From 12644bb362eceb2122332a166c84e3577ca19863 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Wed, 7 Oct 2026 03:54:04 +0000
Subject: [PATCH] =?UTF-8?q?=F0=9F=A7=AA=20Add=20missing=20error=20path=20t?=
 =?UTF-8?q?est=20for=20`resolve=5Fbind=5Ftarget`=20with=20unroutable=20IP?=
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Adds a test to cover the branch in `resolve_bind_target` where an explicit error is returned if `iface_for_ip` returns `None` for a valid IP. This covers an otherwise untested error path, bringing branch coverage to 100% for this code block.

Co-authored-by: Horizontal42 <75383519+Horizontal42@users.noreply.github.com>
---
 tests/test_iface.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/test_iface.py b/tests/test_iface.py
index d3dbf57..22f1fe1 100644
--- a/tests/test_iface.py
+++ b/tests/test_iface.py
@@ -61,6 +61,16 @@ def test_resolve_bind_target_by_exact_name():
     assert result.error is None
 
 
+def test_resolve_bind_target_by_unmapped_ip_is_an_error():
+    result = resolve_bind_target(
+        "10.255.255.255",
+        addrs(Ethernet=[(socket.AF_INET, "192.168.3.72")]),
+        up(Ethernet=True),
+    )
+    assert result.error is not None
+    assert result.error == "no adapter has the address '10.255.255.255'"
+
+
 def test_resolve_bind_target_by_ip_finds_owning_adapter():
     result = resolve_bind_target(
         "192.168.3.72",