解決了，原因是創建項目語言選擇錯誤，選了 kotlin，后來重新創建一個java的就成功了。另外還有adb.exe打開失敗問題，下載了adb的最新安裝包把文件替換了就解決了

01/30 18:29:55: Launching 'DemoTest()' on Android711.

Running tests

Starting Gradle Daemon...

Gradle Daemon started in 2 s 897 ms

> Configure project :app

WARNING:The option setting 'android.experimental.testOptions.emulatorSnapshots.maxSnapshotsForTestFailures=0' is experimental.

> Task :app:preBuild UP-TO-DATE

> Task :app:preDebugBuild UP-TO-DATE

> Task :app:compileDebugAidl NO-SOURCE

> Task :app:compileDebugRenderscript NO-SOURCE

> Task :app:generateDebugBuildConfig UP-TO-DATE

> Task :app:checkDebugAarMetadata UP-TO-DATE

> Task :app:generateDebugResValues UP-TO-DATE

> Task :app:generateDebugResources UP-TO-DATE

> Task :app:mergeDebugResources UP-TO-DATE

> Task :app:packageDebugResources UP-TO-DATE

> Task :app:parseDebugLocalResources UP-TO-DATE

> Task :app:createDebugCompatibleScreenManifests UP-TO-DATE

> Task :app:extractDeepLinksDebug UP-TO-DATE

> Task :app:processDebugMainManifest UP-TO-DATE

> Task :app:processDebugManifest UP-TO-DATE

> Task :app:processDebugManifestForPackage UP-TO-DATE

> Task :app:processDebugResources UP-TO-DATE

> Task :app:compileDebugKotlin UP-TO-DATE

> Task :app:javaPreCompileDebug UP-TO-DATE

> Task :app:compileDebugJavaWithJavac UP-TO-DATE

> Task :app:bundleDebugClasses UP-TO-DATE

> Task :app:preDebugAndroidTestBuild SKIPPED

> Task :app:compileDebugAndroidTestAidl NO-SOURCE

> Task :app:processDebugAndroidTestManifest UP-TO-DATE

> Task :app:generateDebugAndroidTestBuildConfig UP-TO-DATE

> Task :app:checkDebugAndroidTestAarMetadata UP-TO-DATE

> Task :app:compileDebugAndroidTestRenderscript NO-SOURCE

> Task :app:generateDebugAndroidTestResValues UP-TO-DATE

> Task :app:generateDebugAndroidTestResources UP-TO-DATE

> Task :app:mergeDebugAndroidTestResources UP-TO-DATE

> Task :app:processDebugAndroidTestResources UP-TO-DATE

> Task :app:compileDebugAndroidTestKotlin UP-TO-DATE

> Task :app:javaPreCompileDebugAndroidTest UP-TO-DATE

> Task :app:compileDebugAndroidTestJavaWithJavac

D:\Android\ASWorkspace\MKApplication\app\src\androidTest\java\com\mk\MKTest.java:5: 錯誤: 程序包android.support.test.uiautomator不存在

import android.support.test.uiautomator.UiDevice;

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?^

D:\Android\ASWorkspace\MKApplication\app\src\androidTest\java\com\mk\MKTest.java:16: 錯誤: 找不到符號

? ? public UiDevice mUidevice;

? ? ? ? ? ?^

? 符號:? ?類 UiDevice

? 位置: 類 MKTest

D:\Android\ASWorkspace\MKApplication\app\src\androidTest\java\com\mk\MKTest.java:13: 錯誤: 找不到符號

@RunWith(AndriodJUnit4.class)

? ? ? ? ?^

? 符號: 類 AndriodJUnit4

D:\Android\ASWorkspace\MKApplication\app\src\androidTest\java\com\mk\MKTest.java:21: 錯誤: 找不到符號

? ? ? ? mUidevice= UiDevice.getInstance(mInstrumentation);

? ? ? ? ? ? ? ? ? ?^

? 符號:? ?變量 UiDevice

? 位置: 類 MKTest

4 個錯誤

> Task :app:compileDebugAndroidTestJavaWithJavac FAILED

25 actionable tasks: 1 executed, 24 up-to-date

FAILURE: Build failed with an exception.

* What went wrong:

Execution failed for task ':app:compileDebugAndroidTestJavaWithJavac'.

> Compilation failed; see the compiler error output for details.

* Try:

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 16s