diff --git a/packages/mdxui/core/tests/__mocks__/testing-library-react.ts b/packages/mdxui/core/tests/__mocks__/testing-library-react.ts
new file mode 100644
index 000000000..05b282501
--- /dev/null
+++ b/packages/mdxui/core/tests/__mocks__/testing-library-react.ts
@@ -0,0 +1,45 @@
+import React from 'react'
+
+function createDomNode(element: React.ReactElement): HTMLElement {
+  if (typeof element.type === 'function') {
+    return createDomNode(element.type(element.props))
+  }
+  const node = document.createElement(element.type as string)
+  const { children, className, ...rest } = element.props || {}
+  if (className) node.setAttribute('class', className)
+  Object.entries(rest).forEach(([k, v]) => {
+    if (v != null) node.setAttribute(k, String(v))
+  })
+  React.Children.toArray(children).forEach((child) => {
+    if (typeof child === 'string') {
+      node.appendChild(document.createTextNode(child))
+    } else {
+      node.appendChild(createDomNode(child as React.ReactElement))
+    }
+  })
+  return node
+}
+
+export function render(ui: React.ReactElement) {
+  const container = document.createElement('div')
+  container.appendChild(createDomNode(ui))
+  document.body.appendChild(container)
+  return { container }
+}
+
+export const screen = {
+  getByRole(role: string) {
+    return document.querySelector(`[role="${role}"]`) as HTMLElement
+  },
+  getByText(text: string) {
+    const walker = document.createTreeWalker(document.body, NodeFilter.SHOW_ELEMENT)
+    while (walker.nextNode()) {
+      const el = walker.currentNode as HTMLElement
+      if (el.textContent && el.textContent.includes(text)) return el
+    }
+    throw new Error('Element not found')
+  },
+  getByTestId(id: string) {
+    return document.querySelector(`[data-testid="${id}"]`) as HTMLElement
+  }
+}
diff --git a/packages/mdxui/core/tests/index.test.ts b/packages/mdxui/core/tests/index.test.ts
deleted file mode 100644
index 9d8fa7c94..000000000
--- a/packages/mdxui/core/tests/index.test.ts
+++ /dev/null
@@ -1,7 +0,0 @@
-import { describe, it, expect } from 'vitest'
-
-describe('mdxui package', () => {
-  it('should be importable', () => {
-    expect(true).toBe(true)
-  })
-})
diff --git a/packages/mdxui/core/tests/index.test.tsx b/packages/mdxui/core/tests/index.test.tsx
new file mode 100644
index 000000000..e526b428a
--- /dev/null
+++ b/packages/mdxui/core/tests/index.test.tsx
@@ -0,0 +1,30 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import React from 'react'
+import { Button } from '../components/button'
+import { Card } from '../components/card'
+import { Gradient } from '../components/gradient'
+
+describe('exported components', () => {
+  it('renders Button', () => {
+    render(<Button>Click me</Button>)
+    const button = document.querySelector('button')
+    expect(button).not.toBeNull()
+  })
+
+  it('renders Card', () => {
+    render(
+      <Card title="Test" href="https://example.com">
+        Card body
+      </Card>
+    )
+    const link = document.querySelector('a')
+    expect(link?.getAttribute('href')).to.contain('https://example.com')
+    expect(screen.getByText('Card body')).not.toBeNull()
+  })
+
+  it('renders Gradient', () => {
+    const { container } = render(<div><Gradient /></div>)
+    expect(container.querySelector('span')).not.toBeNull()
+  })
+})
diff --git a/packages/mdxui/core/tests/workflow.test.ts b/packages/mdxui/core/tests/workflow.test.ts
index eed43911f..a758bd3c1 100644
--- a/packages/mdxui/core/tests/workflow.test.ts
+++ b/packages/mdxui/core/tests/workflow.test.ts
@@ -1,33 +1,56 @@
 import { describe, it, expect } from 'vitest'
 import { z } from 'zod'
-import type { Step, Workflow } from '../workflow'
-
-describe('Workflow interfaces', () => {
-  it('should define Step interface correctly', () => {
-    const step: Step = {
-      id: 'test-step',
-      name: 'Test Step',
-      description: 'A test step',
+import type { Step, Workflow, WorkflowExecution } from '../workflow'
+
+async function executeStep<TInput, TOutput>(step: Step<TInput, TOutput>, input: TInput): Promise<TOutput> {
+  if (step.inputSchema) step.inputSchema.parse(input)
+  const result = await step.execute?.(input)
+  return step.outputSchema.parse(result)
+}
+
+describe('workflow utilities', () => {
+  it('executes a step with schema validation', async () => {
+    const step: Step<{ input: string }, { output: string }> = {
+      id: 'step',
+      name: 'Example',
       inputSchema: z.object({ input: z.string() }),
       outputSchema: z.object({ output: z.string() }),
+      execute: async (value) => ({ output: value.input.toUpperCase() }),
     }
 
-    expect(step.id).toBe('test-step')
-    expect(step.name).toBe('Test Step')
-    expect(step.inputSchema).toBeDefined()
-    expect(step.outputSchema).toBeDefined()
+    const result = await executeStep(step, { input: 'test' })
+    expect(result.output).toBe('TEST')
   })
 
-  it('should define Workflow interface correctly', () => {
-    const workflow: Workflow = {
-      id: 'test-workflow',
-      name: 'Test Workflow',
-      inputSchema: z.object({ start: z.string() }),
-      outputSchema: z.object({ end: z.string() }),
-      steps: [],
+  it('tracks workflow execution state', async () => {
+    const step: Step<undefined, string> = {
+      id: 's1',
+      name: 'first',
+      outputSchema: z.string(),
+      execute: async () => 'done',
+    }
+
+    const workflow: Workflow<undefined, string> = {
+      id: 'wf',
+      name: 'wf',
+      inputSchema: z.undefined(),
+      outputSchema: z.string(),
+      steps: [step],
     }
 
-    expect(workflow.id).toBe('test-workflow')
-    expect(workflow.steps).toEqual([])
+    const execution: WorkflowExecution<undefined, string> = {
+      workflow,
+      currentStepIndex: 0,
+      stepResults: {},
+      status: 'pending',
+    }
+
+    const output = await executeStep(workflow.steps[0], undefined)
+    execution.stepResults[step.id] = output
+    execution.currentStepIndex = 1
+    execution.status = 'completed'
+
+    expect(execution.stepResults[step.id]).toBe('done')
+    expect(execution.status).toBe('completed')
   })
 })
diff --git a/packages/mdxui/core/vitest.config.ts b/packages/mdxui/core/vitest.config.ts
index 9fd90ef52..0c25681d7 100644
--- a/packages/mdxui/core/vitest.config.ts
+++ b/packages/mdxui/core/vitest.config.ts
@@ -1,10 +1,15 @@
 import { defineConfig } from 'vitest/config'
 
 export default defineConfig({
+  resolve: {
+    alias: {
+      '@testing-library/react': new URL('./tests/__mocks__/testing-library-react.ts', import.meta.url).pathname,
+    },
+  },
   test: {
     globals: true,
     environment: 'jsdom',
-    include: ['src/**/*.test.{ts,tsx}'],
+    include: ['src/**/*.test.{ts,tsx}', 'tests/**/*.test.{ts,tsx}'],
     exclude: ['**/node_modules/**', '**/dist/**'],
     testTimeout: 300000,
     coverage: {