feat: introduce appendix section (#199)

Signed-off-by: Kavindu Dodanduwa <kavindudodanduwa@gmail.com>
Signed-off-by: Kavindu Dodanduwa <Kavindu-Dodan@users.noreply.github.com>
Signed-off-by: Todd Baert <todd.baert@dynatrace.com>
Co-authored-by: Todd Baert <todd.baert@dynatrace.com>
Co-authored-by: Federico Bond <federicobond@gmail.com>

specification/README.md

@@ -16,6 +16,7 @@ sidebar_position: 0
 - [Evaluation Context](./sections/03-evaluation-context.md)
 - [Hooks](./sections/04-hooks.md)
 - [Events](./sections/05-events.md)
+- [Appendix-A](./appendix-A.md)
 
 ## Conformance
 

specification/appendix-A.md

@@ -0,0 +1,38 @@
+---
+title: Appendix A: Included Utilities
+description: Information on OpenFeature ecosystem utilities
+sidebar_position: 4
+---
+
+# Appendix A: Included Utilities
+
+This document contains requirements for auxiliary utilities provided by the SDK, such as testing utilities.
+
+## In-memory provider
+
+> Language specific OpenFeature SDK implementations **SHOULD** expose an in-memory provider built into the SDK.
+
+The in-memory provider is intended to be used for testing, SDK consumers may use it for their use cases.
+Hence, the packaging, naming and access modifiers must be set appropriately.
+
+Given below are features this provider **MUST** support,
+
+- Provider must be initiated with a pre-defined set of flags provided to a constructor
+- Feature Flag structure must be minimal but should help testing OpenFeature specification
+- EvaluationContext support should be provided through callbacks/lambda expressions
+- Provider must support a means of updating flag values, resulting in the emission of `PROVIDER_CONFIGURATION_CHANGED` events
+- Provider must be maintained to support specification changes
+
+## SDK end-to-end testing
+
+> E2E tests must utilize [in-memory provider](#in-memory-provider) defined within the SDK and must be self-contained.
+
+OpenFeature project maintains end-to-end(e2e) test suite defined with [Gherkin syntax](https://cucumber.io/docs/gherkin/).
+These test definitions reside in the [OpenFeature test-harness](https://github.com/open-feature/test-harness) repository.
+
+```mermaid
+flowchart LR 
+    subgraph SDK 
+    A[e2e Tests] -.-> B[In-memory provider]
+    end
+```