ci: run tests against Python 3.14

pyproject.toml

@@ -16,6 +16,7 @@ classifiers = [
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
   "Programming Language :: Python :: 3.13",
+  "Programming Language :: Python :: 3.14",
   "Topic :: Software Development",
 ]
 requires-python = ">=3.9"

taskcluster/kinds/docker-image/kind.yml

@@ -3,7 +3,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 ---
 meta:
-    - &uv_version 0.6.1
+    - &uv_version 0.9.3
 
 loader: taskgraph.loader.transform:loader
 
@@ -29,7 +29,7 @@ tasks:
     python:
         symbol: I(py)
         args:
-            PYTHON_VERSIONS: "3.13 3.12 3.11 3.10 3.9"
+            PYTHON_VERSIONS: "3.14 3.13 3.12 3.11 3.10 3.9"
             UV_VERSION: *uv_version
     run-task:
         symbol: I(rt)

taskcluster/kinds/test/kind.yml

@@ -42,7 +42,7 @@ tasks:
         matrix:
             set-name: "unit-py{matrix[python]}"
             substitution-fields: [description, run.command, treeherder, worker]
-            python: ["313", "312", "311", "310", "39"]
+            python: ["314", "313", "312", "311", "310", "39"]
         worker:
             artifacts:
                 - type: file

test/test_main.py

@@ -65,14 +65,23 @@ def test_show_taskgraph_attr(run_taskgraph, capsys, attr, expected):
 
 
 def test_show_taskgraph_parallel(run_taskgraph):
+    # Test that parallel execution works correctly with valid parameters
     res = run_taskgraph(["full", "-p", "taskcluster/test/params"])
     assert res == 0
 
-    # Craft params to cause an exception
-    res = run_taskgraph(
-        ["full", "-p", "taskcluster/test/params"], params={"_kinds": None}
-    )
-    assert res == 1
+
+def test_show_taskgraph_parallel_bad_params(tmp_path):
+    # Create parameter files that will cause processing errors
+    bad_params_dir = tmp_path / "bad_params"
+    bad_params_dir.mkdir()
+    (bad_params_dir / "invalid-yaml.yml").write_text("invalid: yaml: [syntax error")
+
+    try:
+        result = taskgraph_main(["full", "-p", str(bad_params_dir)])
+    except SystemExit as e:
+        result = e.code
+
+    assert result == 1
 
 
 def test_show_taskgraph_force_local_files_changed(mocker, run_taskgraph):