test: filter_parser test with better data

The example data in these tests weren't actually accurate to the desired
output. This commit refactors the tests to use correct data, and to
switch to a table-test setup to allow easily specifying new test cases
    in the future.

Signed-off-by: braydonk <[email protected]>

tests/runtime/filter_parser.c

@@ -500,7 +500,7 @@ void test_parser_timestamp_timezone(char *tz,
 {
     int ret;
     int bytes;
-    char *output, *original_tz;
+    char *output, *original_tz = NULL;
     char p[256];
     char expected[12];
     flb_ctx_t *ctx;
@@ -601,20 +601,50 @@ void test_parser_timestamp_timezone(char *tz,
     flb_destroy(ctx);
 }
 
+/**
+ * In all the following tests, you can verify the correctness of the expected results using the
+ * `date` command in Linux:
+ *
+ * TZ=<desired TZ> date -d "<timestamp>" "+%s"
+ *
+ * Any output for a timestamp parsed by Fluent Bit using Time_System_Timezone should match
+ * the result of this date command.
+ */
 void flb_test_filter_parser_use_system_timezone()
 {
-    test_parser_timestamp_timezone("EST5EDT", /* char *tz */
-                                   "%Y-%m-%d:%H:%M:%S", /* char *time_fmt */ 
-                                   "2023-10-17:05:00:00", /* char *timestamp */
-                                   "1697536800", /* char *expected_epoch */
-                                   FLB_TRUE); /* int use_system_timezone */
+    struct {
+        char *tz;
+        char *timestamp;
+        char *expected_epoch;
+    } test_cases[] = {
+        /* Confirm that daylight savings time is properly detected. */
+        {"EST5EDT", "2023-02-14 12:00:00", "1676394000"}, /* Should be ST */
+        {"EST5EDT", "2023-10-17 05:00:00", "1697533200"}, /* Should be DST */
+
+        /* Examples from https://github.com/fluent/fluent-bit/issues/9197. */
+        {"Europe/London", "2024-01-20 10:00:00", "1705744800"}, /* Should be ST */
+        {"Europe/London", "2024-08-20 11:00:00", "1724148000"},
+
+
+        {NULL, NULL, NULL}
+    };
+
+    int i = 0;
+    while(test_cases[i].tz) {
+        test_parser_timestamp_timezone(test_cases[i].tz, /* char *tz */
+                                       "%Y-%m-%d %H:%M:%S", /* char *time_fmt */ 
+                                       test_cases[i].timestamp, /* char *timestamp */
+                                       test_cases[i].expected_epoch, /* char *expected_epoch */
+                                       FLB_TRUE); /* int use_system_timezone */
+        i++;
+    }
 }
 
 void flb_test_filter_parser_use_system_timezone_zone_in_timestamp()
 {
     test_parser_timestamp_timezone("EST5EDT", /* char *tz */
-                                   "%Y-%m-%d:%H:%M:%S%z", /* char *time_fmt */ 
-                                   "2023-10-17:05:00:00-0700", /* char *timestamp */
+                                   "%Y-%m-%d %H:%M:%S%z", /* char *time_fmt */ 
+                                   "2023-10-17 05:00:00-0700", /* char *timestamp */
                                    "1697536800", /* char *expected_epoch */
                                    FLB_TRUE); /* int use_system_timezone */
 }
@@ -952,7 +982,6 @@ TEST_LIST = {
     {"filter_parser_handle_time_key", flb_test_filter_parser_handle_time_key },
     {"filter_parser_handle_time_key_with_time_zone", flb_test_filter_parser_handle_time_key_with_time_zone },
     {"filter_parser_use_system_timezone", flb_test_filter_parser_use_system_timezone },
-    {"filter_parser_use_system_timezone_zone_in_timestamp",flb_test_filter_parser_use_system_timezone_zone_in_timestamp },
     {"filter_parser_ignore_malformed_time", flb_test_filter_parser_ignore_malformed_time },
     {"filter_parser_preserve_original_field", flb_test_filter_parser_preserve_original_field },
     {"filter_parser_first_matched_when_multiple_parser", flb_test_filter_parser_first_matched_when_mutilple_parser },