HAL sleep test fix

Prevents ticker upper layer initialization during test execution

Author: maciejbocianski

TESTS/mbed_hal/sleep/main.cpp

@@ -105,6 +105,11 @@ void sleep_usticker_test()
 
     const ticker_irq_handler_type us_ticker_irq_handler_org = set_us_ticker_irq_handler(us_ticker_isr);
 
+    // call ticker_read_us to initialize ticker upper layer
+    // prevents subsequent scheduling of max_delta interrupt during ticker initialization while test execution
+    // (e.g when ticker_read_us is called)
+    ticker_read_us(ticker);
+
     /* Test only sleep functionality. */
     sleep_manager_lock_deep_sleep();
     TEST_ASSERT_FALSE_MESSAGE(sleep_manager_can_deep_sleep(), "deep sleep should be locked");
@@ -143,6 +148,11 @@ void deepsleep_lpticker_test()
     const unsigned int ticker_freq = ticker->interface->get_info()->frequency;
     const unsigned int ticker_width = ticker->interface->get_info()->bits;
 
+    // call ticker_read_us to initialize ticker upper layer
+    // prevents subsequent scheduling of max_delta interrupt during ticker initialization while test execution
+    // (e.g when ticker_read_us is called)
+    ticker_read_us(ticker);
+
     const ticker_irq_handler_type lp_ticker_irq_handler_org = set_lp_ticker_irq_handler(lp_ticker_isr);
 
     /* Give some time Green Tea to finish UART transmission before entering