[template] Fix misleading 'Text value too long to save' warning (#14753)

tests/integration/fixtures/template_text_save.yaml

@@ -0,0 +1,23 @@
+esphome:
+  name: host-template-text-save-test
+
+host:
+
+api:
+  batch_delay: 0ms
+
+logger:
+
+preferences:
+  flash_write_interval: 0s
+
+text:
+  - platform: template
+    name: "Test Text Restore"
+    id: test_text_restore
+    optimistic: true
+    min_length: 0
+    max_length: 10
+    mode: text
+    initial_value: "hello"
+    restore_value: true

tests/integration/test_template_text_save.py

@@ -0,0 +1,131 @@
+"""Integration test for template text restore_value persistence.
+
+Tests that:
+1. A template text with restore_value saves its value to preferences
+2. The saved value persists across restarts (binary re-run)
+3. Setting the same value again does not produce a spurious "too long" warning
+"""
+
+from __future__ import annotations
+
+import asyncio
+from pathlib import Path
+import socket
+from typing import Any
+
+from aioesphomeapi import TextInfo, TextState
+import pytest
+
+from .conftest import run_binary_and_wait_for_port, wait_and_connect_api_client
+from .state_utils import InitialStateHelper, require_entity
+from .types import CompileFunction, ConfigWriter
+
+
+@pytest.mark.asyncio
+async def test_template_text_save(
+    yaml_config: str,
+    write_yaml_config: ConfigWriter,
+    compile_esphome: CompileFunction,
+    reserved_tcp_port: tuple[int, socket.socket],
+) -> None:
+    """Test template text save/restore persistence and duplicate-save behavior."""
+    port, port_socket = reserved_tcp_port
+
+    # Clean up any stale preference file from previous runs
+    prefs_file = (
+        Path.home() / ".esphome" / "prefs" / "host-template-text-save-test.prefs"
+    )
+    if prefs_file.exists():
+        prefs_file.unlink()
+
+    # Write and compile once
+    config_path = await write_yaml_config(yaml_config)
+    binary_path = await compile_esphome(config_path)
+
+    # Release the reserved port so the binary can bind to it
+    port_socket.close()
+
+    # --- First run: set a value and verify no spurious warnings ---
+    warning_lines: list[str] = []
+
+    def capture_warnings(line: str) -> None:
+        if "too long to save" in line.lower():
+            warning_lines.append(line)
+
+    async with (
+        run_binary_and_wait_for_port(
+            binary_path, "127.0.0.1", port, line_callback=capture_warnings
+        ),
+        wait_and_connect_api_client(port=port) as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info.name == "host-template-text-save-test"
+
+        entities, _ = await client.list_entities_services()
+        text_entity = require_entity(
+            entities, "test_text_restore", TextInfo, "Test Text Restore"
+        )
+
+        # Set up state tracking
+        loop = asyncio.get_running_loop()
+        state_futures: dict[int, asyncio.Future[Any]] = {}
+
+        def on_state(state: Any) -> None:
+            if state.key in state_futures and not state_futures[state.key].done():
+                state_futures[state.key].set_result(state)
+
+        initial_state_helper = InitialStateHelper(entities)
+        client.subscribe_states(initial_state_helper.on_state_wrapper(on_state))
+        await initial_state_helper.wait_for_initial_states()
+
+        # Verify initial value from config
+        initial = initial_state_helper.initial_states[text_entity.key]
+        assert isinstance(initial, TextState)
+        assert initial.state == "hello"
+
+        async def wait_for_state(key: int, timeout: float = 2.0) -> Any:
+            state_futures[key] = loop.create_future()
+            try:
+                return await asyncio.wait_for(state_futures[key], timeout)
+            finally:
+                state_futures.pop(key, None)
+
+        # Set a new value that fits within max_length
+        client.text_command(key=text_entity.key, state="world")
+        state = await wait_for_state(text_entity.key)
+        assert state.state == "world"
+
+        # Set the same value again - should NOT produce "too long" warning
+        client.text_command(key=text_entity.key, state="world")
+        # Give time for the warning to appear (if any)
+        await asyncio.sleep(0.5)
+
+    # No warnings should have appeared
+    assert warning_lines == [], (
+        f"Unexpected 'too long to save' warning(s): {warning_lines}"
+    )
+
+    # --- Second run: verify the value was restored from preferences ---
+    async with (
+        run_binary_and_wait_for_port(binary_path, "127.0.0.1", port),
+        wait_and_connect_api_client(port=port) as client,
+    ):
+        entities, _ = await client.list_entities_services()
+        text_entity = require_entity(
+            entities, "test_text_restore", TextInfo, "Test Text Restore"
+        )
+
+        initial_state_helper = InitialStateHelper(entities)
+        client.subscribe_states(initial_state_helper.on_state_wrapper(lambda s: None))
+        await initial_state_helper.wait_for_initial_states()
+
+        # The value should be "world" - restored from preferences
+        restored = initial_state_helper.initial_states[text_entity.key]
+        assert isinstance(restored, TextState)
+        assert restored.state == "world", (
+            f"Expected restored value 'world', got '{restored.state}'"
+        )
+
+    # Clean up preference file
+    if prefs_file.exists():
+        prefs_file.unlink()