collector.VERSION constant from pyproject.toml via importlib.metadata

So that there's a single source of truth again; prior to uv the setup.py
file was loading the version from the constant... now we're doing it the
other way around.

Author: pda

src/buildkite_test_collector/collector/constants.py

@@ -2,5 +2,16 @@
 
 """This module defines collector-level constants."""
 
-COLLECTOR_NAME='buildkite-test-collector'
-VERSION='1.0.4'
+DISTRIBUTION_NAME = 'buildkite-test-collector'
+COLLECTOR_NAME = f"python-{DISTRIBUTION_NAME}"
+
+try:
+    from importlib.metadata import version, PackageNotFoundError
+    try:
+        VERSION = version(DISTRIBUTION_NAME)
+    except PackageNotFoundError:
+        # Fallback for development environments where package isn't installed
+        VERSION = 'dev'
+except ImportError:
+    # Fallback for edge cases
+    VERSION = 'unknown'

src/buildkite_test_collector/collector/run_env.py

@@ -5,7 +5,7 @@
 from typing import Dict, Optional, Mapping
 from uuid import uuid4
 
-from .constants import COLLECTOR_NAME, VERSION # pylint: disable=W0611
+from .constants import COLLECTOR_NAME, VERSION
 
 # pylint: disable=too-few-public-methods
 class RunEnvBuilder:
@@ -140,7 +140,7 @@ def as_json(self) -> Dict[str, str]:
             "commit_sha": self.commit_sha,
             "message": self.message,
             "url": self.url,
-            "collector": f"python-{COLLECTOR_NAME}",
+            "collector": COLLECTOR_NAME,
             "version": VERSION,
             "language_version": f"{platform.python_version()}"
         }

tests/buildkite_test_collector/collector/test_run_env.py

@@ -3,7 +3,7 @@
 from uuid import uuid4, UUID
 
 from buildkite_test_collector.collector.constants import VERSION
-from buildkite_test_collector.collector.run_env import RunEnv, RunEnvBuilder
+from buildkite_test_collector.collector.run_env import RunEnvBuilder
 
 
 def test_detect_env_with_buildkite_api_env_vars_returns_the_correct_environment():