test: extract preview text assertion into named helper

Addresses review feedback:
https://github.com/Comfy-Org/ComfyUI_frontend/pull/11415#discussion_r3107682014

browser_tests/assets/execution/dynamic_combo_preview.json

@@ -0,0 +1,61 @@
+{
+  "id": "ef2b657e-8af3-42dd-9674-dde8a95adf22",
+  "revision": 0,
+  "last_node_id": 2,
+  "last_link_id": 1,
+  "nodes": [
+    {
+      "id": 1,
+      "type": "DynamicComboStringOutput",
+      "pos": [576, 441],
+      "size": [400, 200],
+      "flags": {},
+      "order": 0,
+      "mode": 0,
+      "inputs": [],
+      "outputs": [
+        {
+          "name": "output_text",
+          "type": "STRING",
+          "links": [1]
+        }
+      ],
+      "properties": {
+        "Node name for S&R": "DynamicComboStringOutput"
+      },
+      "widgets_values": ["test input", "on", 0.7, 64]
+    },
+    {
+      "id": 2,
+      "type": "PreviewAny",
+      "pos": [972, 458],
+      "size": [400, 200],
+      "flags": {},
+      "order": 1,
+      "mode": 0,
+      "inputs": [
+        {
+          "name": "source",
+          "type": "*",
+          "link": 1
+        }
+      ],
+      "outputs": [],
+      "properties": {
+        "Node name for S&R": "PreviewAny"
+      },
+      "widgets_values": []
+    }
+  ],
+  "links": [[1, 1, 0, 2, 0, "*"]],
+  "groups": [],
+  "config": {},
+  "extra": {
+    "frontendVersion": "1.19.1",
+    "ds": {
+      "offset": [0, 0],
+      "scale": 1
+    }
+  },
+  "version": 0.4
+}

browser_tests/tests/execution/dynamicComboPreview.spec.ts

@@ -0,0 +1,48 @@
+import { expect } from '@playwright/test'
+import type { Page } from '@playwright/test'
+
+import { comfyPageFixture as test } from '@e2e/fixtures/ComfyPage'
+
+const PREVIEW_TEXT_TIMEOUT_MS = 15_000
+
+const expectPreviewTextContains = async (page: Page, expected: string) => {
+  const previewTextbox = page.getByRole('textbox', { name: 'preview_text' })
+  await expect
+    .poll(async () => previewTextbox.inputValue(), {
+      timeout: PREVIEW_TEXT_TIMEOUT_MS
+    })
+    .toContain(expected)
+}
+
+test.describe(
+  'DynamicCombo text preview',
+  { tag: ['@workflow', '@subgraph'] },
+  () => {
+    test('shows text preview when DynamicCombo node is at top level', async ({
+      comfyPage
+    }) => {
+      await comfyPage.workflow.loadWorkflow('execution/dynamic_combo_preview')
+
+      await comfyPage.runButton.click()
+
+      await expectPreviewTextContains(comfyPage.page, 'DynamicCombo output')
+    })
+
+    test('shows text preview when DynamicCombo node is inside subgraph', async ({
+      comfyPage
+    }) => {
+      await comfyPage.workflow.loadWorkflow('execution/dynamic_combo_preview')
+
+      const sourceNode = await comfyPage.nodeOps.getNodeRefById('1')
+      await comfyPage.canvas.click()
+      await comfyPage.page.keyboard.press('Control+a')
+      const subgraphNode = await sourceNode.convertToSubgraph()
+
+      await comfyPage.runButton.click()
+
+      await subgraphNode.navigateIntoSubgraph()
+
+      await expectPreviewTextContains(comfyPage.page, 'DynamicCombo output')
+    })
+  }
+)

tools/devtools/nodes/__init__.py

@@ -8,6 +8,11 @@ from .errors import (
     NODE_CLASS_MAPPINGS as errors_class_mappings,
     NODE_DISPLAY_NAME_MAPPINGS as errors_display_name_mappings,
 )
+from .dynamic_combo import (
+    DynamicComboStringOutput,
+    NODE_CLASS_MAPPINGS as dynamic_combo_class_mappings,
+    NODE_DISPLAY_NAME_MAPPINGS as dynamic_combo_display_name_mappings,
+)
 from .inputs import (
     LongComboDropdown,
     NodeWithBooleanInput,
@@ -47,6 +52,7 @@ from .remote import (
 
 NODE_CLASS_MAPPINGS = {
     **errors_class_mappings,
+    **dynamic_combo_class_mappings,
     **inputs_class_mappings,
     **remote_class_mappings,
     **models_class_mappings,
@@ -54,6 +60,7 @@ NODE_CLASS_MAPPINGS = {
 
 NODE_DISPLAY_NAME_MAPPINGS = {
     **errors_display_name_mappings,
+    **dynamic_combo_display_name_mappings,
     **inputs_display_name_mappings,
     **remote_display_name_mappings,
     **models_display_name_mappings,
@@ -61,6 +68,7 @@ NODE_DISPLAY_NAME_MAPPINGS = {
 
 __all__ = [
     "DeprecatedNode",
+    "DynamicComboStringOutput",
     "DummyPatch",
     "ErrorRaiseNode",
     "ErrorRaiseNodeWithMessage",

tools/devtools/nodes/dynamic_combo.py

@@ -0,0 +1,48 @@
+from __future__ import annotations
+
+from comfy_api.latest import io  # pyright: ignore[reportMissingImports]
+
+
+class DynamicComboStringOutput(io.ComfyNode):
+    @classmethod
+    def define_schema(cls):
+        sampling_options = [
+            io.DynamicCombo.Option(
+                key="on",
+                inputs=[
+                    io.Float.Input("temperature", default=0.7, min=0.01, max=2.0),
+                    io.Int.Input("top_k", default=64, min=0, max=1000),
+                ],
+            ),
+            io.DynamicCombo.Option(key="off", inputs=[]),
+        ]
+
+        return io.Schema(
+            node_id="DynamicComboStringOutput",
+            category="DevTools",
+            inputs=[
+                io.String.Input("prompt", multiline=True, default="test input"),
+                io.DynamicCombo.Input("sampling_mode", options=sampling_options),
+            ],
+            outputs=[io.String.Output(display_name="output_text")],
+        )
+
+    @classmethod
+    def execute(cls, prompt, sampling_mode) -> io.NodeOutput:
+        mode = sampling_mode.get("sampling_mode", "unknown")
+        return io.NodeOutput(f"DynamicCombo output ({mode}): {prompt}")
+
+
+NODE_CLASS_MAPPINGS = {
+    "DynamicComboStringOutput": DynamicComboStringOutput,
+}
+
+NODE_DISPLAY_NAME_MAPPINGS = {
+    "DynamicComboStringOutput": "Dynamic Combo String Output",
+}
+
+__all__ = [
+    "DynamicComboStringOutput",
+    "NODE_CLASS_MAPPINGS",
+    "NODE_DISPLAY_NAME_MAPPINGS",
+]