Work on #87

Implement a test suite, including Travis-CI integration

tests/test_mock_pin.py

@@ -0,0 +1,74 @@
+from __future__ import (
+    unicode_literals,
+    absolute_import,
+    print_function,
+    division,
+    )
+str = type('')
+
+
+from threading import Event
+
+import pytest
+
+from gpiozero.pins.mock import MockPin, MockPWMPin
+from gpiozero import *
+
+
+# Some rough tests to make sure our MockPin is up to snuff. This is just
+# enough to get reasonable coverage but it's by no means comprehensive...
+
+def test_mock_pin_init():
+    with pytest.raises(ValueError):
+        MockPin(60)
+    assert MockPin(2).number == 2
+
+def test_mock_pin_frequency_unsupported():
+    with pytest.raises(AttributeError):
+        pin = MockPin(3)
+        pin.frequency = 100
+
+def test_mock_pin_frequency_supported():
+    pin = MockPWMPin(3)
+    pin.function = 'output'
+    assert pin.frequency is None
+    pin.frequency = 100
+    pin.state = 0.5
+    pin.frequency = None
+    assert not pin.state
+
+def test_mock_pin_pull():
+    pin = MockPin(4)
+    pin.function = 'input'
+    assert pin.pull == 'floating'
+    pin.pull = 'up'
+    assert pin.state
+    pin.pull = 'down'
+    assert not pin.state
+
+def test_mock_pin_edges():
+    pin = MockPin(5)
+    assert pin.when_changed is None
+    fired = Event()
+    pin.function = 'input'
+    pin.edges = 'both'
+    assert pin.edges == 'both'
+    pin.drive_low()
+    assert not pin.state
+    def changed():
+        fired.set()
+    pin.when_changed = changed
+    pin.drive_high()
+    assert pin.state
+    assert fired.wait(0)
+    fired.clear()
+    pin.edges = 'falling'
+    pin.drive_low()
+    assert not pin.state
+    assert fired.wait(0)
+    fired.clear()
+    pin.drive_high()
+    assert pin.state
+    assert not fired.wait(0)
+    assert pin.edges == 'falling'
+