document the undocumented test/asm/listing behaviours

test/asm/listing/readme.txt

@@ -6,22 +6,38 @@ The name of a test is everything in the form <test>.s.
 
 The following reference files can be added:
 
-- <test>.bin-ref:
+- ref/<test>.bin-ref:
   This is a reference for the resulting binary.
   The binary as binary tested against this file.
   If they are not equal, the test fails.
 
-- <test>.list-ref
+- ref/<test>.list-ref
   This is a reference for the resulting listing output
   This file *must* have the first line of the listing removed, as that
   contains a ca65 version string, and almost always this will be changed!
 
+- ref/<test>.err-ref
+  This is a reference for the resulting ca65 stdout (>) output.
+
+- ref/<test>.err2-ref
+  This is a reference for the resulting ca65 stderr (2>) output.
+
+- ref/<test>.ld65err-ref
+  This is a reference for the resutling ld65 stdout (>) output.
+
+- ref/<test>.ld65err2-ref
+  This is a reference for the resulting ld65 stderr (2>) output.
+
+The following control files can be added to control the tests.
+These files are empty (contents ignored), and only the filename is used:
+
+- control/<test>.err
+  Test is expected to produce an error.
+
+- control/<test>.no-ld65
+  Skip the ld65 step.
+
 
 Note that the resulting .bin file is generated twice: Once with no listing
 file, and once with listing file. This way, one can find out if the listing
 file generation changes anything with the resulting binary output.
-
-
-TODO:
-- add the possibility to test for specific error output that are to be
-  expected