I am working on a project, on that project developers are doing a very good job that we hardly find the bugs on that application. Everything is running very smoothly client is very happy with the developers. but now client think that we are not reporting bugs & we are not doing anything which is not true Now how to handle this situation. How to explain this thing to the client.
While testing this application I'm sure you might have documented your test plan and also the cases you executed for testing.
If so, you can share those documents with the client saying these are the cases we have executed and also share with the client your test coverage data to show which areas and scenarios you have covered. From that the client will get an idea what testing was done for the application.
You can also go through the test cases yourself to see if you have missed anything or see if you can come up with more cases to test the application with. Also share this report once you're done testing.
That way client will know that the application was tested properly and not many issues were found during testing. So they won't complain why a huge list of bugs has not been reported to them.
I'd like to add another view of QA engineer.
Do you have story during development phase to tell your client? Do you add value to the product? I bet you do as Quality Assurance. Go tell them.
Since we should be a QA rather than a tester. We do assurance the quality of software and quality is not a thing that only measure after developer finish the last line of code. Actually, Quality need to be addressed before developer start the first line of code.
With team, QA grooms the client's requirements with a view of system impact, usability, UX, and etc. QA produces test approach for positive and negative scenario. We plan for performance and failure test. ... blah blah blah it's a lot of thing QA do to assurance the quality.
Even if none of a single test is fail when we did a test. But I think the things, QA did affect developer and the software somehow. Maybe developer had go over our test cases and realized he missed a detail. Then the discuss was arranged and developer did a fix before he shipped the software to test.
This is just an example. I believe you did and you do these things already. If this kind of client issue happen again. Go tell them, what is the value that you add to software, not only the test cases that you test against it.