tests/extmod: Add a simple test for machine.RTC.

Tests at least that the datetime can be set and get correctly.

Signed-off-by: Damien George <damien@micropython.org>

tests/extmod/machine_rtc.py

@@ -0,0 +1,24 @@
+# Test basic behaviour of machine.RTC.
+
+try:
+    from machine import RTC
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+rtc = machine.RTC()
+
+# Save datetime.
+orig_datetime = rtc.datetime()
+
+# Set datetime to a known value.
+rtc.datetime((2020, 1, 1, 0, 0, 0, 0, 0))
+
+# Check that getting and setting the datetime give expected values.
+for i in range(4):
+    now = rtc.datetime()
+    print(now[0], now[1], now[2], now[4], now[5])
+    rtc.datetime(now)
+
+# Restore datetime.
+rtc.datetime(orig_datetime)

tests/extmod/machine_rtc.py.exp

@@ -0,0 +1,4 @@
+2020 1 1 0 0
+2020 1 1 0 0
+2020 1 1 0 0
+2020 1 1 0 0