Fix Cosmos DB tests

[munozemilio]

WriteAsync and ReadAsync CosmosDbStorage.cs implementations throw ArgumentNullException when passing null as object to store or keys to look for.
Test were broken since both were asserting a different behavior.

[coveralls]

Pull Request Test Coverage Report for Build 52984

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 75.985%

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Totals
Change from base Build 52909:	0.0%
Covered Lines:	4338
Relevant Lines:	5709

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💛 - Coveralls

[cleemullins]

No issues found in Microsoft.Bot.Builder.dll
No issues found in Microsoft.Bot.Builder.AI.Luis.dll
No issues found in Microsoft.Bot.Builder.AI.QnA.dll
No issues found in Microsoft.Bot.Builder.ApplicationInsights.dll
No issues found in Microsoft.Bot.Builder.Azure.dll
No issues found in Microsoft.Bot.Builder.Dialogs.dll
No issues found in Microsoft.Bot.Builder.TemplateManager.dll
No issues found in Microsoft.Bot.Configuration.dll
Compat issues with assembly Microsoft.Bot.Connector:
MembersMustExist : Member 'System.String Microsoft.Bot.Connector.Authentication.AuthenticationConstants.ToChannelFromBotLoginUrl' does not exist in the implementation but it does exist in the contract.

No issues found in Microsoft.Bot.Schema.dll

[cleemullins]

So...

Based on the tests, it's clear the behavior of the library has changed. The old behavior - which is more permissive and easier to deal with - seems the preferred behavior.

Rather than changing the tests to match the new behavior, can we update the code to make the old tests pass?

My thinking is that the expected behavior is that if I write "nothing" it should just work and not make me deal with Exeptions.

Same goes for "Read null", it should just return an empty set.

... both cases make my code easier to write and deal with.

[munozemilio]

Hi @cleemullins , that means revert @johnataylor commit, is that OK?

[cleemullins]

Spoke with @johnataylor . He convinced me. Merging.