How to easy fake cosmos client

[mingqishao]

Feature Request

We are using azcosmos package to talk with CosmosDB. We are struggling with mock the cosmos client for unit test. I'm wonder if the azcosmos SDK could provide a easy way to mock.

I found a usefully example from Compute SDK as reference: https://github.com/Azure/azure-sdk-for-go/blob/fake_prototype/sdk/resourcemanager/compute/armcompute/README.md#fakes

[ealsur]

@mingqishao If the fake package allows the creation of the Transport then it should be also available for azcosmos.

The Options on client creation let you set the Transport.

Just saw that the fakes is only available for ARM Compute. I wonder if this needs to be created for all SDKs?

@jhendrixMSFT Are there any other recommendations for external users to mock the transport or the SDKs?

[mingqishao]

I found a internal package in SDK github.com/Azure/azure-sdk-for-go/sdk/internal/mock. That will be very useful for us if you can expose this package. That allow use to easily mock any service's client.

[andrew-lis]

I don't want mocks. I want stubs for CosmosDb SDK
Fake implementations like the other MS team did:

• https://devblogs.microsoft.com/dotnet/fake-it-til-you-make-it-to-production/
• Microsoft.Extensions.Diagnostics.Testing

or remove sealed keywords so we can make these fakes/stub by over selves.

[RickWinter]

@Pilchie The cosmos sdk is hand written and would need to hand write the fakes to support this scenario. Joel can give guidance on the implementation if your team decides to add fakes.