DEPS/TST: tzdata is optional, not required

pandas/conftest.py

@@ -79,6 +79,14 @@
     # Import "zoneinfo" could not be resolved (reportMissingImports)
     import zoneinfo  # type: ignore[no-redef]
 
+    # Although zoneinfo can be imported in Py39, it is effectively
+    # "not available" without tzdata/IANA tz data.
+    # We will set zoneinfo to not found in this case
+    try:
+        utc_zoneinfo = zoneinfo.ZoneInfo("UTC")
+    except zoneinfo.ZoneInfoNotFoundError:
+        zoneinfo = None
+
 # Until https://github.com/numpy/numpy/issues/19078 is sorted out, just suppress
 suppress_npdev_promotion_warning = pytest.mark.filterwarnings(
     "ignore:Promotion of numbers and bools:FutureWarning"