diff --git a/docs/testing/test-harness.md b/docs/testing/test-harness.md
index 365dc4d3..42f09837 100644
--- a/docs/testing/test-harness.md
+++ b/docs/testing/test-harness.md
@@ -46,6 +46,23 @@ The snapshot contains:
 
 Nested Components are included in the `tree` as Component snapshots as well.
 
+## Finding Nodes by Inspector Data
+
+Use `findByData()` and `findAllByData()` to find nodes with matching `inspector-data`.
+
+```xml
+<Text content="Menu" inspector-data="{testId: 'menu-title'}" />
+<Element inspector-data="{role: 'menu-item'}" />
+```
+
+```js
+const title = fixture.findByData('testId', 'menu-title')
+const items = fixture.findAllByData('role', 'menu-item')
+```
+
+`findByData(key, value)` returns the first matching node or `null`.
+`findAllByData(key, value)` returns all matching nodes, or an empty array when nothing matches.
+
 ## Updating Props and State
 
 Props can be updated with `setProps()`.
diff --git a/src/component.js b/src/component.js
index 71fbdd43..60648b20 100644
--- a/src/component.js
+++ b/src/component.js
@@ -38,6 +38,11 @@ import { plugins } from './plugin.js'
 
 // object to store global components
 let globalComponents
+let devMode = false
+
+export const setDevMode = (enabled) => {
+  devMode = enabled === true
+}
 
 const required = (name) => {
   throw new Error(`Parameter ${name} is required`)
@@ -493,7 +498,7 @@ const Component = (name = required('name'), config = required('config')) => {
     // one time code generation (only if precompilation is turned off)
     if (config.code === undefined) {
       Log.debug(`Generating code for ${name} component`)
-      config.code = codegenerator.call(config, parser(config.template, name))
+      config.code = codegenerator.call(config, parser(config.template, name), devMode)
     }
 
     // create an instance of the component, using base as the prototype (which contains Base)
diff --git a/src/testing/index.d.ts b/src/testing/index.d.ts
index 3f9f9a38..c392e2ad 100644
--- a/src/testing/index.d.ts
+++ b/src/testing/index.d.ts
@@ -43,6 +43,8 @@ export interface RenderComponentFixture {
   component: any
   root: any
   snapshot(): SnapshotNode | ComponentSnapshotNode
+  findByData(key: string, value: any): SnapshotNode | ComponentSnapshotNode | null
+  findAllByData(key: string, value: any): Array<SnapshotNode | ComponentSnapshotNode>
   setProps(props: Record<string, any>): void
   setState(state: Record<string, any>): void
   focus(event?: KeyboardEvent): Promise<any>
diff --git a/src/testing/renderComponent.js b/src/testing/renderComponent.js
index b0b585e5..5ffe39a7 100644
--- a/src/testing/renderComponent.js
+++ b/src/testing/renderComponent.js
@@ -17,12 +17,14 @@
 
 import Settings from '../settings.js'
 import { renderer, stage } from '../launch.js'
+import { setDevMode } from '../component.js'
 import symbols from '../lib/symbols.js'
 import { initLog } from '../lib/log.js'
 import { getRaw } from '../lib/reactivity/reactive.js'
 import Focus from '../focus/focus.js'
 import { initKeyMap, keyMap } from '../application.js'
 import { configurePlatform, platform } from '../platform.js'
+import { isObjectString, parseToObject } from '../lib/utils.js'
 import nodePlatform from './nodePlatform.js'
 
 let nodeId = 0
@@ -32,6 +34,7 @@ const renderComponent = (Component, options = {}) => {
   const originalPlatform = platform
 
   Settings.set(options.settings || {})
+  setDevMode(true)
   configurePlatform(() => nodePlatform())
   initLog()
   initKeyMap()
@@ -58,6 +61,27 @@ const renderComponent = (Component, options = {}) => {
     return componentSnapshot(component, holderMap)
   }
 
+  const findAllByData = (key, value) => {
+    const matches = []
+    visitSnapshot(snapshot(), (node) => {
+      if (node.attributes && node.attributes.data && node.attributes.data[key] === value) {
+        matches.push(node)
+      }
+    })
+    return matches
+  }
+
+  const findByData = (key, value) => {
+    let match = null
+    visitSnapshot(snapshot(), (node) => {
+      if (node.attributes && node.attributes.data && node.attributes.data[key] === value) {
+        match = node
+        return true
+      }
+    })
+    return match
+  }
+
   const setProps = (props = {}) => {
     const keys = Object.keys(props)
     for (let i = 0; i < keys.length; i++) {
@@ -107,6 +131,8 @@ const renderComponent = (Component, options = {}) => {
     component,
     root,
     snapshot,
+    findByData,
+    findAllByData,
     setProps,
     setState,
     focus,
@@ -289,10 +315,21 @@ const createElement = ({ parent } = {}) => {
       }
     },
     set(key, value) {
+      if (key === 'inspector-data') {
+        this.setInspectorMetadata(value)
+        return
+      }
       this.attributes[key] = value
       this.node[key] = value
     },
-    setInspectorMetadata() {},
+    setInspectorMetadata(data) {
+      if (isObjectString(data) === true) {
+        data = parseToObject(data)
+      }
+      if (data === null || typeof data !== 'object') return
+      this.attributes.data = { ...(this.attributes.data || {}), ...data }
+      this.node.data = { ...(this.node.data || {}), ...data }
+    },
     destroy() {
       this.eol = true
       this.children.length = 0
@@ -314,6 +351,19 @@ const appendToParent = (element, parent) => {
   }
 }
 
+const visitSnapshot = (node, visit) => {
+  if (node === undefined || node === null) return false
+  if (visit(node) === true) return true
+  if (node.type === 'Component') {
+    return visitSnapshot(node.tree, visit)
+  }
+  const children = node.children || []
+  for (let i = 0; i < children.length; i++) {
+    if (visitSnapshot(children[i], visit) === true) return true
+  }
+  return false
+}
+
 const createKeyboardEvent = (key, init = {}) => {
   const keyCode = init.keyCode || keyCodeFromKey(key)
   return platform.createKeyboardEvent('keydown', {
diff --git a/src/testing/renderComponent.test.js b/src/testing/renderComponent.test.js
index 9a459df8..d5bfb0f1 100644
--- a/src/testing/renderComponent.test.js
+++ b/src/testing/renderComponent.test.js
@@ -191,6 +191,36 @@ test('renderComponent setState updates state and reactive attributes in snapshot
   assert.end()
 })
 
+test('renderComponent finds nodes by inspector data', (assert) => {
+  const Menu = Component('InspectableMenu', {
+    template: `
+      <Element inspector-data="{testId: 'menu', role: 'menu'}">
+        <Text content="Menu" inspector-data="{testId: 'menu-title'}" />
+        <Element inspector-data="{role: 'menu-item'}" />
+        <Element inspector-data="{role: 'menu-item'}" />
+      </Element>
+    `,
+  })
+
+  const fixture = renderComponent(Menu)
+
+  assert.equal(
+    fixture.findByData('testId', 'menu-title').attributes.content,
+    'Menu',
+    'findByData should return the first node with matching inspector data'
+  )
+  assert.equal(
+    fixture.findAllByData('role', 'menu-item').length,
+    2,
+    'findAllByData should return all matching nodes'
+  )
+  assert.equal(fixture.findByData('testId', 'missing'), null, 'findByData should return null')
+  assert.deepEqual(fixture.findAllByData('role', 'missing'), [], 'findAllByData should return []')
+
+  fixture.destroy()
+  assert.end()
+})
+
 test('renderComponent snapshots nested component attributes and props separately', (assert) => {
   const Card = Component('Card', {
     template: `
@@ -263,6 +293,9 @@ test('renderComponent snapshots nested component attributes and props separately
             attributes: {
               x: 100,
               y: 20,
+              data: {
+                'blits-componentType': 'Card',
+              },
             },
             props: {
               title: 'Dune',