Fix real pin tests ... and some other bits

The real pin tests were broken by the new factory stuff. This commit
fixes them up, and fixes up a few other bits besides (like why the
pigpio PWM tests were failing, why RPi.GPIO sometimes segfaulted on PWM
tests, etc.)

It also causes the real pin tests to run against MockPin (thanks to
@lurch for the suggestion!). This required some tweaks to MockPin to
make it emulate physically pulled up pins itself (which in turn
necessitated changing quite a few pin numbers in the main test suite
because we were using 2 and 3 everywhere), and to allow one MockPin to
drive another. Anyway, everything's working now including all the tests
on a Pi (haven't tried RPIO yet, but only because I'm on a Pi3 -
everything else works with overall coverage of 88% :).

tests/test_mock_pin.py

@@ -28,7 +28,7 @@ def test_mock_pin_init():
     assert Device._pin_factory.pin(2).number == 2
 
 def test_mock_pin_defaults():
-    pin = Device._pin_factory.pin(2)
+    pin = Device._pin_factory.pin(4)
     assert pin.bounce == None
     assert pin.edges == 'both'
     assert pin.frequency == None
@@ -36,6 +36,9 @@ def test_mock_pin_defaults():
     assert pin.pull == 'floating'
     assert pin.state == 0
     assert pin.when_changed == None
+    pin.close()
+    pin = Device._pin_factory.pin(2)
+    assert pin.pull == 'up'
 
 def test_mock_pin_open_close():
     pin = Device._pin_factory.pin(2)
@@ -54,7 +57,7 @@ def test_mock_pin_init_twice_different_pin():
     assert pin2.number == pin1.number+1
 
 def test_mock_pwm_pin_defaults():
-    pin = Device._pin_factory.pin(2, pin_class=MockPWMPin)
+    pin = Device._pin_factory.pin(4, pin_class=MockPWMPin)
     assert pin.bounce == None
     assert pin.edges == 'both'
     assert pin.frequency == None
@@ -62,6 +65,9 @@ def test_mock_pwm_pin_defaults():
     assert pin.pull == 'floating'
     assert pin.state == 0
     assert pin.when_changed == None
+    pin.close()
+    pin = Device._pin_factory.pin(2, pin_class=MockPWMPin)
+    assert pin.pull == 'up'
 
 def test_mock_pwm_pin_open_close():
     pin = Device._pin_factory.pin(2, pin_class=MockPWMPin)
@@ -104,20 +110,25 @@ def test_mock_pin_frequency_supported():
     assert not pin.state
 
 def test_mock_pin_pull():
-    pin = Device._pin_factory.pin(2)
+    pin = Device._pin_factory.pin(4)
     pin.function = 'input'
     assert pin.pull == 'floating'
     pin.pull = 'up'
     assert pin.state
     pin.pull = 'down'
     assert not pin.state
+    pin.close()
+    pin = Device._pin_factory.pin(2)
+    pin.function = 'input'
+    assert pin.pull == 'up'
+    with pytest.raises(PinFixedPull):
+        pin.pull = 'floating'
 
 def test_mock_pin_state():
     pin = Device._pin_factory.pin(2)
     with pytest.raises(PinSetInput):
         pin.state = 1
     pin.function = 'output'
-    assert pin.state == 0
     pin.state = 1
     assert pin.state == 1
     pin.state = 0
@@ -130,7 +141,6 @@ def test_mock_pwm_pin_state():
     with pytest.raises(PinSetInput):
         pin.state = 1
     pin.function = 'output'
-    assert pin.state == 0
     pin.state = 1
     assert pin.state == 1
     pin.state = 0