You should stop doing this. The way to fix it is to use a project manager like pivotal tracker that allows the client to "accept" a feature. Then, in your contract, it states that the client must test features and that you are not responsible for bugs after acceptance.
Bugs in software happen. If you write tests, they happen less. All projects should expect some amount of bugs and these should be paid for as any other normal development work.
Theoretically, an immoral dev could take advantage of this and create a lot of bugs but they wouldn't be in business long, so they disappear. A bad dev who honestly creates too many bugs suffers the same fate.
You should stop doing this. The way to fix it is to use a project manager like pivotal tracker that allows the client to "accept" a feature. Then, in your contract, it states that the client must test features and that you are not responsible for bugs after acceptance.
Bugs in software happen. If you write tests, they happen less. All projects should expect some amount of bugs and these should be paid for as any other normal development work.
Theoretically, an immoral dev could take advantage of this and create a lot of bugs but they wouldn't be in business long, so they disappear. A bad dev who honestly creates too many bugs suffers the same fate.
Get paid for your work. Period.