What's purpose of SAFEARRAYTests

[kant2002]

Maybe I miss something obvious, but SafeArrayTests are not testing anything.
I get that maybe SafeArray handling should be in VARIANTTests but they not there too. Do I miss something?

https://github.com/dotnet/winforms/blob/main/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Oleaut32/SAFEARRAYTests.cs

[RussKie]

I am not sure I can agree that these tests don't test anything. They test our definitions and implementations of SAFEARRAY are correct.
What is your concern?

[kant2002]

For me, this tests is testing internal details of SAFEaRRAY struct, and this is all looks like tests are testing how we apply marshaling attributes.

also this line

winforms/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Oleaut32/SAFEARRAYTests.cs

Line 93 in 9f77485

IntPtr pRecord = Marshal.GetComInterfaceForObject<CustomRecordInfo, IRecordInfo>(record);

when I decide to replace built-in Com usage I have to change that line which is meh, since i dislike changing tests.

for me seems to be tests better test some other areas which are used SAFEARRAY under the hood.

but I may miss other important context here.

[RussKie]

also this line

winforms/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Oleaut32/SAFEARRAYTests.cs

Line 93 in 9f77485

IntPtr pRecord = Marshal.GetComInterfaceForObject<CustomRecordInfo, IRecordInfo>(record);

when I decide to replace built-in Com usage I have to change that line which is meh, since i dislike changing tests.

Why do you think this line needs to be changed? CustomRecordInfo is a test private implementation of IRecordInfo, which isn't changing with the migration to COM Wrappers.
What am I missing?

[kant2002]

All modifications of SAFEARRAY struct happens via test only declarations

winforms/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Oleaut32/SAFEARRAYTests.cs

Lines 410 to 423 in 9f77485

	[DllImport(Libraries.Oleaut32, ExactSpelling = true)]
	private static unsafe extern SAFEARRAY* SafeArrayCreate(VARENUM vt, uint cDims, SAFEARRAYBOUND* rgsabound);
	[DllImport(Libraries.Oleaut32, ExactSpelling = true)]
	private static unsafe extern SAFEARRAY* SafeArrayCreateEx(VARENUM vt, uint cDims, SAFEARRAYBOUND* rgsabound, IntPtr pvExtra);
	[DllImport(Libraries.Oleaut32, ExactSpelling = true)]
	private static unsafe extern HRESULT SafeArrayDestroy(SAFEARRAY* psa);
	[DllImport(Libraries.Oleaut32, ExactSpelling = true)]
	private unsafe static extern HRESULT SafeArrayPutElement(SAFEARRAY* psa, int* rgIndices, void* pv);
	[DllImport(Libraries.Oleaut32, ExactSpelling = true)]
	private unsafe static extern HRESULT SafeArrayGetElement(SAFEARRAY* psa, int* rgIndices, void* pv);

Whole struct is almost regular struct with marshaling attributes applied. It is does not have behaviour. All modifications of that structs is via Win32 API. Obviously marshaling and Win32 is working. I cannot find WinForms specific functionality what is tested here. Maybe there was some historical reasons why this test appears?

SAFEARRAY struct used only to supplement Variant implementation. And these tests seems to cover more cases and do not rely on internal details too much. For example

winforms/src/System.Windows.Forms.Primitives/tests/UnitTests/Interop/Oleaut32/VARIANTTests.cs

Line 4317 in 9f77485

public void VARIANT_ToObject_ARRAYBOOLMultiDimension_ReturnsExpected(object result, bool[,] expected)