From ed4cfc2c727d6bcbca2ffb406d75026cb26845a9 Mon Sep 17 00:00:00 2001
From: Chris Barnes <chris.barnes@gerbi-gmb.de>
Date: Tue, 7 Jul 2026 10:49:51 +0100
Subject: [PATCH 1/2] Allow transform graph to get self-edge sequence

Resolves #77
---
 src/transformnd/graph.py | 18 ++++++++++++------
 tests/test_graph.py      |  6 ++++++
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/transformnd/graph.py b/src/transformnd/graph.py
index a18d051..6c6bff9 100644
--- a/src/transformnd/graph.py
+++ b/src/transformnd/graph.py
@@ -10,6 +10,8 @@
 
 import networkx as nx
 
+from transformnd.transforms.simple import Identity
+
 from .transforms.bijection import Bijection
 from .base import Transform, TransformSequence
 from .util import SpaceRef, ArrayT, same_or_none
@@ -216,13 +218,17 @@ def get_sequence(
         """
         path = nx.shortest_path(self.graph, source_space, target_space, weight)  # type:ignore
         transforms = []
-        wfn = normalise_edge_weight_fn(weight)
+        if len(path) == 1:
+            # source == target
+            transforms.append(Identity[ArrayT](self.space_ndims[source_space]))
+        else:
+            wfn = normalise_edge_weight_fn(weight)
 
-        for src, tgt in pairwise(path):
-            edges = self.graph[src][tgt]
-            transforms.append(
-                min(edges.values(), key=lambda d: wfn(src, tgt, d))[TRANSFORM_KEY]
-            )
+            for src, tgt in pairwise(path):
+                edges = self.graph[src][tgt]
+                transforms.append(
+                    min(edges.values(), key=lambda d: wfn(src, tgt, d))[TRANSFORM_KEY]
+                )
 
         seq = TransformSequence(
             transforms,
diff --git a/tests/test_graph.py b/tests/test_graph.py
index eeb9f71..485d65d 100644
--- a/tests/test_graph.py
+++ b/tests/test_graph.py
@@ -19,6 +19,12 @@ def test_add_transforms():
     t.add_transform(Translate([10, 20], spaces=Spaces("b", "c")))
 
 
+def test_noop_path():
+    t: TransformGraph = TransformGraph()
+    t.add_transform(Scale([2, 2], spaces=Spaces("a", "b")))
+    t.get_sequence("a", "a")
+
+
 def test_path():
     t1 = Scale([2, 3], spaces=Spaces("a", "b"))
     t2 = Translate([10, 20], spaces=Spaces("b", "c"))

From 73944441255131a4169c65ff784c5c8cf0f285a9 Mon Sep 17 00:00:00 2001
From: Chris Barnes <chris.barnes@gerbi-gmb.de>
Date: Tue, 7 Jul 2026 10:55:14 +0100
Subject: [PATCH 2/2] Test full/ not full

---
 tests/test_graph.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tests/test_graph.py b/tests/test_graph.py
index 485d65d..0fe890d 100644
--- a/tests/test_graph.py
+++ b/tests/test_graph.py
@@ -19,10 +19,12 @@ def test_add_transforms():
     t.add_transform(Translate([10, 20], spaces=Spaces("b", "c")))
 
 
-def test_noop_path():
+@pytest.mark.parametrize(("full",), [(True,), (False,)])
+def test_noop_path(coords5x3, full):
     t: TransformGraph = TransformGraph()
     t.add_transform(Scale([2, 2], spaces=Spaces("a", "b")))
-    t.get_sequence("a", "a")
+    s = t.get_sequence("a", "a", full=full)
+    assert s.apply(coords5x3) == pytest.approx(coords5x3)
 
 
 def test_path():