Avoid renaming timestamp in TS functions

Author: ivancea

x-pack/plugin/esql/qa/testFixtures/src/main/resources/tbucket.csv-spec

@@ -348,22 +348,34 @@ day_total:long | hour_med:double | h:datetime               | message:keyword
 ;
 
 
-tbucketWithTimezone
+tbucketWithTimezoneAndDuration
+required_capability: ts_command_v0
 required_capability: date_trunc_timezone_support
 
 SET time_zone = "+05:00"\;
-FROM employees
-| RENAME hire_date as @timestamp
-| WHERE @timestamp >= "1980-01-01T00:00:00Z"
-| STATS by @timestamp, bucketHours = TBUCKET(3 hours), bucketDay = TBUCKET(1 day)
+TS k8s
+| WHERE @timestamp == "2024-05-10T00:04:49.000Z"
+| STATS by @timestamp, bucket = TBUCKET(3 hours)
 | SORT @timestamp
-| LIMIT 5
+| LIMIT 2
 ;
 
-@timestamp:date          | bucketHours:date          | bucketDay:date
-1985-02-18T00:00:00.000Z | 1985-02-17T22:00:00.000Z | 1985-02-17T19:00:00.000Z
-1985-02-24T00:00:00.000Z | 1985-02-23T22:00:00.000Z | 1985-02-23T19:00:00.000Z
-1985-05-13T00:00:00.000Z | 1985-05-12T22:00:00.000Z | 1985-05-12T19:00:00.000Z
-1985-07-09T00:00:00.000Z | 1985-07-08T22:00:00.000Z | 1985-07-08T19:00:00.000Z
-1985-09-17T00:00:00.000Z | 1985-09-16T22:00:00.000Z | 1985-09-16T19:00:00.000Z
+@timestamp:datetime      | bucket:datetime
+2024-05-10T00:04:49.000Z | 2024-05-09T22:00:00.000Z
+;
+
+tbucketWithTimezoneAndPeriod
+required_capability: ts_command_v0
+required_capability: date_trunc_timezone_support
+
+SET time_zone = "+05:00"\;
+TS k8s
+| WHERE @timestamp == "2024-05-10T00:04:49.000Z"
+| STATS by @timestamp, bucket = TBUCKET(1 day)
+| SORT @timestamp
+| LIMIT 2
+;
+
+@timestamp:datetime      | bucket:datetime
+2024-05-10T00:04:49.000Z | 2024-05-09T19:00:00.000Z
 ;

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/scalar/date/DateTruncTests.java

@@ -115,6 +115,8 @@ public static List<DurationTestCaseData> makeTruncDurationTestCases() {
             new DurationTestCaseData(Duration.ofHours(3), "2020-01-01T05:30:00Z", "UTC", "2020-01-01T03:00:00Z"),
             new DurationTestCaseData(Duration.ofHours(3), "2020-01-01T05:30:00Z", "+01:00", "2020-01-01T05:00:00Z"),
             new DurationTestCaseData(Duration.ofMinutes(3 * 60), "2020-01-01T05:30:00Z", "+01:00", "2020-01-01T05:00:00Z"),
+            new DurationTestCaseData(Duration.ofHours(6), "2024-03-01T00:30:00Z", "-03", "2024-02-29T21:00:00Z"),
+            new DurationTestCaseData(Duration.ofHours(24), "2024-03-01T00:30:00Z", "-03", "2024-02-29T03:00:00Z"),
             new DurationTestCaseData(Duration.ofHours(5), "2020-01-01T05:30:00Z", "+01", "2020-01-01T01:00:00Z"),
 
             ///
@@ -165,6 +167,11 @@ public static List<PeriodTestCaseData> makeTruncPeriodTestCases() {
             new PeriodTestCaseData(Period.ofMonths(7), ts, "UTC", "2022-11-01T00:00:00.00Z"),
             new PeriodTestCaseData(Period.ofYears(5), ts, "UTC", "2021-01-01T00:00:00.00Z"),
 
+            ///
+            /// Timezones
+            ///
+            new PeriodTestCaseData(Period.ofDays(1), "2024-03-01T00:30:00Z", "-03", "2024-02-29T03:00:00Z"),
+
             ///
             /// Timezone with DST (-5 to -4 at 2025-03-09T02:00:00-05, and -4 to -5 at 2025-11-02T02:00:00-04)
             ///