Add symlink log smoke test and fix formatting in warning string

sky/utils/log_utils.py

@@ -210,7 +210,7 @@ def create_and_symlink_log_dir(log_dir: str):
             os.remove(symlink_path)
         else:
             logger.warning((
-                'Failed to create symlink to latest logs at \'{symlink_path}\'.'
+                f'Failed to create symlink to latest logs at \'{symlink_path}\'.'
                 'Please remove the existing file/directory.'))
             return
     os.symlink(log_dir, symlink_path)

tests/test_smoke.py

@@ -1317,6 +1317,24 @@ def test_scp_logs():
     run_one_test(test)
 
 
+@pytest.mark.kubernetes
+def test_symlink_latest_logs():
+    test = Test(
+        'symlink_latest_logs', 
+        [
+            'sky local up || true',
+            'eval symlink_path="~/sky_logs/sky_latest"; [ -L "$symlink_path" ] || exit 1 ;'
+            'target_file=$(readlink -f "$symlink_path") || exit 1 ;'
+            'sky local down || true ;'
+            '[ -L "$symlink_path" ] || exit 1 ;'
+            'target_file2=$(readlink -f "$symlink_path") ;'
+            '[ "$target_file" != "$target_file2" ] || exit 1'
+        ], 
+        'sky local down',
+    )
+    run_one_test(test)
+
+
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