tablet is not changing from landscape to portrait and vice versa I want to test my application with  landscape to portrait but my tablet work only with landscabe and I don't know why ?
In certain tablets like my Nexus 7, the orientation can be locked as seen from one of Google search result:



Check under Settings to see whether any such setting is preventing your tablet to change orientation (landscape &lt;--> portrait). This can also be achieved quickly with a drop down from top left corner of the display. If other screens like the settings screen work and the app under test does not work, then it means that the app developer have constrained the orientation.

-- Added as an answer as Dan Hulme suggested.