Update testing samples README files (#56)

add links to the Msft Docs to the sample READMEs

samples/README.md

@@ -4,6 +4,8 @@ This repository contains real-world examples that will walk you through differen
 
 ## Testing Best Practices
 
-- [Integration Testing](integration-testing/README.md)
-- [Compliance Testing](compliance-testing/README.md)
-- [End-to-end Testing](end-to-end-testing/README.md)
+> These samples are used as a support for the [Terraform on Azure testing best practices](https://docs.microsoft.com/azure/developer/terraform/best-practices-testing-overview) documentation section.
+
+- [Integration Testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-integration-testing)
+- [Compliance Testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-compliance-testing)
+- [End-to-end Testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-end-to-end-testing)

samples/compliance-testing/README.md

@@ -2,6 +2,8 @@
 
 Compliance testing, also known as Conformance testing, is a nonfunctional testing technique which is done to validate whether the system developed meets the organization’s prescribed standards or not. Most software teams do an analysis to check that the standards are properly enforced and implemented. Often working simultaneously to improve the standards, which will, in turn, lead to better quality.
 
+> Note: this sample is used as the support for the [Terraform on Azure - Compliance testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-compliance-testing) documentation.
+
 ## When to use Compliance Testing
 
 Compliance testing is performed to ensure the compliance of the deliverables of each phase of the development lifecycle. If you you have to enforce sufficient tests to validate the degree of compliance to the methodology and identify the violators. 

samples/end-to-end-testing/README.md

@@ -2,6 +2,8 @@
 
 This is an example of how to use [Terratest](https://github.com/gruntwork-io/terratest) to perform end-to-end testing on a Terraform project.
 
+> Note: this sample is used as the support for the [Terraform on Azure - End-to-end testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-end-to-end-testing) documentation.
+
 ## What about end-to-end testing
 
 End-to-end tests validate that a program actually works in real conditions, the closest as possible to production environment. Let's imagine that we are writing a Terraform module to deploy two virtual machines into a virtual network but we don't want those machines to be able to ping each other. End-to-end tests are exactly what we need to make sure that the deployment of this module create the expected resources, but also that the virtual machines cannot ping each other.

samples/integration-testing/README.md

@@ -2,6 +2,8 @@
 
 This is an example about the minimum level of integration testing that we recommend to be implemented on every Terraform project.
 
+> Note: this sample is used as the support for the [Terraform on Azure - Integration testing](https://docs.microsoft.com/azure/developer/terraform/best-practices-integration-testing) documentation.
+
 ## What about integration testing
 
 Testing is an important part of a software development project, and this is also for infrastructure as code projects. When working with Terraform, there are a bunch of tools that can help you to set up continuous integration quickly. Making sure that every time you and your colleagues are pushing changes, this code is automatically validated and tested.