[template/text] Fix lambda config (#6655)

Co-authored-by: Clyde Stubbs <2366188+clydebarrow@users.noreply.github.com>

tests/component_tests/text/test_text.py

@@ -54,3 +54,17 @@ def test_text_config_value_mode_set(generate_main):
     # Then
     assert "it_1->traits.set_mode(text::TEXT_MODE_TEXT);" in main_cpp
     assert "it_3->traits.set_mode(text::TEXT_MODE_PASSWORD);" in main_cpp
+
+
+def test_text_config_lamda_is_set(generate_main):
+    """
+    Test if lambda is set for lambda mode
+    """
+    # Given
+
+    # When
+    main_cpp = generate_main("tests/component_tests/text/test_text.yaml")
+
+    # Then
+    assert "it_4->set_template([=]() -> optional<std::string> {" in main_cpp
+    assert 'return std::string{"Hello"};' in main_cpp

tests/component_tests/text/test_text.yaml

@@ -31,3 +31,15 @@ text:
     optimistic: true
     internal: true
     max_length: 255
+
+  - platform: template
+    name: "test 4 key"
+    id: "it_4"
+    mode: text
+    set_action:
+      - then:
+          - logger.log:
+              format: Template text set to %s
+              args: ["x.c_str()"]
+    lambda: |
+      return std::string{"Hello"};