Contrib tests were broken back in 23ad634a evidently, just now noticing...

In 2019 it's different: https://www.appveyor.com/docs/services-databases/#sql-server-2019

We should centralize these, but at least remove them from code for now.

I'll do a TestConfig pass on Dapper here as a follow-up.

I add update `Set` method and unit test.

e.g: 
```C#
var sb = new SqlBuilder()
       .Set("vip = @vip", new { vip })
       .Set("updatetime = @updatetime", new { updatetime })
       .Where("id = @id", new { id })
;
var template = sb.AddTemplate("update #Users /**set**/ /**where**/");
connection.Execute(template.RawSql, template.Parameters);
```

RawSql will generate :　
```
update #Users Set vip = @vip , updatetime = @updatetime\n WHERE id = @id\n
```

using Dapper Execute in sqlserver it'll reqeust by below sql command
```
exec sp_executesql N'update #Users Set vip = @vip , updatetime = @updatetime
 WHERE id = @id
',N'@vip bit,@updatetime datetime,@id int',@vip=1,@updatetime='2020-01-01 00:00:00',@id=1
```
Co-authored-by: Nick Craver <nrcraver@gmail.com>
Co-authored-by: Nick Craver <craver@stackoverflow.com>

`SingleOrDefault<(int, int)?>(query)` always returned null because the IsValueTuple did not handle nullable types and thus the `GenerateValueTupleDeserializer` method was never called.

I've added test for the case when the query does not return something (the tuple should be null) and when it does return something. Additionally added tests for the edge-case where you select 8 or 15 element tuples to make sure nothing broke there. 

* Added EF6 tests in netcoreapp3.0

* Fix up EF Core ref to always be 6.3.0
Co-authored-by: Alex Bagnolini <alex.bagnolini@ericsoft.com>
Co-authored-by: Nick Craver <craver@stackoverflow.com>

Co-authored-by: Youssef Victor <31348972+Youssef1313@users.noreply.github.com>

Fix small typo and grammar

We are now providing it programmatically so we don't disrupt SQL Server.

The comment suggested that more than the number specified in InListStringSplitCount and it would start to use string_split.  However, it is greater-than-or-equal-to (GTE) the number specified by InListStringSplitCount.

* - enable deterministic build
- lib updates for core packages

* set source root if needed

* Restore VS test runner

xUnit won't run in VS without it :)
Co-authored-by: Nick Craver <craver@stackoverflow.com>

In Sqlite, DateTime is stored as String, and custom serializers ultimately use Convert.ChangeType to do the conversion. The generated code however doesn't set the Invariant culture, and the conversion can fail if the current culture doesn't match the standard DateTime serialization format from Sqlite.

* Use loop variable instead of 0

* Changed unit test, added additional nesting level

framework and tooling lib updates; does *NOT* include the full corpus of 3rd party ADO.NET providers

This is a branch cleaning up old `#if` clauses, `.csproj` bits, Linux build compatibility, and a few other tid-bits (broken out by commit).

In general: we're on 3.0 tooling and all previous cruft has been removed.

…cording to their names.

Hand coded version did not operate under the same circumstances as others.

- Add CommandBehavior.SingleResult and CommandBehavior.SingleRow. All other framworks does this under the hood.
- Run SqlCommand.Prepare() (perhaps it should be benchmarked as "Compiled"?)
- Use GetNullableValue because it's easier to read and slightly faster
- _table.Rows was incrementally added, which made the benchmark run slower the longer it executed. Added _table.Rows.Clear() to prevent the growth.
- Changed select to use * like other benchmarks