ENH: Added test cases to ensure the behavior of integer as it is.
There is a need to add test case which ensure and maintain the behaviour
of integer. As per pr #3567, which speed up integer scalar's operations
by avoiding the conversion of integer to NumPy Scalar.
Added test case for size of long based of os
added int test for error raises
Removing test for OS choices on long conventions
ENH: Make the ndarray diagonal method return a view.

Also remove the test_diagonal_deprecation test and add test that
checks that a view is returned and that it is not writeable.

Closes #596.
Merge pull request #3645 from charris/enable-diagonal-as-view

ENH: Make the ndarray diagonal method return a view.
Merge pull request #3592 from arinkverma/int_behaviour

ENH: Added test cases to ensure the behavior of integer as it is.