* * * * *
                                        
                 Unit testing from inside an assembler, part V
                                        
I've made some major changes to my 6809 assembler [1], mostly to how the unit
testing works. The first change was to assemble the test code elsewhere far
in memory from the code being tested (there's a default value that can be
changed via an .OPT directive). This separation makes it easier to keep the
test code out of the final assembled artifact. The next change was to remove
the “unit test feature” as a distinct output type and make it work the rest
of the output formats (like the flat binary format, the Color Computer
executable format, or the Motorola SREC format [2]). But aside from the
internal changes, no changes were required of any existing 6809 assembly code
with tests.

And I didn't have to resort to embedding Lua to run the tests.

I consider that a success.

Less successful were the multiple attempts to come up with a table driven
format [3] to describe tests that wasted most of the time I spent on this so
far. I did devise a format I liked:

-----[ Assembly ]-----
	.test	"atod"
	.case atod /x := zero    /d =     0 , 'zero'
	.case atod /x := nine    /d =     9 , 'nine'
	.case atod /x := dechalf /d =  3276 , 'half'
	.case atod /x := decfull /d = 65535 , 'full'
	.case atod /x := none    /d =     0 , 'none'

zero		ascii	"0"z
nine		ascii	"9"z
dechalf		ascii	"3276"z
decfull		ascii	"65535"z
none		ascii	""z

	.endtst
-----[ END OF LINE ]-----

which would replace:

-----[ Assembly ]-----
	.test	"atod"
		ldx	#zero
		jsr	atod
	.assert	/d = 0 , 'zero'
		ldx	#nine
		jsr	atod
	.assert	/d = 9 , 'nine'
		ldx	#dechalf
		jsr	atod
	.assert	/d = 3276 , 'half'
		ldx	#decfull
		jsr	atod
	.assert	/d = 65535 , 'full'
		ldx	#none
		jsr	atod
	.assert	/d = 0 , 'none'
		rts
	.endtst
-----[ END OF LINE ]-----

Input parameters would be marked by the assignment operator “:=” so it would
be “easy” to distinguish pre-initializations with post-checks, but the word
“easy” is carry a lot of weight there. Any more inputs or outputs would
stretch the line out, and given that I don't support line continuations with
a “\” and have a hard line length limit, never mind the mini-Forth engine [4]
that handles the .ASSERT directives doesn't support assignment and is
“attached” to the 6809 emulator hitting a particular address and … yeah … I
see a lot of work ahead of me if I want to support this format.

More thinking is required.

[1] https://github.com/spc476/a09
[2] https://en.wikipedia.org/wiki/SREC_(file_format)
[3] gopher://gopher.conman.org/0Phlog:2024/10/13.2
[4] gopher://gopher.conman.org/0Phlog:2023/12/01.1

Email author at sean@conman.org

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