test: fix parser to prefer binop over unop, as coreutils does.

 remove bogus workaround in main(). rename atrocious variables/functions.
 much expand testsuite.
libbb: fix --help to not affect "test --help"

function                                             old     new   delta
run_applet_no_and_exit                               421     440     +19
nexpr                                                817     825      +8
static.no_op                                           -       6      +6
test_main                                            397     257    -140
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 2/1 up/down: 104/-211)         Total: -107 bytes

1 files changed, 13 insertions, 4 deletions

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
index eb98f1cd2..8c35450f8 100644
--- a/libbb/appletlib.c
+++ b/libbb/appletlib.c
@@ -196,8 +196,12 @@ void lbb_prepare(const char *applet
 #if ENABLE_FEATURE_INDIVIDUAL
         /* Redundant for busybox (run_applet_and_exit covers that case)
          * but needed for "individual applet" mode */
-        if (argv[1] && strcmp(argv[1], "--help") == 0)
-                bb_show_usage();
+        if (argv[1] && !argv[2] && strcmp(argv[1], "--help") == 0) {
+                /* Special case. POSIX says "test --help"
+                 * should be no different from e.g. "test --foo".  */
+                if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
+                        bb_show_usage();
+        }
 #endif
 }
 
@@ -715,8 +719,13 @@ void FAST_FUNC run_applet_no_and_exit(int applet_no, char **argv)
         xfunc_error_retval = EXIT_FAILURE;
 
         applet_name = APPLET_NAME(applet_no);
-        if (argc == 2 && !strcmp(argv[1], "--help"))
-                bb_show_usage();
+        if (argc == 2 && strcmp(argv[1], "--help") == 0) {
+                /* Special case. POSIX says "test --help"
+                 * should be no different from e.g. "test --foo".  */
+//TODO: just compare applet_no with APPLET_NO_test
+                if (!ENABLE_TEST || strcmp(applet_name, "test") != 0)
+                        bb_show_usage();
+        }
         if (ENABLE_FEATURE_SUID)
                 check_suid(applet_no);
         exit(applet_main[applet_no](argc, argv));