v5 How do I unit test my code when using Graph API

V5 of the Azure Graph API has removed the IGraphServiceClient and has methods that are not virtual. This makes mocking calls to the Graph API client extremely difficult as you have to mock the underlying Request Handler code (https://github.com/microsoftgraph/msgraph-sdk-dotnet/issues/1667).

Is there a recommended way to Mock calls to the GraphServiceClient in order for me to check my logic calling several Graph API methods.

For example, I have code like:

var userResponse = await _graphClient.Users.GetAsync(requestConfiguration =>
{
    requestConfiguration.QueryParameters.Select = new[] { "Id", "AccountEnabled" };
    requestConfiguration.QueryParameters.Filter = $"UserPrincipalName eq '{loginName}'";
    requestConfiguration.QueryParameters.Top = 1;
});

var azureUser = userResponse.Value.First();
if (azureUser.AccountEnabled == false)
{
    azureUser.AccountEnabled = true;
    await _graphClient.Users[azureUser.Id].PatchAsync(azureUser);
}

How would I go about mocking the GetAsync and PatchAsync methods?

Start by reading this issue and the related msgraph-sdk-dotnet issue #1667, then inspect how GraphServiceClient exposes GetAsync and PatchAsync in the shown example. Document a recommended way to mock these calls so the logic involving user lookup and account enabling can be tested.