Today adb command to install apk,prompted the following error:.
Failure [INSTALL_FAILED_TEST_ONLY: installPackageLI]

Solution:
Method 1:
Change android:testOnly=”true” to android:testOnly=”false” in AndroidManifest.xml, or just remove it.
Method 2:
adb push .apk /tmp
adb shell pm install -t /tmp/.apk
Method 3:
adb install -t *.apk