Running tests that depend on string[] TypeDescriptor converters fail.

[NTaylorMullen]

Description

In MVC there's a ModelMetadata system that inspects types and tracks certain information about said types. One of the things it tracks is IsComplexType. It computes this by doing: !TypeDescriptor.GetConverter(ModelType).CanConvertFrom(typeof(string));, code for ref. This works for most scenarios but when ModelType is string[] IsComplexType ends up returning false when it should be true.

Looking through the vstest code it looks like it's due to how you guys register your converter for string arrays. The convert is a little too simple to handle string arrays properly.

This breaks the following MVC tests:

• https://github.com/aspnet/Mvc/blob/760c8f38678118734399c58c2dac981ea6e47046/test/Microsoft.AspNetCore.Mvc.IntegrationTests/KeyValuePairModelBinderIntegrationTest.cs#L503
• https://github.com/aspnet/Mvc/blob/760c8f38678118734399c58c2dac981ea6e47046/test/Microsoft.AspNetCore.Mvc.IntegrationTests/SimpleTypeModelBinderIntegrationTest.cs#L496

Working around this for now by skipping the test in core. This somehow works in net451 tests because the GetConverter call returns an array converter instead of the above mentioned CustomStringArrayConverter.

Steps to reproduce

• Download TypeDescriptorBug.zip
• cd TypeDescriptorBug
• dotnet restore
• dotnet test

Expected behavior

• Tests pass

Actual behavior

• Tests fail

Environment

.NET Command Line Tools (1.0.0-rc4-004616)

Product Information:
 Version:            1.0.0-rc4-004616
 Commit SHA-1 hash:  56d8071361

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.14393
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Users\nimullen\AppData\Local\Microsoft\dotnet\sdk\1.0.0-rc4-004616

[codito]

Triage: this issue is a core part of test platform, but there isn't a workaround. We should investigate the fix for this (may be for RTM).

[codito]

Fixed with b78eafa in master, bd04f21 in 15.0-rtm.