title: TypeError: Cannot read property 'prepareStyles' of undefined
body: <p>My <code>Component</code> looks like  </p>
  
  <pre><code>import React, {PropTypes} from 'react';
  import TransactionListRow from './TransactionListRow';
  import {Table, TableBody, TableHeader, TableHeaderColumn, TableRow} from 'material-ui/Table';
  
  const TransactionList = ({transactions}) =&gt; {
    return (
      &lt;Table&gt;
        &lt;TableHeader displaySelectAll={false}&gt;
          &lt;TableRow&gt;
            &lt;TableHeaderColumn&gt;Name&lt;/TableHeaderColumn&gt;
            &lt;TableHeaderColumn&gt;Amount&lt;/TableHeaderColumn&gt;
            &lt;TableHeaderColumn&gt;Transaction&lt;/TableHeaderColumn&gt;
            &lt;TableHeaderColumn&gt;Category&lt;/TableHeaderColumn&gt;
          &lt;/TableRow&gt;
        &lt;/TableHeader&gt;
        &lt;TableBody&gt;
          {transactions.map(transaction =&gt;
            &lt;TransactionListRow key={transaction.id} transaction={transaction}/&gt;
          )}
        &lt;/TableBody&gt;
      &lt;/Table&gt;
    );
  };
  
  TransactionList.propTypes = {
    transactions: PropTypes.array.isRequired
  };
  
  export default TransactionList;
  </code></pre>
  
  <p>The test is  </p>
  
  <pre><code>import {mount} from 'enzyme';
  import TransactionList from './TransactionList';
  import {TableHeaderColumn} from 'material-ui/Table';
  import getMuiTheme from 'material-ui/styles/getMuiTheme';
  
  describe("&lt;TransactionList /&gt;", ()=&gt; {
    it('renders four &lt;TableHeaderColumn /&gt; components', () =&gt; {
      const wrapper = mount(&lt;TransactionList transactions={[]}/&gt;);
      expect(wrapper.find(TableHeaderColumn)).to.have.length(4);
    });
  });
  </code></pre>
  
  <p>My dependencies are  </p>
  
  <pre><code> "dependencies": {
      "babel-polyfill": "6.8.0",
      "bootstrap": "3.3.6",
      "jquery": "2.2.3",
      "react": "15.3.2",
      "react-dom": "15.3.2",
      "react-redux": "4.4.5",
      "react-router": "2.8.1",
      "react-router-redux": "4.0.6",
      "redux": "3.6.0",
      "redux-thunk": "2.1.0",
      "toastr": "2.1.2",
      "react-tap-event-plugin": "^1.0.0",
      "material-ui": "0.15.4"
    }
  </code></pre>
  
  <p>When I run test I see  </p>
  
  <pre><code> 1) &lt;TransactionList /&gt; renders four &lt;TableHeaderColumn /&gt; components:
       TypeError: Cannot read property 'prepareStyles' of undefined
        at Table.render (node_modules/material-ui/Table/Table.js:155:48)
        at node_modules/react/lib/ReactCompositeComponent.js:793:21
        at measureLifeCyclePerf (node_modules/react/lib/ReactCompositeComponent.js:74:12)
        at ReactCompositeComponentMixin._renderValidatedComponentWithoutOwnerOrContext (node_modules/react/lib/ReactCompositeComponent.js:792:27)
        at ReactCompositeComponentMixin._renderValidatedComponent (node_modules/react/lib/ReactCompositeComponent.js:819:34)
        at ReactCompositeComponentMixin.performInitialMount (node_modules/react/lib/ReactCompositeComponent.js:361:30)
        at ReactCompositeComponentMixin.mountComponent (node_modules/react/lib/ReactCompositeComponent.js:257:21)
        at Object.ReactReconciler.mountComponent (node_modules/react/lib/ReactReconciler.js:47:35)
        at ReactCompositeComponentMixin.performInitialMount (node_modules/react/lib/ReactCompositeComponent.js:370:34)
        at ReactCompositeComponentMixin.mountComponent (node_modules/react/lib/ReactCompositeComponent.js:257:21)
        at Object.ReactReconciler.mountComponent (node_modules/react/lib/ReactReconciler.js:47:35)
        at ReactCompositeComponentMixin.performInitialMount (node_modules/react/lib/ReactCompositeComponent.js:370:34)
        at ReactCompositeComponentMixin.mountComponent (node_modules/react/lib/ReactCompositeComponent.js:257:21)
        at Object.ReactReconciler.mountComponent (node_modules/react/lib/ReactReconciler.js:47:35)
        at ReactCompositeComponentMixin.performInitialMount (node_modules/react/lib/ReactCompositeComponent.js:370:34)
        at ReactCompositeComponentMixin.mountComponent (node_modules/react/lib/ReactCompositeComponent.js:257:21)
        at Object.ReactReconciler.mountComponent (node_modules/react/lib/ReactReconciler.js:47:35)
        at mountComponentIntoNode (node_modules/react/lib/ReactMount.js:105:32)
        at ReactReconcileTransaction.Mixin.perform (node_modules/react/lib/Transaction.js:138:20)
        at batchedMountComponentIntoNode (node_modules/react/lib/ReactMount.js:127:15)
        at ReactDefaultBatchingStrategyTransaction.Mixin.perform (node_modules/react/lib/Transaction.js:138:20)
        at Object.ReactDefaultBatchingStrategy.batchedUpdates (node_modules/react/lib/ReactDefaultBatchingStrategy.js:63:19)
        at Object.batchedUpdates (node_modules/react/lib/ReactUpdates.js:98:20)
        at Object.ReactMount._renderNewRootComponent (node_modules/react/lib/ReactMount.js:321:18)
        at Object.ReactMount._renderSubtreeIntoContainer (node_modules/react/lib/ReactMount.js:402:32)
        at Object.ReactMount.render (node_modules/react/lib/ReactMount.js:423:23)
        at Object.ReactTestUtils.renderIntoDocument (node_modules/react/lib/ReactTestUtils.js:84:21)
        at renderWithOptions (node_modules/enzyme/build/react-compat.js:175:26)
        at new ReactWrapper (node_modules/enzyme/build/ReactWrapper.js:87:59)
        at mount (node_modules/enzyme/build/mount.js:21:10)
        at Context.&lt;anonymous&gt; (TransactionList.test.js:7:1)
  </code></pre>
  
  <p>Please help me understand what is going wrong and how should I fix this? I am new to <code>React</code> and its ecosystem</p>