="B")
g1.add_edge(0, 1)
# Graph 2: A --> B
g2 = control_flow_graph.ControlFlowGraph(name="bar")
g2.add_node(0, name="A")
g2.add_node(1, name="B", entry=True)
g2.add_edge(0, 1)
assert g1 != g2
def test_ControlFlowGraph_equal():
"""Test that equal graphs can be compared."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph()
g1.add_node(0, name="A", entry=True)
g1.add_node(1, name="B", exit=True)
g1.add_edge(0, 1)
# Graph 2: A --> B
g2 = control_flow_graph.ControlFlowGraph()
g2.add_node(0, name="A", entry=True)
g2.add_node(1, name="B", exit=True)
g2.add_edge(0, 1)
assert g1 == g2
def test_ControlFlowGraph_equivalent_hashes():
"""Test equivalent hashes, despite different graph names."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph(name="foo")
g1.add_node(0, name="A", entry=True)
g1.add_node(1, name="B", exit=True)
g1.add_edge(0, 1)
# Graph 2: A --> B
g2 = control_flow_graph.ControlFlowGraph(name="bar")
g2.add_node(0, name="A", entry=True)
g2.add_node(1, name="B", exit=True)
g2.add_edge(0, 1)
assert hash(g1) == hash(g2)
def test_ControlFlowGraph_unequal_edges():
"""Test that graphs with unequal edges are not equal."""
# Graph 1: A --> B
g1 = control_flow_graph.ControlFlowGraph()
g1.add_node(0, name="A", entry=True)
g1.add_node(1, name="B", exit=True)
g1.add_edge(0, 1)
# Graph 2: B --> A
g2 = control_flow_graph.ControlFlowGraph()
g2.add_node(0, name="A", entry=True)
g2.add_node(1, name="B", exit=True)
g2.add_edge(1, 0)
assert g1 != g2
def test_ControlFlowGraph_edge_density():
"""Test edge density property."""
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> C -----+
g = control_flow_graph.ControlFlowGraph()
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
assert g.edge_density == pytest.approx(1 / 4)
# Add A -> D path.
g.add_edge(0, 3)
assert g.edge_density == pytest.approx(5 / 16)
def test_ControlFlowGraph_validate_empty_graph():
"""Test that empty graph is invalid."""
g = control_flow_graph.ControlFlowGraph()
with test.Raises(control_flow_graph.NotEnoughNodes) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "Function `cfg` has no nodes"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_irreducible_loop():
"""Test that an irreducible graph is valid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
# +-------+
# | |
# v |
# A------->B+----->C
# | | ^
# | | |
# | v |
# | D |
# | |
# +----------------+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 2)
g.add_edge(2, 1)
g.add_edge(1, 3)
assert g.ValidateControlFlowGraph() == g
assert g.IsValidControlFlowGraph()
def test_ControlFlowGraph_undirected_diameter():
"""Test undirected_diameter property."""
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> C -----+
g = control_flow_graph.ControlFlowGraph()
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
assert g.undirected_diameter == 2
# Increase the diameter by adding a new E node and D -> E path.
g.add_node(4, name="E")
g.add_edge(3, 4)
assert g.undirected_diameter == 3
def test_ControlFlowGraph_IsValidControlFlowGraph_exit_block_has_output():
"""Test that an if-else loop graph is valid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----> B -----+
# | |
# | v
# A<-----------+D
# | ^
# | |
# +----> C -----+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
g.add_edge(3, 0)
with test.Raises(control_flow_graph.InvalidNodeDegree) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "Exit block outdegree(D) = 1 in function `cfg`"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_node_attribute_changes_hash():
"""Test that hash depends on node attributes."""
g1 = control_flow_graph.ControlFlowGraph()
g1.add_node(0, name="A")
g2 = g1.copy()
assert hash(g1) == hash(g2)
g2.nodes[0]["entry"] = True
assert hash(g1) != hash(g2)
def test_ControlFlowGraph_IsValidControlFlowGraph_disconnected_graph():
"""A disconnected graph is not valid."""
g = control_flow_graph.ControlFlowGraph()
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B", exit=True)
g.add_node(2, name="C")
g.add_edge(0, 1)
with test.Raises(control_flow_graph.UnconnectedNode) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "Unconnected node 'C'"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_no_path_from_entry_to_exit():
"""A disconnected graph is not valid."""
# Graph: A -> B <- C
g = control_flow_graph.ControlFlowGraph()
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C", exit=True)
g.add_edge(0, 1)
g.add_edge(2, 1)
with test.Raises(
control_flow_graph.MalformedControlFlowGraphError) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == ("No path from entry node 'A' to exit node 'C' "
"in function `cfg`")
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_invalid_degrees():
"""Test that a graph where two nodes could be fused is invalid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# A --> B --> C
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C", exit=True)
g.add_edge(0, 1)
g.add_edge(1, 2)
with test.Raises(control_flow_graph.InvalidNodeDegree) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "outdegree(A) = 1, indegree(B) = 1"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_while_loop():
"""Test that a while loop graph is valid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +--------+
# | |
# v |
# A+------>B C
# | ^
# | |
# +----------------+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C", exit=True)
g.add_edge(0, 1)
g.add_edge(1, 0)
g.add_edge(0, 2)
assert g.ValidateControlFlowGraph() == g
assert g.IsValidControlFlowGraph()
def test_ControlFlowGraph_exit_block():
"""Test exit block."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> C -----+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
assert g.exit_blocks == [3]
def test_ControlFlowGraph_IsValidControlFlowGraph_if_else_loop():
"""Test that an if-else loop graph is valid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> C -----+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
assert g.ValidateControlFlowGraph() == g
assert g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_while_loop_with_exit():
"""Test that a while loop with an if branch exit is valid."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----------------+
# | |
# v |
# A+------>B+----->C D
# | | ^
# | | |
# +------->+---------------+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="C")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(1, 2)
g.add_edge(2, 0)
g.add_edge(0, 3)
g.add_edge(1, 3)
assert g.ValidateControlFlowGraph() == g
assert g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_unamed_nodes():
"""Test that all nodes in a graph must have a name."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> -----+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2)
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
with test.Raises(control_flow_graph.MissingNodeName) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "Node 2 has no name in function `cfg`"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_IsValidControlFlowGraph_duplicate_names():
"""Test that duplicate names is an error."""
g = control_flow_graph.ControlFlowGraph()
# Graph:
#
# +----> B -----+
# | |
# | v
# A D
# | ^
# | |
# +----> B -----+
g.add_node(0, name="A", entry=True)
g.add_node(1, name="B")
g.add_node(2, name="B")
g.add_node(3, name="D", exit=True)
g.add_edge(0, 1)
g.add_edge(0, 2)
g.add_edge(1, 3)
g.add_edge(2, 3)
with test.Raises(control_flow_graph.DuplicateNodeName) as e_ctx:
g.ValidateControlFlowGraph()
assert str(e_ctx.value) == "Duplicate node name 'B' in function `cfg`"
assert not g.IsValidControlFlowGraph()
def test_ControlFlowGraph_validate_one_node():
"""Test that single-node graph is valid."""
g = control_flow_graph.ControlFlowGraph()
g.add_node(0, name="A", entry=True, exit=True)
g.ValidateControlFlowGraph()
