should be it

external/duckdb/test/sql/timezone/disable_timestamptz_casts.test

@@ -0,0 +1,60 @@
+# name: test/sql/timezone/disable_timestamptz_casts.test
+# description: Test for disabling timestamp => timestamptz casts
+# group: [timezone]
+
+# Setting has no effect when ICU is not loaded as the two types are equivalent
+statement ok
+set disable_timestamptz_casts=false;
+
+query I
+select cast('2020-01-01T00:00:00'::timestamp as timestamptz)
+----
+2020-01-01 00:00:00+00
+
+query I
+select cast('2020-01-01T15:00:00+0000'::timestamptz as timestamp)
+----
+2020-01-01 15:00:00
+
+statement ok
+set disable_timestamptz_casts=true;
+
+query I
+select cast('2020-01-01T00:00:00'::timestamp as timestamptz)
+----
+2020-01-01 00:00:00+00
+
+query I
+select cast('2020-01-01T15:00:00+0000'::timestamptz as timestamp)
+----
+2020-01-01 15:00:00
+
+# With ICU loaded, the casts are disabled in both directions when the flag is set.
+require icu
+
+statement ok
+set calendar='gregorian';
+
+statement ok
+set TimeZone='America/Los_Angeles';
+
+statement ok
+set disable_timestamptz_casts=false;
+
+query I
+select cast('2020-01-01T00:00:00'::timestamp as timestamptz)
+----
+2020-01-01 00:00:00-08
+
+statement ok
+set disable_timestamptz_casts=true;
+
+statement error
+select cast('2020-01-01T00:00:00'::timestamp as timestamptz)
+----
+Casting from TIMESTAMP to TIMESTAMP WITH TIME ZONE without an explicit time zone has been disabled
+
+statement error
+select cast('2020-01-01T15:00:00+0000'::timestamptz as timestamp)
+----
+Casting from TIMESTAMP WITH TIME ZONE to TIMESTAMP without an explicit time zone has been disabled

external/duckdb/test/sql/timezone/icu_calendar_operations.test

@@ -0,0 +1,40 @@
+# name: test/sql/timezone/icu_calendar_operations.test
+# description: Test the ICU calendar interface
+# group: [timezone]
+
+require icu
+
+# Normalise the testing locale
+statement ok
+SET TimeZone = 'UTC';
+
+# Test intervals for lunar calendars
+foreach cal hebrew coptic ethiopic
+
+statement ok
+SET Calendar = '${cal}';
+
+statement error
+select age('2020-01-01'::timestamptz);
+----
+INTERVALs do not work with 13 month calendars. Try using DATE_DIFF instead.
+
+statement error
+select '2020-01-01'::timestamptz + interval '380 days'
+----
+INTERVALs do not work with 13 month calendars. Try using DATE_DIFF instead.
+
+statement error
+select '2021-01-01'::timestamptz - interval '380 days'
+----
+INTERVALs do not work with 13 month calendars. Try using DATE_DIFF instead.
+
+statement error
+select 
+	'2020-01-01'::timestamptz as start_date,
+	'2021-01-01'::timestamptz as end_date,
+	age(end_date, start_date) as delta;
+----
+INTERVALs do not work with 13 month calendars. Try using DATE_DIFF instead.
+
+endloop

external/duckdb/test/sql/timezone/test_icu_calendar.test

@@ -0,0 +1,123 @@
+# name: test/sql/timezone/test_icu_calendar.test
+# description: Test the ICU calendar interface
+# group: [timezone]
+
+require icu
+
+# Normalise the testing locale
+statement ok
+SET Calendar = 'gregorian';
+
+statement ok
+SET TimeZone = 'America/Los_Angeles';
+
+query I
+SELECT name FROM icu_calendar_names()
+GROUP BY 1
+ORDER BY 1;
+----
+buddhist
+chinese
+coptic
+dangi
+ethiopic
+ethiopic-amete-alem
+gregorian
+hebrew
+indian
+islamic
+islamic-civil
+islamic-rgsa
+islamic-tbla
+islamic-umalqura
+iso8601
+japanese
+persian
+roc
+
+query IIIII
+SELECT name, value, description, input_type, scope FROM duckdb_settings() WHERE name = 'Calendar';
+----
+Calendar	gregorian	The current calendar	VARCHAR	LOCAL
+
+statement error
+SET Calendar = 'fnord';
+----
+
+#
+# Japanese calendar testing
+#
+
+# Create the table before changing calendars
+# Otherwise the parser will assume they are Japanese dates
+statement ok
+SET TimeZone = 'Asia/Tokyo';
+
+statement ok
+CREATE TABLE timestamps AS SELECT ts::TIMESTAMPTZ AS ts, era FROM (VALUES
+	('0645-06-30 00:00:00+00', 'Taika'),
+	('1867-01-01 00:00:00+00', 'Keiou'),
+	('1868-09-07 00:00:00+00', 'Keiou'),
+	('1868-09-08 00:00:00+00', 'Meiji'),
+	('1912-07-29 00:00:00+00', 'Meiji'),
+	('1912-07-30 00:00:00+00', 'Taisho'),
+	('1926-12-24 00:00:00+00', 'Taisho'),
+	('1926-12-25 00:00:00+00', 'Showa'),
+	('1989-01-06 00:00:00+00', 'Showa'),
+	('1989-01-08 00:00:00+00', 'Heisei'),
+	('2019-05-01 00:00:00+00', 'Reiwa'),
+	('2022-01-01 00:00:00+00', 'Reiwa')
+) tbl(ts, era);
+
+statement ok
+SET Calendar = 'japanese';
+
+query IIIII
+SELECT name, value, description, input_type, scope FROM duckdb_settings() WHERE name = 'Calendar';
+----
+Calendar	japanese	The current calendar	VARCHAR	LOCAL
+
+# See http://www.meijigakuin.ac.jp/~watson/ref/mtsh.html for details on recent era boundaries.
+query III
+SELECT era, ts, DATE_PART(['era', 'year', 'month', 'day'], ts)
+FROM timestamps
+ORDER BY 2
+----
+Taika	0645-06-27 09:18:59+09:18	{'era': 0, 'year': 1, 'month': 6, 'day': 27}
+Keiou	1867-01-01 09:18:59+09:18	{'era': 231, 'year': 3, 'month': 1, 'day': 1}
+Keiou	1868-09-07 09:18:59+09:18	{'era': 231, 'year': 4, 'month': 9, 'day': 7}
+Meiji	1868-09-08 09:18:59+09:18	{'era': 232, 'year': 1, 'month': 9, 'day': 8}
+Meiji	1912-07-29 09:00:00+09	{'era': 232, 'year': 45, 'month': 7, 'day': 29}
+Taisho	1912-07-30 09:00:00+09	{'era': 233, 'year': 1, 'month': 7, 'day': 30}
+Taisho	1926-12-24 09:00:00+09	{'era': 233, 'year': 15, 'month': 12, 'day': 24}
+Showa	1926-12-25 09:00:00+09	{'era': 234, 'year': 1, 'month': 12, 'day': 25}
+Showa	1989-01-06 09:00:00+09	{'era': 234, 'year': 64, 'month': 1, 'day': 6}
+Heisei	1989-01-08 09:00:00+09	{'era': 235, 'year': 1, 'month': 1, 'day': 8}
+Reiwa	2019-05-01 09:00:00+09	{'era': 236, 'year': 1, 'month': 5, 'day': 1}
+Reiwa	2022-01-01 09:00:00+09	{'era': 236, 'year': 4, 'month': 1, 'day': 1}
+
+# Issue #5234
+statement ok
+SET CALENDAR='islamic-umalqura';
+
+statement ok
+SELECT strftime(TIMESTAMPTZ '-260722-3-4 0:3:52',TIMESTAMP '-285441-5-3 8:3:4'::VARCHAR);
+
+# Issue #5235
+statement ok
+SET CALENDAR='indian';
+
+query I
+SELECT TIMESTAMPTZ '-276069-9-30 0:0:00 America/Whitehorse';
+----
+276070-10-01 (BC) 18:19:11+09:18
+
+# Issue #5237
+statement ok
+PRAGMA CALENDAR='japanese';
+
+# The TIMETZ cast is not valid (checked against PG)
+statement error
+SELECT strftime(TIMESTAMPTZ '-23831-1-15 2:5:17 America/La_Paz',TIMETZ '0:8:29 America/Cayman'::VARCHAR);
+----
+time field value out of range