kunit: Print test statistics on failure

When a number of tests fail, it can be useful to get higher-level
statistics of how many tests are failing (or how many parameters are
failing in parameterised tests), and in what cases or suites. This is
already done by some non-KUnit tests, so add support for automatically
generating these for KUnit tests.

This change adds a 'kunit.stats_enabled' switch which has three values:
- 0: No stats are printed (current behaviour)
- 1: Stats are printed only for tests/suites with more than one
     subtest (new default)
- 2: Always print test statistics

For parameterised tests, the summary line looks as follows:
"    # inode_test_xtimestamp_decoding: pass:16 fail:0 skip:0 total:16"
For test suites, there are two lines looking like this:
"# ext4_inode_test: pass:1 fail:0 skip:0 total:1"
"# Totals: pass:16 fail:0 skip:0 total:16"

The first line gives the number of direct subtests, the second "Totals"
line is the accumulated sum of all tests and test parameters.

This format is based on the one used by kselftest[1].

[1]: https://elixir.bootlin.com/linux/latest/source/tools/testing/selftests/kselftest.h#L109

Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/lib/kunit/test.c b/lib/kunit/test.c
index d79ecb86ea57..f246b847024e 100644
--- a/lib/kunit/test.c
+++ b/lib/kunit/test.c
@@ -10,6 +10,7 @@
 #include <kunit/test-bug.h>
 #include <linux/kernel.h>
 #include <linux/kref.h>
+#include <linux/moduleparam.h>
 #include <linux/sched/debug.h>
 #include <linux/sched.h>
 
@@ -52,6 +53,51 @@ EXPORT_SYMBOL_GPL(__kunit_fail_current_test);
 #endif
 
 /*
+ * KUnit statistic mode:
+ * 0 - disabled
+ * 1 - only when there is more than one subtest
+ * 2 - enabled
+ */
+static int kunit_stats_enabled = 1;
+module_param_named(stats_enabled, kunit_stats_enabled, int, 0644);
+MODULE_PARM_DESC(stats_enabled,
+		  "Print test stats: never (0), only for multiple subtests (1), or always (2)");
+
+struct kunit_result_stats {
+	unsigned long passed;
+	unsigned long skipped;
+	unsigned long failed;
+	unsigned long total;
+};
+
+static bool kunit_should_print_stats(struct kunit_result_stats stats)
+{
+	if (kunit_stats_enabled == 0)
+		return false;
+
+	if (kunit_stats_enabled == 2)
+		return true;
+
+	return (stats.total > 1);
+}
+
+static void kunit_print_test_stats(struct kunit *test,
+				   struct kunit_result_stats stats)
+{
+	if (!kunit_should_print_stats(stats))
+		return;
+
+	kunit_log(KERN_INFO, test,
+		  KUNIT_SUBTEST_INDENT
+		  "# %s: pass:%lu fail:%lu skip:%lu total:%lu",
+		  test->name,
+		  stats.passed,
+		  stats.failed,
+		  stats.skipped,
+		  stats.total);
+}
+
+/*
  * Append formatted message to log, size of which is limited to
  * KUNIT_LOG_SIZE bytes (including null terminating byte).
  */
@@ -393,15 +439,69 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
 		test_case->status = KUNIT_SUCCESS;
 }
 
+static void kunit_print_suite_stats(struct kunit_suite *suite,
+				    struct kunit_result_stats suite_stats,
+				    struct kunit_result_stats param_stats)
+{
+	if (kunit_should_print_stats(suite_stats)) {
+		kunit_log(KERN_INFO, suite,
+			  "# %s: pass:%lu fail:%lu skip:%lu total:%lu",
+			  suite->name,
+			  suite_stats.passed,
+			  suite_stats.failed,
+			  suite_stats.skipped,
+			  suite_stats.total);
+	}
+
+	if (kunit_should_print_stats(param_stats)) {
+		kunit_log(KERN_INFO, suite,
+			  "# Totals: pass:%lu fail:%lu skip:%lu total:%lu",
+			  param_stats.passed,
+			  param_stats.failed,
+			  param_stats.skipped,
+			  param_stats.total);
+	}
+}
+
+static void kunit_update_stats(struct kunit_result_stats *stats,
+			       enum kunit_status status)
+{
+	switch (status) {
+	case KUNIT_SUCCESS:
+		stats->passed++;
+		break;
+	case KUNIT_SKIPPED:
+		stats->skipped++;
+		break;
+	case KUNIT_FAILURE:
+		stats->failed++;
+		break;
+	}
+
+	stats->total++;
+}
+
+static void kunit_accumulate_stats(struct kunit_result_stats *total,
+				   struct kunit_result_stats add)
+{
+	total->passed += add.passed;
+	total->skipped += add.skipped;
+	total->failed += add.failed;
+	total->total += add.total;
+}
+
 int kunit_run_tests(struct kunit_suite *suite)
 {
 	char param_desc[KUNIT_PARAM_DESC_SIZE];
 	struct kunit_case *test_case;
+	struct kunit_result_stats suite_stats = { 0 };
+	struct kunit_result_stats total_stats = { 0 };
 
 	kunit_print_subtest_start(suite);
 
 	kunit_suite_for_each_test_case(suite, test_case) {
 		struct kunit test = { .param_value = NULL, .param_index = 0 };
+		struct kunit_result_stats param_stats = { 0 };
 		test_case->status = KUNIT_SKIPPED;
 
 		if (test_case->generate_params) {
@@ -431,14 +531,23 @@ int kunit_run_tests(struct kunit_suite *suite)
 				test.param_value = test_case->generate_params(test.param_value, param_desc);
 				test.param_index++;
 			}
+
+			kunit_update_stats(&param_stats, test.status);
+
 		} while (test.param_value);
 
+		kunit_print_test_stats(&test, param_stats);
+
 		kunit_print_ok_not_ok(&test, true, test_case->status,
 				      kunit_test_case_num(suite, test_case),
 				      test_case->name,
 				      test.status_comment);
+
+		kunit_update_stats(&suite_stats, test_case->status);
+		kunit_accumulate_stats(&total_stats, param_stats);
 	}
 
+	kunit_print_suite_stats(suite, suite_stats, total_stats);
 	kunit_print_subtest_end(suite);
 
 	return 0;