Add Smoke Testing to the CI pipeline

[jlvoiseux]

Following the deployment of a broken release (v1.0.1), it has been suggested to introduce smoke testing to the repository. These smoke tests would take inspiration from elastic-lambda-extension-testing and would be implemented via Terraform. A possible process outline would be as follows:

• Build the Lambda layer
• Spin up an APM-instrumented Lambda function behind an API Gateway
• Attach the extension layer to the function
• Perform 2 invocations (in order to also check metrics generation)
• Check a dedicated ES instance for the presence of target documents

An implementation of SAM CLI-based E2E testing already exists, but since the SAM CLI does not support the Lambda Logs API used for Metrics, its relevance will decrease by the time we release v1.1.

[axw]

We might want to take some inspiration from https://github.com/cyrille-leclerc/my-serverless-shopping-cart/tree/main/checkout-function/deploy, which uses https://registry.terraform.io/modules/terraform-aws-modules/lambda/aws/latest

[simitt]

@cachedout would someone from your team be able to help out with the CI setup for the newly added smoke tests once #296 is finalized)?

[axw]

Reopening this - we can close it once the CI integration has been done.

[cachedout]

@cachedout would someone from your team be able to help out with the CI setup for the newly added smoke tests once #296 is finalized)?

@simitt Apologies, this one slipped through my filters. It looks like this has been done by @kruskall in #310 and that it's currently under review. Is there anything needed beyond that?