fix midnight bug issue

Author: JAi-SATHVIK

test/datetime/test_datetime.f90

@@ -1069,25 +1069,27 @@ end subroutine test_time_comparison_tz
 
 subroutine test_time_comparison_tz_midnight(error)
     !! Tests timezone comparison that crosses midnight:
-    !! 23:00 UTC-05:00 is the same instant as 04:00 UTC
+    !! 23:00 UTC-05:00 after modulo-24h normalisation maps to
+    !! 04:00 UTC, which should compare equal to time_type(4,0,0,0,0).
     type(error_type), allocatable, intent(out) :: error
     type(time_type) :: t1, t2
-    ! 23:00 UTC-05:00 (UTC ms = 23*3600000 + 5*3600000 = 100800000)
-    ! 04:00 UTC       (UTC ms = 4*3600000 = 14400000)
-    ! These are not equal as clock-face times on the same day;
-    ! the comparison is purely by UTC ms since midnight.
-    ! 23:00-05:00 UTC ms = 28*3600000 = 100800000 (> 24h, no wrap in comparison)
-    ! 04:00Z      UTC ms =  4*3600000 = 14400000
-    ! They should NOT be equal (different absolute UTC ms values).
+    ! time_eq uses time_to_normalized_utc_ms (modulo 86400000 ms).
+    ! 23:00 UTC-05:00 raw UTC ms = 100800000
+    !   modulo(100800000, 86400000) = 14400000  (04:00 UTC)
+    ! 04:00Z         raw UTC ms = 14400000
+    !   modulo(14400000, 86400000)  = 14400000
+    ! --> they ARE equal after midnight-wrap normalization.
     t1 = time_type(23, 0, 0, 0, -300)   ! 23:00 UTC-05:00
     t2 = time_type(4,  0, 0, 0,  0)     ! 04:00 UTC
+    call check(error, t1 == t2, &
+        "23:00-05:00 should equal 04:00Z after midnight-wrap")
+    if (allocated(error)) return
+    ! Verify a genuinely different time is NOT equal
+    t2 = time_type(5, 0, 0, 0, 0)       ! 05:00 UTC
     call check(error, .not. (t1 == t2), &
-        "23:00-05:00 and 04:00Z differ in UTC ms (no date wrap)")
+        "23:00-05:00 should NOT equal 05:00Z")
     if (allocated(error)) return
-    ! However, to_utc(t1) should give 04:00 after midnight-wrap
-    ! (tested separately in test_to_utc_time_midnight).
-    !
-    ! Sanity: 06:00-02:00 == 08:00Z (same-day, no crossing)
+    ! Same-day sanity: 06:00-02:00 == 08:00Z
     t1 = time_type(6, 0, 0, 0, -120)    ! 06:00 UTC-02:00
     t2 = time_type(8, 0, 0, 0,  0)      ! 08:00 UTC
     call check(error, t1 == t2, &