tests: ztest: Add test for busy simulator

Added test that validates busy simulator.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>

tests/ztest/busy_sim/CMakeLists.txt

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.13.1)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(uart_basic_api)
+
+target_sources(app PRIVATE
+    src/main.c
+    )

tests/ztest/busy_sim/boards/nrf52840dk_nrf52840.conf

@@ -0,0 +1 @@
+CONFIG_COUNTER_TIMER0=y

tests/ztest/busy_sim/boards/nrf52840dk_nrf52840.overlay

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+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&timer0 {
+	status = "okay";
+	interrupts = <8 0>;
+};
+
+/ {
+	busy-sim {
+		compatible = "vnd,busy-sim";
+		status = "okay";
+		counter = <&timer0>;
+	};
+};

tests/ztest/busy_sim/boards/nrf52840dk_nrf52840_pin.overlay

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&timer0 {
+	status = "okay";
+	interrupts = <8 0>;
+};
+
+/ {
+	busy-sim {
+		compatible = "vnd,busy-sim";
+		status = "okay";
+		counter = <&timer0>;
+		active-gpios = <&gpio0 27 GPIO_ACTIVE_HIGH>;
+	};
+};

tests/ztest/busy_sim/prj.conf

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+CONFIG_ZTEST=y
+CONFIG_TEST_BUSY_SIM=y
+CONFIG_ZTEST_THREAD_PRIORITY=1

tests/ztest/busy_sim/src/main.c

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+/*
+ * Copyright (c) 2021 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <ztest.h>
+#include <busy_sim.h>
+
+static void test_busy_sim(void)
+{
+	uint32_t ms = 1000;
+	uint32_t delta = 80;
+	uint32_t busy_ms;
+	uint32_t t = k_uptime_get_32();
+
+	k_busy_wait(1000 * ms);
+	t = k_uptime_get_32() - t;
+
+	zassert_true((t > (ms - delta)) && (t < (ms + delta)), NULL);
+
+	/* Start busy simulator and check that k_busy_wait last longer */
+	t = k_uptime_get_32();
+	busy_sim_start(500, 200, 1000, 400);
+	k_busy_wait(1000 * ms);
+	t = k_uptime_get_32() - t;
+	busy_ms = (3 * ms) / 2;
+
+	busy_sim_stop();
+	/* due to clock imprecision, randomness and addtional cpu load overhead
+	 * expected time range is increased.
+	 */
+	zassert_true((t > (busy_ms - 2 * delta)) && (t < (busy_ms + 4 * delta)),
+			"expected in range: %d-%d, k_busy_wait lasted %d",
+			busy_ms - 2 * delta, busy_ms + 4 * delta,  t);
+
+	/* Check that k_busy_wait is not interrupted after busy_sim_stop. */
+	t = k_uptime_get_32();
+	k_busy_wait(1000 * ms);
+	t = k_uptime_get_32() - t;
+	zassert_true((t > (ms - delta)) && (t < (ms + delta)), NULL);
+}
+
+void test_main(void)
+{
+	ztest_test_suite(busy_sim_tests,
+			 ztest_unit_test(test_busy_sim)
+			 );
+
+	ztest_run_test_suite(busy_sim_tests);
+}

tests/ztest/busy_sim/testcase.yaml

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+common:
+  tags: test_framework
+  depends_on: counter
+tests:
+  testing.ztest.busy_sim:
+    platform_allow: nrf52840dk_nrf52840
+  testing.ztest.busy_sim_nrf52840dk_pin:
+    platform_allow: nrf52840dk_nrf52840
+    extra_args: DTC_OVERLAY_FILE=boards/nrf52840dk_nrf52840_pin.overlay