test: Support tests which can only be run manually

At present we normally write tests either in Python or in C. But most
Python tests end up doing a lot of checks which would be better done in C.
Checks done in C are orders of magnitude faster and it is possible to get
full access to U-Boot's internal workings, rather than just relying on
the command line.

The model is to have a Python test set up some things and then use C code
(in a unit test) to check that they were done correctly. But we don't want
those checks to happen as part of normal test running, since each C unit
tests is dependent on the associate Python tests, so cannot run without
it.

To acheive this, add a new UT_TESTF_MANUAL flag to use with the C 'check'
tests, so that they can be skipped by default when the 'ut' command is
used. Require that tests have a name ending with '_norun', so that pytest
knows to skip them.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/cpu/spl.c

@@ -89,7 +89,7 @@ void spl_board_init(void)
 		int ret;
 
 		ret = ut_run_list("spl", NULL, tests, count,
-				  state->select_unittests, 1);
+				  state->select_unittests, 1, false);
 		/* continue execution into U-Boot */
 	}
 }

doc/develop/tests_writing.rst

@@ -74,6 +74,33 @@ NOT rely on running with sandbox, but instead should function correctly on any
 board supported by U-Boot.
 
 
+Mixing Python and C
+-------------------
+
+The best of both worlds is sometimes to have a Python test set things up and
+perform some operations, with a 'checker' C unit test doing the checks
+afterwards. This can be achieved with these steps:
+
+- Add the `UT_TESTF_MANUAL` flag to the checker test so that the `ut` command
+  does not run it by default
+- Add a `_norun` suffix to the name so that pytest knows to skip it too
+
+In your Python test use the `-f` flag to the `ut` command to force the checker
+test to run it, e.g.::
+
+   # Do the Python part
+   host load ...
+   bootm ...
+
+   # Run the checker to make sure that everything worked
+   ut -f bootstd vbe_test_fixup_norun
+
+Note that apart from the `UT_TESTF_MANUAL` flag, the code in a 'manual' C test
+is just like any other C test. It still uses ut_assert...() and other such
+constructs, in this case to check that the expected things happened in the
+Python test.
+
+
 How slow are Python tests?
 --------------------------
 

include/test/test.h

@@ -28,6 +28,7 @@
  * @other_fdt_size: Size of the other FDT (UT_TESTF_OTHER_FDT)
  * @of_other: Live tree for the other FDT
  * @runs_per_test: Number of times to run each test (typically 1)
+ * @force_run: true to run tests marked with the UT_TESTF_MANUAL flag
  * @expect_str: Temporary string used to hold expected string value
  * @actual_str: Temporary string used to hold actual string value
  */
@@ -48,6 +49,7 @@ struct unit_test_state {
 	int other_fdt_size;
 	struct device_node *of_other;
 	int runs_per_test;
+	bool force_run;
 	char expect_str[512];
 	char actual_str[512];
 };
@@ -63,6 +65,12 @@ enum {
 	/* do extra driver model init and uninit */
 	UT_TESTF_DM		= BIT(6),
 	UT_TESTF_OTHER_FDT	= BIT(7),	/* read in other device tree */
+	/*
+	 * Only run if explicitly requested with 'ut -f <suite> <test>'. The
+	 * test name must end in "_norun" so that pytest detects this also,
+	 * since it cannot access the flags.
+	 */
+	UT_TESTF_MANUAL		= BIT(8),
 };
 
 /**

include/test/ut.h

@@ -409,9 +409,11 @@ void test_set_state(struct unit_test_state *uts);
  * @select_name: Name of a single test to run (from the list provided). If NULL
  *	then all tests are run
  * @runs_per_test: Number of times to run each test (typically 1)
+ * @force_run: Run tests that are marked as manual-only (UT_TESTF_MANUAL)
  * Return: 0 if all tests passed, -1 if any failed
  */
 int ut_run_list(const char *name, const char *prefix, struct unit_test *tests,
-		int count, const char *select_name, int runs_per_test);
+		int count, const char *select_name, int runs_per_test,
+		bool force_run);
 
 #endif

test/cmd_ut.c

@@ -19,16 +19,26 @@ int cmd_ut_category(const char *name, const char *prefix,
 		    int argc, char *const argv[])
 {
 	int runs_per_text = 1;
+	bool force_run = false;
 	int ret;
 
-	if (argc > 1 && !strncmp("-r", argv[1], 2)) {
-		runs_per_text = dectoul(argv[1] + 2, NULL);
+	while (argc > 1 && *argv[1] == '-') {
+		const char *str = argv[1];
+
+		switch (str[1]) {
+		case 'r':
+			runs_per_text = dectoul(str + 2, NULL);
+			break;
+		case 'f':
+			force_run = true;
+			break;
+		}
 		argv++;
 		argc++;
 	}
 
 	ret = ut_run_list(name, prefix, tests, n_ents,
-			  argc > 1 ? argv[1] : NULL, runs_per_text);
+			  argc > 1 ? argv[1] : NULL, runs_per_text, force_run);
 
 	return ret ? CMD_RET_FAILURE : 0;
 }

test/dm/test-dm.c

@@ -36,7 +36,7 @@ static int dm_test_run(const char *test_name, int runs_per_text)
 	int ret;
 
 	ret = ut_run_list("driver model", "dm_test_", tests, n_ents, test_name,
-			  runs_per_text);
+			  runs_per_text, false);
 
 	return ret ? CMD_RET_FAILURE : 0;
 }

test/py/conftest.py

@@ -289,7 +289,13 @@ def generate_ut_subtest(metafunc, fixture_name, sym_path):
         m = re_ut_test_list.search(l)
         if not m:
             continue
-        vals.append(m.group(1) + ' ' + m.group(2))
+        suite, name = m.groups()
+
+        # Tests marked with _norun should only be run manually using 'ut -f'
+        if name.endswith('_norun'):
+            continue
+
+        vals.append(f'{suite} {name}')
 
     ids = ['ut_' + s.replace(' ', '_') for s in vals]
     metafunc.parametrize(fixture_name, vals, ids=ids)

test/test-main.c

@@ -508,6 +508,30 @@ static int ut_run_tests(struct unit_test_state *uts, const char *prefix,
 
 		if (!test_matches(prefix, test_name, select_name))
 			continue;
+
+		if (test->flags & UT_TESTF_MANUAL) {
+			int len;
+
+			/*
+			 * manual tests must have a name ending "_norun" as this
+			 * is how pytest knows to skip them. See
+			 * generate_ut_subtest() for this check.
+			 */
+			len = strlen(test_name);
+			if (len < 6 || strcmp(test_name + len - 6, "_norun")) {
+				printf("Test %s is manual so must have a name ending in _norun\n",
+				       test_name);
+				uts->fail_count++;
+				return -EBADF;
+			}
+			if (!uts->force_run) {
+				if (select_name) {
+					printf("Test %s skipped as it is manual (use -f to run it)\n",
+					       test_name);
+				}
+				continue;
+			}
+		}
 		old_fail_count = uts->fail_count;
 		for (i = 0; i < uts->runs_per_test; i++)
 			ret = ut_run_test_live_flat(uts, test, select_name);
@@ -529,7 +553,7 @@ static int ut_run_tests(struct unit_test_state *uts, const char *prefix,
 
 int ut_run_list(const char *category, const char *prefix,
 		struct unit_test *tests, int count, const char *select_name,
-		int runs_per_test)
+		int runs_per_test, bool force_run)
 {
 	struct unit_test_state uts = { .fail_count = 0 };
 	bool has_dm_tests = false;
@@ -563,6 +587,7 @@ int ut_run_list(const char *category, const char *prefix,
 		}
 		memcpy(uts.fdt_copy, gd->fdt_blob, uts.fdt_size);
 	}
+	uts.force_run = force_run;
 	ret = ut_run_tests(&uts, prefix, tests, count, select_name);
 
 	/* Best efforts only...ignore errors */