由于找不到“createEvent”，纱线测试失败（create-react-app）

Question

我有一个使用 create-react-app 创建的简单反应项目。创建项目后，yarn test 命令工作正常，然后我开始添加一些实际的反应代码，最终在执行测试后出现此错误：

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PASS  src/test/App.test.js\n  \xe2\x9c\x93 renders without crashing (28ms)\n\nTest Suites: 1 passed, 1 total\nTests:       1 passed, 1 total\nSnapshots:   0 total\nTime:        0.729s, estimated 1s\nRan all test suites related to changed files.\n\nWatch Usage\n \xe2\x80\xba Press a to run all tests.\n \xe2\x80\xba Press p to filter by a filename regex pattern.\n \xe2\x80\xba Press t to filter by a test name regex pattern.\n \xe2\x80\xba Press q to quit watch mode.\n \xe2\x80\xba Press Enter to trigger a test run.\n/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-scripts/scripts/test.js:20\n  throw err;\n  ^\n\nTypeError: Cannot read property \'createEvent\' of undefined\n    at Object.invokeGuardedCallbackDev (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:577:25)\n    at invokeGuardedCallback (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:436:27)\n    at renderRoot (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:10386:7)\n    at performWorkOnRoot (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:11000:24)\n    at performWork (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:10952:7)\n    at requestWork (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:10861:7)\n    at scheduleWorkImpl (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:10744:11)\n    at scheduleWork (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:10706:12)\n    at Object.enqueueSetState (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react-dom/cjs/react-dom.development.js:6204:7)\n    at App.Object.<anonymous>.Component.setState (/Users/mpegorar/Development/SpringApps/fluxy_frontend/node_modules/react/cjs/react.development.js:226:16)\n    at then.then.jsonData (/Users/mpegorar/Development/SpringApps/fluxy_frontend/src/components/App.js:25:9)\n    at <anonymous>\n    at process._tickCallback (internal/process/next_tick.js:188:7)\nerror Command failed with exit code 1.\ninfo Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.\n

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测试实际上已执行，如果我在其中放入一些错误，它会发生变化，但工具会退出，而通常它会保持运行并继续根据代码执行测试。

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我的代码中似乎导致此错误的行是此处描述的设置状态：

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componentDidMount() {\n    const headers = new Headers()\n    headers.append(\'Content-Type\', \'application/hal+json\')\n\n    fetch(`${url}/listEnvironmentResources`, { headers }).then(\n        function(response){\n          return response.json();\n        }\n    ).then(jsonData => {\n      this.setState({environmentRecords: jsonData._embedded.environmentRecordResources});\n    });\n    }\n

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之前测试因为这个错误而无法工作，已针对接受的答案进行了修复。

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我发现的有关该错误的唯一参考是this，但它没有解决我的问题。

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知道如何解决这个问题吗？看起来像是缺少一些依赖项，但找不到哪个依赖项。

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