[api] Cover Home Assistant action fields in the api test config (#20236)

tests/components/api/common-base.yaml

@@ -149,6 +149,38 @@ api:
                   args:
                     - error.c_str()
                     - name.c_str()
+    # Constant and lambda fields mixed in one action, with lambdas of several
+    # return types reading the trigger args, and a templated action name
+    - action: test_homeassistant_fields
+      variables:
+        room: string
+        level: int
+      then:
+        - homeassistant.action:
+            action: !lambda 'return std::string("light.") + (level > 0 ? "turn_on" : "turn_off");'
+            data:
+              entity_id: light.living_room
+              brightness: !lambda 'return level;'
+            data_template:
+              message: "{{ room }} is at {{ level }}"
+            variables:
+              room: !lambda 'return room.c_str();'
+              level: !lambda 'static char buf[12]; snprintf(buf, sizeof(buf), "%d", level); return buf;'
+        - homeassistant.action:
+            action: notify.html5
+            data:
+              message: Button was pressed
+        # Same constant fields as above, so codegen can share them
+        - homeassistant.action:
+            action: notify.html5
+            data:
+              message: Button was pressed
+        - homeassistant.event:
+            event: esphome.room_level
+            data:
+              room: !lambda 'return room;'
+              ratio: !lambda 'return level / 100.0f;'
+        - homeassistant.tag_scanned: !lambda 'return room;'
     # Test ContinuationAction (IfAction with then/else branches)
     - action: test_if_action
       variables: