Merge pull request #10788 from ppentchev/pp-285-python

Add Peter Pentchev's Python solution to 285.

1 files changed, 73 insertions, 0 deletions

diff --git a/challenge-285/ppentchev/python/tests/unit/test_routes.py b/challenge-285/ppentchev/python/tests/unit/test_routes.py
new file mode 100644
index 0000000000..743e0d20d2
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+++ b/challenge-285/ppentchev/python/tests/unit/test_routes.py
@@ -0,0 +1,73 @@
+# SPDX-FileCopyrightText: Peter Pentchev <roam@ringlet.net>
+# SPDX-License-Identifier: BSD-2-Clause
+"""Test the first task in Perl weekly challenge 285, "No Connection"."""
+
+from __future__ import annotations
+
+import dataclasses
+
+import pytest
+
+from perl_weekly_285 import defs
+from perl_weekly_285 import routes
+
+
+@dataclasses.dataclass(frozen=True)
+class RoutesCase:
+    """A test case for the "No Connection" task."""
+
+    routes: list[tuple[str, str]]
+    """The routes to examine."""
+
+    expected: str
+    """The leaf destination we expect to find."""
+
+
+@pytest.mark.parametrize(
+    "tcase",
+    [
+        RoutesCase(
+            routes=[
+                ("me", "you"),
+            ],
+            expected="you",
+        ),
+        RoutesCase(
+            routes=[
+                ("here", "there"),
+                ("here", "everywhere"),
+                ("there", "everywhere"),
+            ],
+            expected="everywhere",
+        ),
+        RoutesCase(
+            routes=[("B", "C"), ("D", "B"), ("C", "A")],
+            expected="A",
+        ),
+    ],
+)
+def test_connection(*, tcase: RoutesCase) -> None:
+    """Make sure we can find the leaf destination."""
+    assert routes.solve_no_connection(tcase.routes) == tcase.expected
+
+
+@pytest.mark.parametrize(
+    "tcase",
+    [
+        RoutesCase(
+            routes=[
+                ("here", "there"),
+                ("here", "everywhere"),
+            ],
+            expected="not really",
+        ),
+        RoutesCase(
+            routes=[("me", "you"), ("you", "me")],
+            expected="not really",
+        ),
+    ],
+)
+def test_no_connection(*, tcase: RoutesCase) -> None:
+    """Make sure we cannot find any leaf destination."""
+    with pytest.raises(defs.NoSolutionError):
+        routes.solve_no_connection(tcase.routes)