feat: Support HA event entities as triggers (#2506)

tests/ha/get-trigger-event-type.test.ts

@@ -0,0 +1,91 @@
+import { describe, expect, it } from 'vitest';
+import { getTriggerEventType } from '../../src/ha/get-trigger-event-type';
+import { createStateEntity } from '../test-utils';
+
+describe('getTriggerEventType', () => {
+  describe('for non-event entities', () => {
+    it.each([['on'], ['open'], ['unlocked']])(
+      'returns "new" when the new state is %s',
+      (state: string) => {
+        expect(
+          getTriggerEventType({
+            entityID: 'binary_sensor.motion',
+            oldState: createStateEntity({ state: 'off' }),
+            newState: createStateEntity({ state }),
+          }),
+        ).toBe('new');
+      },
+    );
+
+    it.each([
+      ['off'],
+      ['closed'],
+      ['locked'],
+      ['unavailable'],
+      ['unknown'],
+      ['anything-else'],
+    ])('returns "end" when the new state is %s', (state: string) => {
+      expect(
+        getTriggerEventType({
+          entityID: 'binary_sensor.motion',
+          oldState: createStateEntity({ state: 'on' }),
+          newState: createStateEntity({ state }),
+        }),
+      ).toBe('end');
+    });
+  });
+
+  describe('for event entities', () => {
+    it('returns "signal" for a transition between two real timestamps', () => {
+      expect(
+        getTriggerEventType({
+          entityID: 'event.front_door_doorbell',
+          oldState: createStateEntity({ state: '2026-05-24T12:00:00.000+00:00' }),
+          newState: createStateEntity({ state: '2026-05-24T12:00:05.123+00:00' }),
+        }),
+      ).toBe('signal');
+    });
+
+    it('returns null when there is no old state', () => {
+      expect(
+        getTriggerEventType({
+          entityID: 'event.front_door_doorbell',
+          newState: createStateEntity({ state: '2026-05-24T12:00:05.123+00:00' }),
+        }),
+      ).toBeNull();
+    });
+
+    it('returns null when the old state is unavailable (entity reconnecting)', () => {
+      expect(
+        getTriggerEventType({
+          entityID: 'event.front_door_doorbell',
+          oldState: createStateEntity({ state: 'unavailable' }),
+          newState: createStateEntity({ state: '2026-05-24T12:00:05.123+00:00' }),
+        }),
+      ).toBeNull();
+    });
+
+    it('returns "signal" when the old state is unknown (first fire after startup)', () => {
+      expect(
+        getTriggerEventType({
+          entityID: 'event.front_door_doorbell',
+          oldState: createStateEntity({ state: 'unknown' }),
+          newState: createStateEntity({ state: '2026-05-24T12:00:05.123+00:00' }),
+        }),
+      ).toBe('signal');
+    });
+
+    it.each([['unavailable'], ['unknown']])(
+      'returns null when the new state is %s',
+      (state: string) => {
+        expect(
+          getTriggerEventType({
+            entityID: 'event.front_door_doorbell',
+            oldState: createStateEntity({ state: '2026-05-24T12:00:00.000+00:00' }),
+            newState: createStateEntity({ state }),
+          }),
+        ).toBeNull();
+      },
+    );
+  });
+});