Reg:Open GL API's testing

I need to test an Open GL API to ensure that it displays the way it claims to display. Eg: I want to ensure that a vertex is placed exactly at the coordinate position as given by the application.Are there any tetsing tools for this which gives can give me pixel view or so?

No.

OpenGL is not a pixel-perfect specification. It does not exactly specify the result of every computation. So it is entirely possible that two different implementations will come up with two slightly different results.