Improve handling of missing component (#317)

* Improve handling of missing component

* docstring

src/ansible_dev_tools/version_builder.py

@@ -26,7 +26,10 @@ def version_builder() -> str:
     """
     lines = []
     for pkg in sorted(PKGS):
-        version = importlib.metadata.version(pkg)
+        try:
+            version = importlib.metadata.version(pkg)
+        except importlib.metadata.PackageNotFoundError:
+            version = "not installed"
         lines.append(f"{pkg: <40} {version}")
 
     return "\n".join(lines)

tests/unit/__init__.py

@@ -0,0 +1 @@
+"""Unit tests for the project."""

tests/unit/test_version_builder.py

@@ -0,0 +1,22 @@
+"""Tests for the version builder."""
+
+import re
+
+import pytest
+
+from ansible_dev_tools.version_builder import PKGS, version_builder
+
+
+def test_version_builder_success() -> None:
+    """Test the version builder."""
+    versions = version_builder()
+    assert all(p in versions for p in PKGS)
+
+
+def test_version_builder_failure(monkeypatch: pytest.MonkeyPatch) -> None:
+    """Test the version builder."""
+    monkeypatch.setattr("ansible_dev_tools.version_builder.PKGS", ["__invalid__"])
+
+    versions = version_builder()
+
+    assert re.search(r"__invalid__\s+not installed", versions)