diff --git a/pyproject.toml b/pyproject.toml
index 4d8bdb3..720fb7a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -13,6 +13,9 @@ dependencies = [
     "PySide6>=6.7,<7",
 ]
 
+[project.scripts]
+bedit-graphviz = "bedit_util.graphviz:main"
+
 [project.optional-dependencies]
 dev = [
     "pytest>=8",
diff --git a/tests/manual_test.py b/tests/manual_test.py
new file mode 100644
index 0000000..df982fa
--- /dev/null
+++ b/tests/manual_test.py
@@ -0,0 +1,12 @@
+import sys
+from bedit_core.serialization import load, save
+from bedit_core.bondgraph import causality_inference
+
+def main(path: str):
+    doc = load(path)
+    for id, root in doc.root.items():
+        doc.root[id] = causality_inference(doc.root[id])
+    save(doc, path)
+
+if __name__ == "__main__":
+    main(sys.argv[1])
\ No newline at end of file
diff --git a/tests/unit/test_bondgraph_flatten.py b/tests/unit/test_bondgraph_flatten.py
new file mode 100644
index 0000000..4f56b0b
--- /dev/null
+++ b/tests/unit/test_bondgraph_flatten.py
@@ -0,0 +1,88 @@
+from __future__ import annotations
+
+import pytest
+
+from bedit_core.bondgraph import flatten_bondgraph
+from bedit_core.models import (
+    BondConnection,
+    BondPort,
+    Component,
+    ComponentID,
+    ConnectionID,
+    EquationImplementation,
+    Graph,
+    GraphImplementation,
+    Interface,
+    PortID,
+    SignalDirection,
+)
+
+
+def _leaf(name: str, port_id: PortID) -> Component:
+    return Component(
+        name=name,
+        interface=Interface(
+            {port_id: BondPort(name="p", direction=SignalDirection.INPUT)}
+        ),
+        parameters={},
+        implementation=EquationImplementation(),
+    )
+
+
+@pytest.mark.unit
+def test_flattens_bonds_across_a_component_boundary() -> None:
+    boundary_id = PortID("boundary")
+    inner_id = PortID("inner")
+    outer_id = PortID("outer")
+    inner = _leaf("Inner", inner_id)
+    subsystem = Component(
+        name="Subsystem",
+        interface=Interface(
+            {
+                boundary_id: BondPort(
+                    name="boundary",
+                    direction=SignalDirection.INPUT,
+                )
+            }
+        ),
+        parameters={},
+        implementation=GraphImplementation(
+            Graph(
+                components={ComponentID("inner"): inner},
+                connections={
+                    ConnectionID("inside"): BondConnection(
+                        boundary_id,
+                        inner_id,
+                    )
+                },
+            )
+        ),
+    )
+    outer = _leaf("Outer", outer_id)
+    root = Component(
+        name="Root",
+        interface=Interface(),
+        parameters={},
+        implementation=GraphImplementation(
+            Graph(
+                components={
+                    ComponentID("subsystem"): subsystem,
+                    ComponentID("outer"): outer,
+                },
+                connections={
+                    ConnectionID("outside"): BondConnection(
+                        outer_id,
+                        boundary_id,
+                    )
+                },
+            )
+        ),
+    )
+
+    network = flatten_bondgraph(root)
+    boundary = next(port for port in network.ports if port.port_id == boundary_id)
+
+    assert len(network.components) == 4
+    assert len(network.ports) == 3
+    assert len(network.bonds) == 2
+    assert len(network.bonds_for(boundary)) == 2
diff --git a/tests/unit/test_graphviz_util.py b/tests/unit/test_graphviz_util.py
new file mode 100644
index 0000000..5e3f11c
--- /dev/null
+++ b/tests/unit/test_graphviz_util.py
@@ -0,0 +1,14 @@
+from __future__ import annotations
+
+import pytest
+
+from bedit_core.models import Document
+from bedit_util.graphviz import document_to_dot
+
+
+@pytest.mark.unit
+def test_dot_contains_component_name_path(minimal_document: Document) -> None:
+    dot = document_to_dot(minimal_document, "Root")
+
+    assert 'label="Root"' in dot
+    assert 'xlabel="Root"' in dot
diff --git a/untitled.bedit.json b/untitled.bedit.json
index 331db9f..e8d9957 100644
--- a/untitled.bedit.json
+++ b/untitled.bedit.json
@@ -23,7 +23,10 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
                     "causality_preference": "preferred_effort_out"
@@ -33,7 +36,10 @@
                     "name": "state",
                     "direction": "output",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "value_type": "real",
                     "quantity": "",
@@ -54,8 +60,13 @@
               "implementation": {
                 "implementation_type": "equation",
                 "declarations": [],
-                "initial_equations": ["state = 0;"],
-                "equations": ["der(state) = p.f;", "p.e = state/c;"]
+                "initial_equations": [
+                  "state = 0;"
+                ],
+                "equations": [
+                  "der(state) = p.f;",
+                  "p.e = state/c;"
+                ]
               }
             },
             "9ee2f42b-5ed1-446d-8790-c2a1df6b61d3": {
@@ -67,10 +78,13 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": true,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
-                    "causality_preference": "indifferent"
+                    "causality_preference": "single_flow_in"
                   }
                 }
               },
@@ -100,7 +114,10 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
                     "causality_preference": "indifferent"
@@ -121,7 +138,9 @@
                 "implementation_type": "equation",
                 "declarations": [],
                 "initial_equations": [],
-                "equations": ["p.e = r*p.f;"]
+                "equations": [
+                  "p.e = r*p.f;"
+                ]
               }
             },
             "2804f2f1-6123-4a53-aff1-87a3a8202711": {
@@ -133,7 +152,10 @@
                     "name": "p",
                     "direction": "output",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
                     "causality_preference": "fixed_effort_out"
@@ -152,9 +174,14 @@
               },
               "implementation": {
                 "implementation_type": "equation",
-                "declarations": ["Real f;"],
+                "declarations": [
+                  "Real f;"
+                ],
                 "initial_equations": [],
-                "equations": ["p.e = e;", "f = p.f;"]
+                "equations": [
+                  "p.e = e;",
+                  "f = p.f;"
+                ]
               }
             },
             "9f392c28-6bef-4b10-9305-93e250747007": {
@@ -166,17 +193,22 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": true,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
-                    "causality_preference": "indifferent"
+                    "causality_preference": "single_effort_in"
                   }
                 }
               },
               "parameters": {},
               "implementation": {
                 "implementation_type": "equation",
-                "declarations": ["Real e;"],
+                "declarations": [
+                  "Real e;"
+                ],
                 "initial_equations": [],
                 "equations": [
                   "e = p[1].e;",
@@ -196,7 +228,10 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
                     "causality_preference": "indifferent"
@@ -217,7 +252,9 @@
                 "implementation_type": "equation",
                 "declarations": [],
                 "initial_equations": [],
-                "equations": ["p.e = r*p.f;"]
+                "equations": [
+                  "p.e = r*p.f;"
+                ]
               }
             },
             "033b930e-bf79-403a-8b0b-a159f3c81ce9": {
@@ -229,7 +266,10 @@
                     "name": "p",
                     "direction": "input",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "domain": "power",
                     "causality_preference": "preferred_flow_out"
@@ -239,7 +279,10 @@
                     "name": "state",
                     "direction": "output",
                     "multiplicity": false,
-                    "matrix_size": [1, 1],
+                    "matrix_size": [
+                      1,
+                      1
+                    ],
                     "description": "",
                     "value_type": "real",
                     "quantity": "",
@@ -260,8 +303,13 @@
               "implementation": {
                 "implementation_type": "equation",
                 "declarations": [],
-                "initial_equations": ["state = 0;"],
-                "equations": ["der(state) = p.e;", "p.f = state/i;"]
+                "initial_equations": [
+                  "state = 0;"
+                ],
+                "equations": [
+                  "der(state) = p.e;",
+                  "p.f = state/i;"
+                ]
               }
             }
           },
@@ -270,42 +318,42 @@
               "connection_type": "bond",
               "source": "5b6a8a0c-0875-402c-bd74-11d086aac372",
               "target": "4306701a-6b1b-4d19-b8ff-45dbfa04f2d3",
-              "causality": "flow_out",
+              "causality": "effort_out",
               "undesired": false
             },
             "66414b62-ca76-4be6-8da4-72551f8ffc0e": {
               "connection_type": "bond",
               "source": "497b1f74-1186-471f-976a-36b07a451caf",
               "target": "4a3f69f2-b305-4305-92e3-3998634ff226",
-              "causality": "effort_out",
+              "causality": "flow_out",
               "undesired": false
             },
             "8aaa96b3-45ed-4674-8f7a-06b28178a5c8": {
               "connection_type": "bond",
               "source": "4306701a-6b1b-4d19-b8ff-45dbfa04f2d3",
               "target": "c87881f1-23b4-4a69-b586-8e3c7bf6e21e",
-              "causality": "effort_out",
+              "causality": "flow_out",
               "undesired": false
             },
             "ff606583-d31f-4638-93f7-926163db2665": {
               "connection_type": "bond",
               "source": "4306701a-6b1b-4d19-b8ff-45dbfa04f2d3",
               "target": "0ac7d4ea-77f7-4c0d-8e37-406ef66e4740",
-              "causality": "flow_out",
+              "causality": "effort_out",
               "undesired": false
             },
             "1f52dc5a-1847-4982-aabc-2538cf99a86f": {
               "connection_type": "bond",
               "source": "497b1f74-1186-471f-976a-36b07a451caf",
               "target": "0b9036b1-e4e4-437e-8c35-f5bb391b6cbd",
-              "causality": "flow_out",
+              "causality": "effort_out",
               "undesired": false
             },
             "5af42b61-2317-48a8-b32b-0e2dfd88368e": {
               "connection_type": "bond",
               "source": "4306701a-6b1b-4d19-b8ff-45dbfa04f2d3",
               "target": "497b1f74-1186-471f-976a-36b07a451caf",
-              "causality": "effort_out",
+              "causality": "flow_out",
               "undesired": false
             }
           }