tensile test failure analysis (HELP)

[CHI3]

I need some help understanding TRUE tensile test failures.
How can you tell the difference between a coating tensile test failure and a glue tensile test failure?
Say for instance a set bond bars fail below the requirement and approx 50% of face failed at the glue interface (glue on each face of bond bar). What would be the failure?
Where can I find some literature to help me understand this more?
thank you in advance for any help.