[core][compiled graphs] Enable visualization tests (#48627)

In #47958 , visualization unit tests were introduced but would not run if CI environment does not have graphvis installed (which was the case).

This PR adds the dependency in test-requirements.txt and always run the visualization tests. It also moves visualization tests to a separate file since test_accelerated_dag.py is too large.

python/ray/dag/BUILD

@@ -108,6 +108,7 @@ py_test_module_list(
         "tests/experimental/test_torch_tensor_dag.py",
         "tests/experimental/test_collective_dag.py",
         "tests/experimental/test_execution_schedule.py",
+        "tests/experimental/test_dag_visualization.py",
     ],
     tags = [
         "accelerated_dag",

python/ray/dag/tests/experimental/test_accelerated_dag.py

@@ -30,10 +30,6 @@
 
 logger = logging.getLogger(__name__)
 
-try:
-    import pydot
-except Exception:
-    logging.info("pydot is not installed, visualization tests will be skiped")
 
 pytestmark = [
     pytest.mark.skipif(
@@ -2489,173 +2485,6 @@ async def main():
     loop.run_until_complete(main())
 
 
-class TestVisualization:
-
-    """Tests for the visualize method of compiled DAGs."""
-
-    # TODO(zhilong): "pip intsall pydot"
-    # and "sudo apt-get install graphviz " to run test.
-    @pytest.fixture(autouse=True)
-    def skip_if_pydot_graphviz_not_available(self):
-        # Skip the test if pydot or graphviz is not available
-        pytest.importorskip("pydot")
-        pytest.importorskip("graphviz")
-
-    def test_visualize_basic(self, ray_start_regular):
-        """
-        Expect output or dot_source:
-            MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
-                0 -> 1 [label=SharedMemoryType]
-                1 -> 2 [label=SharedMemoryType]
-        """
-
-        @ray.remote
-        class Actor:
-            def echo(self, x):
-                return x
-
-        actor = Actor.remote()
-
-        with InputNode() as i:
-            dag = actor.echo.bind(i)
-
-        compiled_dag = dag.experimental_compile()
-
-        # Call the visualize method
-        dot_source = compiled_dag.visualize(return_dot=True)
-
-        graphs = pydot.graph_from_dot_data(dot_source)
-        graph = graphs[0]
-
-        node_names = {node.get_name() for node in graph.get_nodes()}
-        edge_pairs = {
-            (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
-        }
-
-        expected_nodes = {"0", "1", "2"}
-        assert expected_nodes.issubset(
-            node_names
-        ), f"Expected nodes {expected_nodes} not found."
-
-        expected_edges = {("0", "1"), ("1", "2")}
-        assert expected_edges.issubset(
-            edge_pairs
-        ), f"Expected edges {expected_edges} not found."
-
-        compiled_dag.teardown()
-
-    def test_visualize_multi_return(self, ray_start_regular):
-        """
-        Expect output or dot_source:
-            MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
-                0 -> 1 [label=SharedMemoryType]
-                1 -> 2 [label=SharedMemoryType]
-                1 -> 3 [label=SharedMemoryType]
-                2 -> 4 [label=SharedMemoryType]
-                3 -> 4 [label=SharedMemoryType]
-        """
-
-        @ray.remote
-        class Actor:
-            @ray.method(num_returns=2)
-            def return_two(self, x):
-                return x, x + 1
-
-        actor = Actor.remote()
-
-        with InputNode() as i:
-            o1, o2 = actor.return_two.bind(i)
-            dag = MultiOutputNode([o1, o2])
-
-        compiled_dag = dag.experimental_compile()
-
-        # Get the DOT source
-        dot_source = compiled_dag.visualize(return_dot=True)
-
-        graphs = pydot.graph_from_dot_data(dot_source)
-        graph = graphs[0]
-
-        node_names = {node.get_name() for node in graph.get_nodes()}
-        edge_pairs = {
-            (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
-        }
-
-        expected_nodes = {"0", "1", "2", "3", "4"}
-        assert expected_nodes.issubset(
-            node_names
-        ), f"Expected nodes {expected_nodes} not found."
-
-        expected_edges = {("0", "1"), ("1", "2"), ("1", "3"), ("2", "4"), ("3", "4")}
-        assert expected_edges.issubset(
-            edge_pairs
-        ), f"Expected edges {expected_edges} not found."
-
-        compiled_dag.teardown()
-
-    def test_visualize_multi_return2(self, ray_start_regular):
-        """
-        Expect output or dot_source:
-            MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
-                0 -> 1 [label=SharedMemoryType]
-                1 -> 2 [label=SharedMemoryType]
-                1 -> 3 [label=SharedMemoryType]
-                2 -> 4 [label=SharedMemoryType]
-                3 -> 5 [label=SharedMemoryType]
-                4 -> 6 [label=SharedMemoryType]
-                5 -> 6 [label=SharedMemoryType]
-        """
-
-        @ray.remote
-        class Actor:
-            @ray.method(num_returns=2)
-            def return_two(self, x):
-                return x, x + 1
-
-            def echo(self, x):
-                return x
-
-        a = Actor.remote()
-        b = Actor.remote()
-        with InputNode() as i:
-            o1, o2 = a.return_two.bind(i)
-            o3 = b.echo.bind(o1)
-            o4 = b.echo.bind(o2)
-            dag = MultiOutputNode([o3, o4])
-
-        compiled_dag = dag.experimental_compile()
-
-        # Get the DOT source
-        dot_source = compiled_dag.visualize(return_dot=True)
-
-        graphs = pydot.graph_from_dot_data(dot_source)
-        graph = graphs[0]
-
-        node_names = {node.get_name() for node in graph.get_nodes()}
-        edge_pairs = {
-            (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
-        }
-
-        expected_nodes = {"0", "1", "2", "3", "4", "5", "6"}
-        assert expected_nodes.issubset(
-            node_names
-        ), f"Expected nodes {expected_nodes} not found."
-
-        expected_edges = {
-            ("0", "1"),
-            ("1", "2"),
-            ("1", "3"),
-            ("2", "4"),
-            ("3", "5"),
-            ("4", "6"),
-            ("5", "6"),
-        }
-        assert expected_edges.issubset(
-            edge_pairs
-        ), f"Expected edges {expected_edges} not found."
-
-        compiled_dag.teardown()
-
-
 if __name__ == "__main__":
     if os.environ.get("PARALLEL_CI"):
         sys.exit(pytest.main(["-n", "auto", "--boxed", "-vs", __file__]))

python/ray/dag/tests/experimental/test_dag_visualization.py

@@ -0,0 +1,172 @@
+import sys
+import ray
+import pydot
+import os
+from ray.dag import InputNode, MultiOutputNode
+from ray.tests.conftest import *  # noqa
+
+import pytest
+
+
+def test_visualize_basic(ray_start_regular):
+    """
+    Expect output or dot_source:
+        MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
+            0 -> 1 [label=SharedMemoryType]
+            1 -> 2 [label=SharedMemoryType]
+    """
+
+    @ray.remote
+    class Actor:
+        def echo(self, x):
+            return x
+
+    actor = Actor.remote()
+
+    with InputNode() as i:
+        dag = actor.echo.bind(i)
+
+    compiled_dag = dag.experimental_compile()
+
+    # Call the visualize method
+    dot_source = compiled_dag.visualize(return_dot=True)
+
+    graphs = pydot.graph_from_dot_data(dot_source)
+    graph = graphs[0]
+
+    node_names = {node.get_name() for node in graph.get_nodes()}
+    edge_pairs = {
+        (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
+    }
+
+    expected_nodes = {"0", "1", "2"}
+    assert expected_nodes.issubset(
+        node_names
+    ), f"Expected nodes {expected_nodes} not found."
+
+    expected_edges = {("0", "1"), ("1", "2")}
+    assert expected_edges.issubset(
+        edge_pairs
+    ), f"Expected edges {expected_edges} not found."
+
+    compiled_dag.teardown()
+
+
+def test_visualize_multi_return(ray_start_regular):
+    """
+    Expect output or dot_source:
+        MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
+            0 -> 1 [label=SharedMemoryType]
+            1 -> 2 [label=SharedMemoryType]
+            1 -> 3 [label=SharedMemoryType]
+            2 -> 4 [label=SharedMemoryType]
+            3 -> 4 [label=SharedMemoryType]
+    """
+
+    @ray.remote
+    class Actor:
+        @ray.method(num_returns=2)
+        def return_two(self, x):
+            return x, x + 1
+
+    actor = Actor.remote()
+
+    with InputNode() as i:
+        o1, o2 = actor.return_two.bind(i)
+        dag = MultiOutputNode([o1, o2])
+
+    compiled_dag = dag.experimental_compile()
+
+    # Get the DOT source
+    dot_source = compiled_dag.visualize(return_dot=True)
+
+    graphs = pydot.graph_from_dot_data(dot_source)
+    graph = graphs[0]
+
+    node_names = {node.get_name() for node in graph.get_nodes()}
+    edge_pairs = {
+        (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
+    }
+
+    expected_nodes = {"0", "1", "2", "3", "4"}
+    assert expected_nodes.issubset(
+        node_names
+    ), f"Expected nodes {expected_nodes} not found."
+
+    expected_edges = {("0", "1"), ("1", "2"), ("1", "3"), ("2", "4"), ("3", "4")}
+    assert expected_edges.issubset(
+        edge_pairs
+    ), f"Expected edges {expected_edges} not found."
+
+    compiled_dag.teardown()
+
+
+def test_visualize_multi_return2(ray_start_regular):
+    """
+    Expect output or dot_source:
+        MultiOutputNode" fillcolor=yellow shape=rectangle style=filled]
+            0 -> 1 [label=SharedMemoryType]
+            1 -> 2 [label=SharedMemoryType]
+            1 -> 3 [label=SharedMemoryType]
+            2 -> 4 [label=SharedMemoryType]
+            3 -> 5 [label=SharedMemoryType]
+            4 -> 6 [label=SharedMemoryType]
+            5 -> 6 [label=SharedMemoryType]
+    """
+
+    @ray.remote
+    class Actor:
+        @ray.method(num_returns=2)
+        def return_two(self, x):
+            return x, x + 1
+
+        def echo(self, x):
+            return x
+
+    a = Actor.remote()
+    b = Actor.remote()
+    with InputNode() as i:
+        o1, o2 = a.return_two.bind(i)
+        o3 = b.echo.bind(o1)
+        o4 = b.echo.bind(o2)
+        dag = MultiOutputNode([o3, o4])
+
+    compiled_dag = dag.experimental_compile()
+
+    # Get the DOT source
+    dot_source = compiled_dag.visualize(return_dot=True)
+
+    graphs = pydot.graph_from_dot_data(dot_source)
+    graph = graphs[0]
+
+    node_names = {node.get_name() for node in graph.get_nodes()}
+    edge_pairs = {
+        (edge.get_source(), edge.get_destination()) for edge in graph.get_edges()
+    }
+
+    expected_nodes = {"0", "1", "2", "3", "4", "5", "6"}
+    assert expected_nodes.issubset(
+        node_names
+    ), f"Expected nodes {expected_nodes} not found."
+
+    expected_edges = {
+        ("0", "1"),
+        ("1", "2"),
+        ("1", "3"),
+        ("2", "4"),
+        ("3", "5"),
+        ("4", "6"),
+        ("5", "6"),
+    }
+    assert expected_edges.issubset(
+        edge_pairs
+    ), f"Expected edges {expected_edges} not found."
+
+    compiled_dag.teardown()
+
+
+if __name__ == "__main__":
+    if os.environ.get("PARALLEL_CI"):
+        sys.exit(pytest.main(["-n", "auto", "--boxed", "-vs", __file__]))
+    else:
+        sys.exit(pytest.main(["-sv", __file__]))

python/requirements/test-requirements.txt

@@ -25,6 +25,7 @@ freezegun==1.1.0
 google-api-python-client==2.111.0
 google-cloud-storage==2.14.0
 gradio==3.50.2; platform_system != "Windows"
+graphviz==0.20.3
 websockets==11.0.3
 joblib==1.2.0
 jsonpatch==1.32