MsSql = "Could not be translated", utests with InMemoryDatabase pass

[generik0]

Hi

I am a little worried about some matters in EF Core 3.0

I have a pile of repository pattern tests. All using the InMemoryDatabase. They are passing.
However the "real code" using a MsSql connections throw exceptions.
I.e. Issue with linq:

• Contains
• CompareTo
• Any

Housten (or should I write Redmond), do we have a problem?

[generik0]

Is there maybe an way I can add an event to my uTests, that all queries trigger a ToSql check?

[generik0]

The ".Equals(s, StringComparison.OrdinalIgnoreCase)" alos passes with in mem, but not for mssql

[generik0]

Hmm. I tried adding the DbCommandInterceptor, did not breakpoint on any of the overrides... But it is also in the relational namespace..

[smitpatel]

@generik0 - The first query seems like duplicate of #17342, we have fixed that for 3.1 release.
The second query - string equals method with StringComparison argument was never translated in EF Core. See #1222 which is tracking it and discussion why it is not easy to do. It was being evaluated in previous versions of EF, now it is throwing exception as EF Core 3.0 does not allow client evaluation.

[generik0]

HI @smitpatel . Thanks for answering! :-)

My point is not that EF Core 3.0 is failing for MS. That is what it is.

My point is that the Memory Db, is not falling for the queries that the real db is failing for.....

How can I use the Memory Db for testing, if we can not trust it behaves the same way when we query? 😨

In other words. if the memory db is to be used for testing, e.g. repos (which it was previously perfect for), then it should really fail here also...

Hence I have tried to add a question/be proactive: Van one add an interrupt (or something), that tests converting the memory db queries into a generic sql or something, so we can catch exceptions for the translations?

[generik0]

Again, if the mssql ef core LINQ fails for translations, the memory really also should too.. Otherwise, test with the memory db has no value at all... :-/
Does it make sense what I am trying to convey here?

[ajcvickers]

How can I use the Memory Db for testing, if we can not trust it behaves the same way when we query?

You can't. See the discussion here: #18457

[generik0]

@ajcvickers, oh, that is bad new. The InMemeroy Db rocked.. And a clear advantage when using the repo pattern and TDDing / integration tests...