Add test for bash-completion on Debian / Ubuntu.

tests/pytests/pkg/integration/test_bash_completion.py

@@ -0,0 +1,19 @@
+import pathlib
+
+
+def test_bash_completion_installed(grains):
+    # This test specifically checks for a regression of #66560.
+    if grains.get("os_family") == "Debian":
+        completions_dir = pathlib.Path("/usr/share/bash-completion/completions")
+        for exec_name in ("salt", "salt-call", "salt-cp", "salt-key"):
+            # Bash-completion finds the completion when it is installed as
+            # <command>, <command>.bash, or _<command>, so we test all three
+            # variants before failing.
+            completion_file1 = completions_dir / exec_name
+            completion_file2 = completions_dir / f"{exec_name}.bash"
+            completion_file3 = completions_dir / f"_{exec_name}"
+            assert (
+                completion_file1.exists()
+                or completion_file2.exists()
+                or completion_file3.exists()
+            )