testing: kselftest_harness: add filtering and enumerating tests

As the number of test cases and length of execution grows it's
useful to select only a subset of tests. In TLS for instance we
have a matrix of variants for different crypto protocols and
during development mostly care about testing a handful.
This is quicker and makes reading output easier.

This patch adds argument parsing to kselftest_harness.

It supports a couple of ways to filter things, I could not come
up with one way which will cover all cases.

The first and simplest switch is -r which takes the name of
a test to run (can be specified multiple times). For example:

  $ ./my_test -r some.test.name -r some.other.name

will run tests some.test.name and some.other.name (where "some"
is the fixture, "test" and "other" and "name is the test.)

Then there is a handful of group filtering options. f/v/t for
filtering by fixture/variant/test. They have both positive
(match -> run) and negative versions (match -> skip).
If user specifies any positive option we assume the default
is not to run the tests. If only negative options are set
we assume the tests are supposed to be run by default.

  Usage: ./tools/testing/selftests/net/tls [-h|-l] [-t|-T|-v|-V|-f|-F|-r name]
	-h       print help
	-l       list all tests

	-t name  include test
	-T name  exclude test
	-v name  include variant
	-V name  exclude variant
	-f name  include fixture
	-F name  exclude fixture
	-r name  run specified test

  Test filter options can be specified multiple times. The filtering stops
  at the first match. For example to include all tests from variant 'bla'
  but not test 'foo' specify '-T foo -v bla'.

Here we can request for example all tests from fixture "foo" to run:

 ./my_test -f foo

or to skip variants var1 and var2:

 ./my_test -V var1 -V var2
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/kselftest_harness.h

@@ -54,6 +54,7 @@
 #define _GNU_SOURCE
 #endif
 #include <asm/types.h>
+#include <ctype.h>
 #include <errno.h>
 #include <stdbool.h>
 #include <stdint.h>
@@ -985,6 +986,127 @@ void __wait_for_test(struct __test_metadata *t)
 	}
 }
 
+static void test_harness_list_tests(void)
+{
+	struct __fixture_variant_metadata *v;
+	struct __fixture_metadata *f;
+	struct __test_metadata *t;
+
+	for (f = __fixture_list; f; f = f->next) {
+		v = f->variant;
+		t = f->tests;
+
+		if (f == __fixture_list)
+			fprintf(stderr, "%-20s %-25s %s\n",
+				"# FIXTURE", "VARIANT", "TEST");
+		else
+			fprintf(stderr, "--------------------------------------------------------------------------------\n");
+
+		do {
+			fprintf(stderr, "%-20s %-25s %s\n",
+				t == f->tests ? f->name : "",
+				v ? v->name : "",
+				t ? t->name : "");
+
+			v = v ? v->next : NULL;
+			t = t ? t->next : NULL;
+		} while (v || t);
+	}
+}
+
+static int test_harness_argv_check(int argc, char **argv)
+{
+	int opt;
+
+	while ((opt = getopt(argc, argv, "hlF:f:V:v:t:T:r:")) != -1) {
+		switch (opt) {
+		case 'f':
+		case 'F':
+		case 'v':
+		case 'V':
+		case 't':
+		case 'T':
+		case 'r':
+			break;
+		case 'l':
+			test_harness_list_tests();
+			return KSFT_SKIP;
+		case 'h':
+		default:
+			fprintf(stderr,
+				"Usage: %s [-h|-l] [-t|-T|-v|-V|-f|-F|-r name]\n"
+				"\t-h       print help\n"
+				"\t-l       list all tests\n"
+				"\n"
+				"\t-t name  include test\n"
+				"\t-T name  exclude test\n"
+				"\t-v name  include variant\n"
+				"\t-V name  exclude variant\n"
+				"\t-f name  include fixture\n"
+				"\t-F name  exclude fixture\n"
+				"\t-r name  run specified test\n"
+				"\n"
+				"Test filter options can be specified "
+				"multiple times. The filtering stops\n"
+				"at the first match. For example to "
+				"include all tests from variant 'bla'\n"
+				"but not test 'foo' specify '-T foo -v bla'.\n"
+				"", argv[0]);
+			return opt == 'h' ? KSFT_SKIP : KSFT_FAIL;
+		}
+	}
+
+	return KSFT_PASS;
+}
+
+static bool test_enabled(int argc, char **argv,
+			 struct __fixture_metadata *f,
+			 struct __fixture_variant_metadata *v,
+			 struct __test_metadata *t)
+{
+	unsigned int flen = 0, vlen = 0, tlen = 0;
+	bool has_positive = false;
+	int opt;
+
+	optind = 1;
+	while ((opt = getopt(argc, argv, "F:f:V:v:t:T:r:")) != -1) {
+		has_positive |= islower(opt);
+
+		switch (tolower(opt)) {
+		case 't':
+			if (!strcmp(t->name, optarg))
+				return islower(opt);
+			break;
+		case 'f':
+			if (!strcmp(f->name, optarg))
+				return islower(opt);
+			break;
+		case 'v':
+			if (!strcmp(v->name, optarg))
+				return islower(opt);
+			break;
+		case 'r':
+			if (!tlen) {
+				flen = strlen(f->name);
+				vlen = strlen(v->name);
+				tlen = strlen(t->name);
+			}
+			if (strlen(optarg) == flen + 1 + vlen + !!vlen + tlen &&
+			    !strncmp(f->name, &optarg[0], flen) &&
+			    !strncmp(v->name, &optarg[flen + 1], vlen) &&
+			    !strncmp(t->name, &optarg[flen + 1 + vlen + !!vlen], tlen))
+				return true;
+			break;
+		}
+	}
+
+	/*
+	 * If there are no positive tests then we assume user just wants
+	 * exclusions and everything else is a pass.
+	 */
+	return !has_positive;
+}
+
 void __run_test(struct __fixture_metadata *f,
 		struct __fixture_variant_metadata *variant,
 		struct __test_metadata *t)
@@ -1032,24 +1154,32 @@ void __run_test(struct __fixture_metadata *f,
 			f->name, variant->name[0] ? "." : "", variant->name, t->name);
 }
 
-static int test_harness_run(int __attribute__((unused)) argc,
-			    char __attribute__((unused)) **argv)
+static int test_harness_run(int argc, char **argv)
 {
 	struct __fixture_variant_metadata no_variant = { .name = "", };
 	struct __fixture_variant_metadata *v;
 	struct __fixture_metadata *f;
 	struct __test_results *results;
 	struct __test_metadata *t;
-	int ret = 0;
+	int ret;
 	unsigned int case_count = 0, test_count = 0;
 	unsigned int count = 0;
 	unsigned int pass_count = 0;
 
+	ret = test_harness_argv_check(argc, argv);
+	if (ret != KSFT_PASS)
+		return ret;
+
 	for (f = __fixture_list; f; f = f->next) {
 		for (v = f->variant ?: &no_variant; v; v = v->next) {
-			case_count++;
+			unsigned int old_tests = test_count;
+
 			for (t = f->tests; t; t = t->next)
-				test_count++;
+				if (test_enabled(argc, argv, f, v, t))
+					test_count++;
+
+			if (old_tests != test_count)
+				case_count++;
 		}
 	}
 
@@ -1063,6 +1193,8 @@ static int test_harness_run(int __attribute__((unused)) argc,
 	for (f = __fixture_list; f; f = f->next) {
 		for (v = f->variant ?: &no_variant; v; v = v->next) {
 			for (t = f->tests; t; t = t->next) {
+				if (!test_enabled(argc, argv, f, v, t))
+					continue;
 				count++;
 				t->results = results;
 				__run_test(f, v, t);