[time] Use set_interval for CronTrigger instead of loop() (#15433)

esphome/components/time/automation.cpp

@@ -20,7 +20,12 @@ bool CronTrigger::matches(const ESPTime &time) {
   return time.is_valid() && this->seconds_[time.second] && this->minutes_[time.minute] && this->hours_[time.hour] &&
          this->days_of_month_[time.day_of_month] && this->months_[time.month] && this->days_of_week_[time.day_of_week];
 }
-void CronTrigger::loop() {
+void CronTrigger::setup() {
+  // Cron resolution is 1 second — check once per second instead of every loop iteration
+  this->set_interval(1000, [this]() { this->check_time_(); });
+}
+
+void CronTrigger::check_time_() {
   ESPTime time = this->rtc_->now();
   if (!time.is_valid())
     return;

esphome/components/time/automation.h

@@ -26,10 +26,11 @@ class CronTrigger : public Trigger<>, public Component {
   void add_day_of_week(uint8_t day_of_week);
   void add_days_of_week(const std::vector<uint8_t> &days_of_week);
   bool matches(const ESPTime &time);
-  void loop() override;
+  void setup() override;
   float get_setup_priority() const override;
 
  protected:
+  void check_time_();
   std::bitset<61> seconds_;
   std::bitset<60> minutes_;
   std::bitset<24> hours_;

tests/components/time/common.yaml

@@ -6,5 +6,9 @@ api:
 
 time:
   - platform: homeassistant
+    on_time:
+      - seconds: "0,10,20,30,40,50"
+        then:
+          - logger.log: "CronTrigger fired (every 10 seconds)"
   - platform: sntp
     id: sntp_time