Debugging DAX Calculations (teach to fish)

Thanks but that is part of the problem. The blogs do a good enough job of explaining the functions but not of showing how to validate functions are working as expected.

I think I developed some stuff in the last couple of hours that has helped but would love to hear anyone elses tricks patterns they use.

How to see values of a single column table output, within the context of a dimension?
 - Create table visual, drag a dimension column in first.
 - Create a new measure where you copy paste your table expression.

 - Wrap that table expression in concatentatex.

 - I want to evaluate these results of var _filter so I'll write measure [test_filter]

--here is the table variable from a much longer measure to evalute in a specific context:
var _filter = 
       FILTER(
            ALLSELECTED(
                Month[Fiscal Month Num Of Year]
            ),
            Month[Fiscal Month Num Of Year]
            <= selectedvalue( Month[Fiscal Month Num Of Year], 12 )
        )

--we write a new measure that looks like the following with concatenatex wrapping:
test5 filterv2 = 
    CONCATENATEX(
        FILTER(
            ALLSELECTED(
                Month[Fiscal Month Num Of Year]
            ),
            Month[Fiscal Month Num Of Year]
            <= selectedvalue( Month[Fiscal Month Num Of Year], 12 )
        ),
        'Month'[Fiscal Month Num Of Year],
        "-")

The result looks like this: