initial commit of test_blynclight_hid.py

Author: JnyJny

tests/test_blynclight_hid.py

@@ -0,0 +1,125 @@
+"""Test blynclight.hid.HidDevice
+
+These tests do not depend on the existence of a particular
+USB device but it does require *some* USB devices to act
+upon.
+
+These tests focus on enumerating, opening, and closing
+devices. The read and write functions are not tested
+since that requires some specific knowledge about the
+device we are attempting to perform I/O on.
+
+"""
+
+import pytest
+from blynclight.hid import HidDevice
+
+
+@pytest.fixture(scope="session")
+def devices():
+    """List of dictionaries fixture returned from the class method
+    blynclight.hid.HidDevice.enumerate(). The enumerate method makes
+    no guarantees about device ordering between invocations, so we use
+    session scope for this fixture to keep repeated uses consistent
+    between tests.
+
+    """
+    return HidDevice.enumerate()
+
+
+@pytest.fixture(scope="session")
+def hid_device(devices):
+    """A blynclight.hid.HidDevice fixture that represents the last device
+    in the 'devices' fixture. Tests often use the first device in
+    devices so using the last device avoids attempting to open a
+    device that is already open while still making a HidDevice
+    available. This fixture has session scope.
+
+    """
+    device = HidDevice.from_dict(devices[-1])
+    yield device
+
+
+def test_classmethod_enumerate():
+    """Ensure that the output of blynclight.hid.HidDevice.enumerate
+    returns a list of dictionaries and spot checks the dictionary
+    contents for the keys 'vendor_id' and 'product_id'.
+
+    """
+    devices = HidDevice.enumerate()
+    assert devices
+    assert isinstance(devices, list)
+
+    for device in devices:
+        assert device
+        assert isinstance(device, dict)
+        assert "vendor_id" in device.keys()
+        assert "product_id" in device.keys()
+
+
+def test_classmethod_from_dict_good_data(devices):
+    """:param devices: list of dictionaries fixture
+
+    Tests the blynclight.hid.HidDevice.from_dict convenience method
+    using presumably good device information dictionaries sourced from
+    the enumerate class method.
+
+    """
+    try:
+        device = HidDevice.from_dict(devices[0])
+        assert isinstance(device, HidDevice)
+        assert device.vendor_id == devices[0]["vendor_id"]
+        assert device.product_id == devices[0]["product_id"]
+        del (device)
+    except KeyError:
+        pass
+
+
+def test_classmethod_from_dict_bad_data():
+    """Tests the blynclight.hid.HidDevice.from_dict convenience method
+    using synthetic bad data, specifically:
+
+    - an empty dictionary
+    - a dictionary with only a vendor_id key
+    - a dictionary with only a product_id key
+
+    """
+
+    with pytest.raises(LookupError):
+        HidDevice.from_dict({})
+
+    with pytest.raises(LookupError):
+        HidDevice.from_dict({"vendor_id": None})
+
+    with pytest.raises(LookupError):
+        HidDevice.from_dict({"product_id": None})
+
+
+def test_hiddevice_init(devices):
+    """:param devices: list of dictionaries fixture
+
+    Tests creating a blynclight.hid.HidDevice and ensures that the
+    HidDevice is configured with the specified vendor_id and
+    product_id.
+
+    """
+
+    device = HidDevice(devices[0]["vendor_id"], devices[0]["product_id"])
+    assert isinstance(device, HidDevice)
+    assert device.vendor_id == devices[0]["vendor_id"]
+    assert device.product_id == devices[0]["product_id"]
+
+
+def test_hiddevice_open_twice(devices):
+    """:param devices: list of dictionaries fixture
+
+    The hidapi library does not allow a USB device to be opened twice
+    in the same process, so we test for that by opening the first
+    device twice.
+
+    """
+
+    device = HidDevice.from_dict(devices[0])
+
+    with pytest.raises(ValueError):
+        HidDevice(device.vendor_id, device.product_id)