MatrixAttributes, ArgumentsAttributes, and Arrays

[mitchcapper]

Interestingly Arguments seems to be usable in much the same way Matrix can be used as:
public async Task MyTest([Arguments(["HI","Hello"])] String b) {}

generates matrix tests.

I do see several areas in the code though where matrixattribute is specifically checked and it doesn't look like Arguments gets converted somewhere so I am not sure what the full ramifications are. Clearly it doesn't support exclude.

Do to convenience features this:
public async Task MyTest( [Arguments(["HI","Hello"])] String[] b)

doesn't exactly do what one might expect, as it just matrix's it with two 1 item arrays.

In terms of actually using an array with Matrix/Arguments the syntax is a bit cumbersome:
[Matrix([new string[]{"Test1", "Test4"}])]

It was easy enough to write a MatrixArray attribute (and one could presumably do an ArgumentsArray attribute as well) like:

public class MatrixArrayAttribute(params object?[] objects) : MatrixAttribute {
	protected MatrixArrayAttribute(): this(null) {}

	public override object?[] GetObjects(DataGeneratorMetadata dataGeneratorMetadata) {
		return objects == null ? new object[1] : [objects];			
	}
}

and then if you just need to pass one value for the array you can use the basic syntax of:
public async Task MyTest( [MatrixArray(["HI","Hello"])] String[] b)

and its quite clean.

Using an overload one can even support N based test arrays, its a bit hacky but it works well. It even allows you to pass a null value to the parameter as long as it isn't the last value you pass.

public class MatrixArrayAttribute(object [] arr1,object [] arr2=null,object [] arr3=null,object [] arr4=null,object [] arr5=null,object [] arr6=null,object [] arr7=null,object [] arr8=null) : MatrixAttribute {

	protected MatrixArray2Attribute(): this(null) {	}
	private object [][] AllArrays => [arr1,arr2,arr3,arr4,arr5,arr6,arr7,arr8];

	public override object?[] GetObjects(DataGeneratorMetadata dataGeneratorMetadata) {

		var lastNotNullItem = AllArrays.LastIndexOfAnyExcept((object[])null);
		return lastNotNullItem == -1 ? new object[1] : AllArrays.Take(lastNotNullItem+1).ToArray();
	}
}

and it lets you continue to use the nice collection syntax:
[MatrixArray(["Test1", "Test4"],["Test1", "Test5"],["test9"])] string[] tests

Not sure its worth including in tunit but it can make some tests much easier to read. The same example currently requires:
[Matrix([new string[]{"Test1", "Test4"}],[new string[]{"Test1", "Test5"}],[new string[]{"test9"}])] string[] tests