tests/extmod_hardware: Add basic tests for machine.Counter and Encoder.

These don't test any advanced features, just the basics.

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

tests/extmod_hardware/machine_counter.py

@@ -0,0 +1,90 @@
+# Test machine.Counter implementation
+#
+# IMPORTANT: This test requires hardware connections: the out_pin and in_pin
+# must be wired together.
+
+try:
+    from machine import Counter
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+import sys
+from machine import Pin
+
+if "esp32" in sys.platform:
+    id = 0
+    out_pin = 4
+    in_pin = 5
+else:
+    print("Please add support for this test on this platform.")
+    raise SystemExit
+
+import unittest
+
+out_pin = Pin(out_pin, mode=Pin.OUT)
+in_pin = Pin(in_pin, mode=Pin.IN)
+
+
+def toggle(times):
+    for _ in range(times):
+        out_pin(1)
+        out_pin(0)
+
+
+class TestCounter(unittest.TestCase):
+    def setUp(self):
+        out_pin(0)
+        self.counter = Counter(id, in_pin)
+
+    def tearDown(self):
+        self.counter.deinit()
+
+    def assertCounter(self, value):
+        self.assertEqual(self.counter.value(), value)
+
+    def test_connections(self):
+        # Test the hardware connections are correct. If this test fails, all tests will fail.
+        out_pin(1)
+        self.assertEqual(1, in_pin())
+        out_pin(0)
+        self.assertEqual(0, in_pin())
+
+    def test_count_rising(self):
+        self.assertCounter(0)
+        toggle(100)
+        self.assertCounter(100)
+        out_pin(1)
+        self.assertEqual(self.counter.value(0), 101)
+        self.assertCounter(0)  # calling value(0) resets
+        out_pin(0)
+        self.assertCounter(0)  # no rising edge
+        out_pin(1)
+        self.assertCounter(1)
+
+    def test_change_directions(self):
+        self.assertCounter(0)
+        toggle(100)
+        self.assertCounter(100)
+        self.counter.init(in_pin, direction=Counter.DOWN)
+        self.assertCounter(0)  # calling init() zeroes the counter
+        self.counter.value(100)  # need to manually reset the value
+        self.assertCounter(100)
+        toggle(25)
+        self.assertCounter(75)
+
+    def test_count_falling(self):
+        self.counter.init(in_pin, direction=Counter.UP, edge=Counter.FALLING)
+        toggle(20)
+        self.assertCounter(20)
+        out_pin(1)
+        self.assertCounter(20)  # no falling edge
+        out_pin(0)
+        self.assertCounter(21)
+        self.counter.value(-(2**24))
+        toggle(20)
+        self.assertCounter(-(2**24 - 20))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/extmod_hardware/machine_encoder.py

@@ -0,0 +1,99 @@
+# Test machine.Encoder implementation
+#
+# IMPORTANT: This test requires hardware connections:
+# - out0_pin and in0_pin must be wired together.
+# - out1_pin and in1_pin must be wired together.
+
+try:
+    from machine import Encoder
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+import sys
+from machine import Pin
+
+if "esp32" in sys.platform:
+    id = 0
+    out0_pin = 4
+    in0_pin = 5
+    out1_pin = 12
+    in1_pin = 13
+else:
+    print("Please add support for this test on this platform.")
+    raise SystemExit
+
+import unittest
+
+out0_pin = Pin(out0_pin, mode=Pin.OUT)
+in0_pin = Pin(in0_pin, mode=Pin.IN)
+out1_pin = Pin(out1_pin, mode=Pin.OUT)
+in1_pin = Pin(in1_pin, mode=Pin.IN)
+
+
+class TestEncoder(unittest.TestCase):
+    def setUp(self):
+        out0_pin(0)
+        out1_pin(0)
+        self.enc = Encoder(id, in0_pin, in1_pin)
+        self.pulses = 0  # track the expected encoder position in software
+
+    def tearDown(self):
+        self.enc.deinit()
+
+    def rotate(self, pulses):
+        for _ in range(abs(pulses)):
+            self.pulses += 1 if (pulses > 0) else -1
+            q = self.pulses % 4
+            # Only one pin should change state each "step" so output won't glitch
+            out0_pin(q in (1, 2))
+            out1_pin(q in (2, 3))
+
+    def assertPosition(self, value):
+        self.assertEqual(self.enc.value(), value)
+
+    def test_connections(self):
+        # Test the hardware connections are correct. If this test fails, all tests will fail.
+        for ch, outp, inp in ((0, out0_pin, in0_pin), (1, out1_pin, in1_pin)):
+            print("Testing channel ", ch)
+            outp(1)
+            self.assertEqual(1, inp())
+            outp(0)
+            self.assertEqual(0, inp())
+
+    def test_basics(self):
+        self.assertPosition(0)
+        self.rotate(100)
+        self.assertPosition(100 // 4)
+        self.rotate(-100)
+        self.assertPosition(0)
+
+    def test_partial(self):
+        # With phase=1 (default), need 4x pulses to count a rotation
+        self.assertPosition(0)
+        self.rotate(1)
+        self.assertPosition(0)
+        self.rotate(1)
+        self.assertPosition(0)
+        self.rotate(1)
+        self.assertPosition(1)  # only 3 pulses to count first rotation?
+        self.rotate(1)
+        self.assertPosition(1)
+        self.rotate(1)
+        self.assertPosition(1)
+        self.rotate(1)
+        self.assertPosition(1)
+        self.rotate(1)
+        self.assertPosition(2)  # 4 for next rotation
+        self.rotate(-1)
+        self.assertPosition(1)
+        self.rotate(-4)
+        self.assertPosition(0)
+        self.rotate(-4)
+        self.assertPosition(-1)
+        self.rotate(-3)
+        self.assertPosition(-1)
+
+
+if __name__ == "__main__":
+    unittest.main()