In an agile environment, how does end-to-end testing fit within the continuous integration and continuous delivery (CI/CD) pipeline?

End-to-end testing typically fits just before deployment in the Continuous Delivery (CD) pipeline. In the CI/CD model, continuous integration deals with the frequent merging of code and running unit tests to ensure code integrity. The CD pipeline, on the other hand, ensures that the integrated code is consistently in a deployable state. End-to-end testing, which tests the flow of an application from start to finish, ensures that the system behaves as expected and identifies system-level issues before actual deployment.