Use correct end date for test run depending on org set timezone.

api/handle_scenario_test_run.go

@@ -23,8 +23,15 @@ func handleCreateScenarioTestRun(uc usecases.Usecases) func(c *gin.Context) {
 			c.Status(http.StatusBadRequest)
 			return
 		}
+
+		orgUsecase := usecasesWithCreds(ctx, uc).NewOrganizationUseCase()
+		org, err := orgUsecase.GetOrganization(c.Request.Context(), organizationId)
+		if presentError(ctx, c, err) {
+			return
+		}
+
 		usecase := usecasesWithCreds(ctx, uc).NewScenarioTestRunUseCase()
-		input, err := dto.AdaptCreateScenarioTestRunBody(data)
+		input, err := dto.AdaptCreateScenarioTestRunBody(data, org.DefaultScenarioTimezone)
 		if presentError(ctx, c, err) {
 			return
 		}

dto/scenario_testrun.go

@@ -37,7 +37,22 @@ type CreateScenarioTestRunBody struct {
 	EndDate         time.Time `json:"end_date"`
 }
 
-func AdaptCreateScenarioTestRunBody(dto CreateScenarioTestRunBody) (models.ScenarioTestRunInput, error) {
+func AdaptCreateScenarioTestRunBody(dto CreateScenarioTestRunBody, tzName *string) (models.ScenarioTestRunInput, error) {
+	tz := time.UTC
+
+	if tzName != nil {
+		orgTz, err := time.LoadLocation(*tzName)
+		if err == nil {
+			tz = orgTz
+		}
+	}
+
+	// Frontend always sends UTC timestamps granular to the day, which means it will be "the day before at 11pm".
+	// We add enough hours to be in the right day (passing any potential DST changes), then build a new end date
+	// in the organization timezone to represent the end of the selected day.
+	dto.EndDate = dto.EndDate.Add(5 * time.Hour)
+	dto.EndDate = time.Date(dto.EndDate.Year(), dto.EndDate.Month(), dto.EndDate.Day(), 23, 59, 59, 999999999, tz)
+
 	return models.ScenarioTestRunInput{
 		ScenarioId:         dto.ScenarioId,
 		EndDate:            dto.EndDate,