tests: kernel: cycle64: mark test as slow

Previously cycle64 was under `samples/`. It's been moved to
`tests/` and has been marked with `slow: True` so that it
will not disrupt CI by adding excessive delays.

Fixes #40367

Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>

samples/kernel/cycle64/prj.conf

@@ -1,3 +0,0 @@
-CONFIG_TEST=y
-CONFIG_PRINTK=y
-CONFIG_ASSERT=y

samples/kernel/cycle64/sample.yaml

@@ -1,17 +0,0 @@
-sample:
-  description: k_cycle_get_64() example
-  name: cycle64
-common:
-  integration_platforms:
-    - native_posix_64
-    - qemu_riscv
-    - qemu_riscv64
-  tags: kernel
-  harness: console
-  harness_config:
-    type: one_line
-    regex:
-      - "SUCCESS"
-tests:
-    sample.kernel.cycle64:
-        filter: CONFIG_TIMER_HAS_64BIT_CYCLE_COUNTER

tests/kernel/timer/cycle64/prj.conf

@@ -0,0 +1,2 @@
+CONFIG_ZTEST=y
+CONFIG_PRINTK=y

tests/kernel/timer/cycle64/src/main.c

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <ztest.h>
 #include <zephyr.h>
 
 static void swap64(uint64_t *a, uint64_t *b)
@@ -41,7 +42,7 @@ uint32_t timeout(uint64_t prev, uint64_t now)
 	return (uint32_t)next;
 }
 
-void main(void)
+static void test_32bit_wrap_around(void)
 {
 	enum {
 		CURR,
@@ -52,7 +53,7 @@ void main(void)
 	uint64_t now;
 	uint64_t c64[2];
 
-	printk("wrap-around should occur in %us\n",
+	printk("32-bit wrap-around should occur every %us\n",
 	       (uint32_t)(BIT64(32) / (uint32_t)sys_clock_hw_cycles_per_sec()));
 
 	printk("[ddd:hh:mm:ss.0ms]\n");
@@ -60,7 +61,7 @@ void main(void)
 	c64[CURR] = k_cycle_get_64();
 	msg(c64[CURR]);
 
-	for (i = 0; i < 3; ++i) {
+	for (i = 0; i < 2; ++i) {
 		k_sleep(Z_TIMEOUT_CYC(timeout(c64[CURR], k_cycle_get_64())));
 
 		now = k_cycle_get_64();
@@ -69,9 +70,15 @@ void main(void)
 
 		msg(c64[CURR]);
 
-		__ASSERT(((c64[CURR] - c64[PREV]) >> 32) == 1,
-			 "The 64-bit cycle counter did not increment!");
+		zassert_equal(((c64[CURR] - c64[PREV]) >> 32), 1,
+			 "The 64-bit cycle counter did not increment by 2^32");
 	}
-
-	printk("SUCCESS\n");
+}
+
+void test_main(void)
+{
+	ztest_test_suite(cycle64_tests,
+			 ztest_unit_test(test_32bit_wrap_around));
+
+	ztest_run_test_suite(cycle64_tests);
 }

tests/kernel/timer/cycle64/testcase.yaml

@@ -0,0 +1,22 @@
+# Note: Re: slow vs fast
+#
+# Some platforms such as native_posix, qemu_riscv32, qemu_riscv64
+# complete these tests almost instantaneously because of qemu timer
+# quirks ("time warp") even though the test reports that it completes
+# in e.g. 14 s. We can take advantage of that for fast tests on each PR
+# but we also want to excercise this code path during daily builds or
+# otherwise when users specify "twister --enable-slow".
+#
+# As other platforms are added with varying timer frequencies, increase
+# timeout as necessary.
+tests:
+  kernel.timer.cycle64:
+    tags: kernel timer
+    filter: CONFIG_TIMER_HAS_64BIT_CYCLE_COUNTER
+    platform_exclude: native_posix
+    timeout: 140
+    slow: true
+  kernel.timer.cycle64.fast:
+    tags: kernel timer
+    filter: CONFIG_TIMER_HAS_64BIT_CYCLE_COUNTER
+    platform_allow: native_posix