Fix #204 and start readying the release

Also re-numbers energenie sockets 1-4 (as noted by @bennuttall in
comments to #239), and adds several "real pins" tests and board tests.
The bad-PWM stuff is currently disabled as it causes segfaults when
running the tests and I can't seem to trace the cause at the moment.
Finally, I've tweaked the deb config to suggest gpiozero, removed spidev
as a mandatory dep (which'll fix installs on wheezy for py3), and
there's some more miscellaneous last-minute stuff here that I can't
recall...

tests/test_real_pins.py

@@ -5,7 +5,10 @@ from __future__ import (
     division,
     )
 str = type('')
-
+try:
+    range = xrange
+except NameError:
+    pass
 
 import io
 import subprocess
@@ -13,6 +16,10 @@ import subprocess
 import pytest
 
 from gpiozero import PinFixedPull, PinInvalidPull, PinInvalidFunction
+try:
+    from math import isclose
+except ImportError:
+    from gpiozero.compat import isclose
 
 
 # This module assumes you've wired the following GPIO pins together
@@ -56,7 +63,6 @@ try:
 except ImportError:
     NativePin = None
 
-
 @pytest.fixture(scope='module', params=PIN_CLASSES)
 def pin_class(request):
     # pigpiod needs to be running for PiGPIOPin
@@ -70,13 +76,13 @@ def pin_class(request):
         request.addfinalizer(kill_pigpiod)
     return request.param
 
-@pytest.fixture
+@pytest.fixture(scope='function')
 def pins(request, pin_class):
     # Why return both pins in a single fixture? If we defined one fixture for
     # each pin then pytest will (correctly) test RPiGPIOPin(22) against
     # NativePin(27) and so on. This isn't supported, so we don't test it
-    test_pin = pin_class(22)
-    input_pin = pin_class(27)
+    test_pin = pin_class(TEST_PIN)
+    input_pin = pin_class(INPUT_PIN)
     input_pin.function = 'input'
     input_pin.pull = 'down'
     def fin():
@@ -88,8 +94,8 @@ def pins(request, pin_class):
 
 def test_pin_numbers(pins):
     test_pin, input_pin = pins
-    assert test_pin.number == 22
-    assert input_pin.number == 27
+    assert test_pin.number == TEST_PIN
+    assert input_pin.number == INPUT_PIN
 
 def test_function_bad(pins):
     test_pin, input_pin = pins
@@ -125,12 +131,18 @@ def test_pull_bad(pins):
     test_pin.function = 'input'
     with pytest.raises(PinInvalidPull):
         test_pin.pull = 'foo'
+    with pytest.raises(PinInvalidPull):
+        test_pin.input_with_pull('foo')
 
 def test_pull_down_warning(pin_class):
+    # XXX This assumes we're on a vaguely modern Pi and not a compute module
+    # Might want to refine this with the pi-info database
     pin = pin_class(2)
     try:
         with pytest.raises(PinFixedPull):
             pin.pull = 'down'
+        with pytest.raises(PinFixedPull):
+            pin.input_with_pull('down')
     finally:
         pin.close()
 
@@ -141,3 +153,25 @@ def test_input_with_pull(pins):
     test_pin.input_with_pull('down')
     assert input_pin.state == 0
 
+@pytest.mark.skipif(True, reason='causes segfaults')
+def test_bad_duty_cycle(pins):
+    test_pin, input_pin = pins
+    if test_pin.__class__.__name__ == 'NativePin':
+        pytest.skip("native pin doesn't support PWM")
+    test_pin.function = 'output'
+    test_pin.frequency = 100
+    with pytest.raises(ValueError):
+        test_pin.state = 1.1
+
+def test_duty_cycles(pins):
+    test_pin, input_pin = pins
+    if test_pin.__class__.__name__ == 'NativePin':
+        pytest.skip("native pin doesn't support PWM")
+    test_pin.function = 'output'
+    test_pin.frequency = 100
+    for duty_cycle in (0.0, 0.1, 0.5, 1.0):
+        test_pin.state = duty_cycle
+        assert test_pin.state == duty_cycle
+        total = sum(input_pin.state for i in range(20000))
+        assert isclose(total / 20000, duty_cycle, rel_tol=0.1, abs_tol=0.1)
+