End-to-End testing

[estolfo]

These tests will involve using an aws lambda function, the extension, an apm agent, and an apm server. They'll verify that a function can be instrumented, the data is sent to and forwarded by the extension, and that the apm server receives the data. We researched doing these tests using LocalStack but concluded that it's insufficient so we'll use aws for these tests.

• Short term: we'll do these tests manually using any agent. So far, these tests have been done with the java, ruby, nodejs, and python agents.
• Long term: we'll use (terraform|CloudFormation?) to create an aws lambda, add the extension as a layer, invoke the function, verify that the data is sent to the apm server. We might want to write a mock apm server for this.