Cleanup of fmt-tests buildfile organization and comments.

fmt-tests/basics/buildfile

@@ -1,16 +1,31 @@
 include ../test-main/
 
-#test_names =
-#  args-test \
-#  assert-test \
-#  base-test
-gtest_test_names = args-test assert-test base-test chrono-test color-test compile-fp-test compile-test format-test gtest-extra-test noexception-test os-test ostream-test printf-test std-test unicode-test xchar-test
+# NOTE: Maintaining explicit lists to match upstream, as it's not clear that there is intended to be a uniform pattern that can be reliably globbed.
+# See individual invocations of add_fmt_test() in upstream/test/CMakeLists.txt
 
-# header-only-test <- header only mode seemingly not supported by this build2 package?
-# scan-test <- some linker issues
-# posix-mock-test <- needs posix-mock.h, and has some msvc/runtime conditional logic going on
 
-standalone_test_names = enforce-checks-test # some way to pair these? -DFMT_ENFORCE_COMPILE_STRING
+# Tests that use gtest, and do not require any additional source/headers beyond a single cc file
+
+gtest_test_names =      \
+  args-test             \
+  assert-test           \
+  base-test             \
+  chrono-test           \
+  color-test            \
+  compile-fp-test       \
+  compile-test          \
+  format-test           \
+  gtest-extra-test      \
+  noexception-test      \
+  os-test               \
+  ostream-test          \
+  printf-test           \
+  std-test              \
+  unicode-test          \
+  xchar-test
+
+# NOTE: header-only-test - Excluded as this package does not currently provide support for FMT_HEADER_ONLY.
+# TODO: scan-test - Excluded due to unresolved linker errors.
 
 for test_name : $gtest_test_names
 {
@@ -21,25 +36,34 @@ for test_name : $gtest_test_names
   }
 }
 
+# END [Tests that use gtest, and do not require any additional source/headers beyond a single cc file]
+
+
+# Tests using gtest but with additional prerequisites
+
 ./: exe{ranges-test} : test/cxx{ranges-test ranges-odr-test}
 exe{ranges-test}: ../test-main/liba{test-main}:
 {
   bin.whole = true
 }
 
-# linker issues.
-#./: exe{scan-test} : test/cxx{scan-test} ../test-main/liba{test-main}
+# NOTE: format-impl-test- For whatever reason, format-impl-test is tied in upstream to header-only-test, which we do not support. Attempting to compile it alone yields errors, therefore omitted.
+# TODO: posix-mock-test - Excluded pending further work. Needs posix-mock.h, and has some msvc/runtime conditional logic that needs looking into.
+
+# END [Tests using gtest but with additional prerequisites]
 
-# @todo: cmake adds this test conditionally on NOT ( msvc AND fmt-shared )
-# in build2, i guess it's a bit different in that we can potentially build both shared and static variants within a single config?
-# also not clear how fmt_shared/fmt_header_only is being configured, looks like the package doesn't do anything there. using defaults only?
-# if $cxx. != msvc
-#./: exe{format-impl-test} : test/cxx{format-impl-test header-only-test} ../test-main/liba{test-main}
 
+# Tests which do not use gtest and therefore should link directly to fmt only and not the test-main lib
+
+# TODO: Is there a clean way to use a declarative list but with more structure, in order to pair names to additional options?
+standalone_test_names = \
+  enforce-checks-test           # -DFMT_ENFORCE_COMPILE_STRING
 
 import fmt = fmt%lib{fmt}
 
 for test_name : $standalone_test_names
 {
   ./: exe{$test_name} : test/cxx{$test_name} $fmt
 }
+
+# END [Tests which do not use gtest and therefore should link directly to fmt only and not the test-main lib]

fmt/tests/basics/buildfile

@@ -1,7 +1,5 @@
 import! [metadata, rule_hint=cxx.link] libs = fmt%lib{fmt}
 
-./ :
-
 ./ : exe{driver} : include = $($libs: fmt.has_header)
 ./ : exe{driver-modules} : include = $($libs: fmt.has_module)