Coded UI Tests can fail for a number of reasons, producing detailed logs that can be used to rapidly identify what caused the failure.To enable this level of detail in the test results, open explorer and go to the following folder.
C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\
In this location you will find QTAgent32.exe.config. Before opening files in this directory, be sure that you have the permissions to edit and save files.
Locate the following section in the configuration file and set the “EqTraceLevel” to 4.
<system.diagnostics>
  <switches>
    <!– You must use integral values for “value”.
          Use 0 for off, 1 for error, 2 for warn, 3 for info, and 4 for verbose. –>
    <add name=EqtTraceLevelvalue=4/>
  </switches>
</system.diagnostics>
Then scroll down to the appSettings section and a key “EnableHttpLogger” with a value of “true”. Then add another key “EnableSnapshotInfo” with a value of “true
  <appSettings>
 
    <add key="EnableSnapshotInfo" value="true"/>
    <add key="EnableHttpLogger" value="true"/>
 
    <add key="StopTestRunCallTimeoutInSeconds" value="5"/>
    <add key="LogSizeLimitInMegs" value="20"/>
    <add key="CreateTraceListener" value="no"/>
    <add key="GetCollectorDataTimeout" value="300"/>
  </appSettings>



Now when you run a codedUI Test you will see there is an output link in the Test Explorer results
Which in turn will take you to the Test output containing the UITestActionLog.html
Which contains the CodeUI Test Log