Add Python 3.14 testing to justfile

Author: seddonym

CONTRIBUTING.rst

@@ -99,7 +99,7 @@ Typical workflow (changes that involve Rust):
 1. Make a change to Rust code.
 2. Run ``just compile-and-test``. This will compile the Rust code, then run Rust and Python tests in the default version.
 
-There are also version-specific test commands (e.g. ``just test-3-13``) - run ``just help`` to see which ones.
+There are also version-specific test commands (e.g. ``just test-3-14``) - run ``just help`` to see which ones.
 
 Working with documentation
 --------------------------

justfile

@@ -32,7 +32,7 @@ test-python:
 
 # Runs tests under all supported Python versions, plus Rust.
 [group('testing')]
-test-all: test-python-3-9 test-python-3-10 test-python-3-11 test-python-3-12 test-python-3-13 test-rust
+test-all: test-python-3-9 test-python-3-10 test-python-3-11 test-python-3-12 test-python-3-13 test-python-3-14 test-rust
 
 # Runs tests under Python 3.9.
 [group('testing')]
@@ -59,6 +59,11 @@ test-python-3-12:
 test-python-3-13:
     UV_PYTHON=3.13 just test-python
 
+# Runs tests under Python 3.14.
+[group('testing')]
+test-python-3-14:
+    UV_PYTHON=3.14 just test-python
+
 # Format the Rust code.
 [group('formatting')]
 [working-directory: 'rust']