Add imap custom event data template (#93423)

* Add imap custom event template

* Add template validation

tests/components/imap/test_init.py

@@ -505,3 +505,57 @@ async def test_message_is_truncated(
 
     event_data = event_called[0].data
     assert len(event_data["text"]) == 3
+
+
+@pytest.mark.parametrize(
+    ("imap_search", "imap_fetch"),
+    [(TEST_SEARCH_RESPONSE, TEST_FETCH_RESPONSE_TEXT_PLAIN)],
+    ids=["plain"],
+)
+@pytest.mark.parametrize("imap_has_capability", [True, False], ids=["push", "poll"])
+@pytest.mark.parametrize(
+    ("custom_template", "result", "error"),
+    [
+        ("{{ subject }}", "Test subject", None),
+        ('{{ "@example.com" in sender }}', True, None),
+        ("{% bad template }}", None, "Error rendering imap custom template"),
+    ],
+    ids=["subject_test", "sender_filter", "template_error"],
+)
+async def test_custom_template(
+    hass: HomeAssistant,
+    mock_imap_protocol: MagicMock,
+    caplog: pytest.LogCaptureFixture,
+    custom_template: str,
+    result: str | bool | None,
+    error: str | None,
+) -> None:
+    """Test the custom template event data."""
+    event_called = async_capture_events(hass, "imap_content")
+
+    config = MOCK_CONFIG.copy()
+    config["custom_event_data_template"] = custom_template
+    config_entry = MockConfigEntry(domain=DOMAIN, data=config)
+    config_entry.add_to_hass(hass)
+    assert await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+    # Make sure we have had one update (when polling)
+    async_fire_time_changed(hass, utcnow() + timedelta(seconds=5))
+    await hass.async_block_till_done()
+    state = hass.states.get("sensor.imap_email_email_com")
+    # we should have received one message
+    assert state is not None
+    assert state.state == "1"
+
+    # we should have received one event
+    assert len(event_called) == 1
+    data: dict[str, Any] = event_called[0].data
+    assert data["server"] == "imap.server.com"
+    assert data["username"] == "email@email.com"
+    assert data["search"] == "UnSeen UnDeleted"
+    assert data["folder"] == "INBOX"
+    assert data["sender"] == "john.doe@example.com"
+    assert data["subject"] == "Test subject"
+    assert data["text"]
+    assert data["custom"] == result
+    assert error in caplog.text if error is not None else True