Update md

Signed-off-by: Nnjupthan <hanhaibin@huawei.com>

zh-cn/application-dev/reference/apis/js-apis-application-testRunner.md

+# TestRunner
+
+> **说明**
+>
+> 本模块首批接口从API version 8开始支持。后续版本的新增接口，采用上角标单独标记接口的起始版本。
+
+## 导入模块
+
+```js
+import TestRunner from '@ohos.application.testRunner'
+```
+
+
+
+## TestRunner.onPrepare
+
+onPrepare(): void
+
+为运行测试用例准备单元测试环境
+
+**系统能力**：SystemCapability.Ability.AbilityRuntime.Core
+
+**示例：**
+
+```js
+export default class UserTestRunner extends TestRunner {
+    onPrepare() {
+        console.log("Trigger onPrepare")
+    }
+};
+```
+
+
+
+## TestRunner.onRun
+
+onRun(): void
+
+运行测试用例
+
+**系统能力**：SystemCapability.Ability.AbilityRuntime.Core
+
+**示例：**
+
+```js
+export default class UserTestRunner extends TestRunner {
+    onRun() {
+        console.log("Trigger onRun")
+    }
+};
+```
+
+
+
+
+
+
+
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+