Expand test coverage and improve tests

library/tests/conftest.py

@@ -0,0 +1,101 @@
+import sys
+import mock
+import pytest
+import bme680
+from bme680.constants import CalibrationData
+
+
+class MockSMBus:
+    """Mock a basic non-presence SMBus device to cause BME680 to fail.
+
+    Returns 0 in all cases, so that CHIP_ID will never match.
+
+    """
+
+    def __init__(self, bus):  # noqa D107
+        pass
+
+    def read_byte_data(self, addr, register):
+        """Return 0 for all read attempts."""
+        return 0
+
+
+class MockSMBusPresent:
+    """Mock enough of the BME680 for the library to initialise and test."""
+
+    def __init__(self, bus):
+        """Initialise with test data."""
+        self.regs = [0 for _ in range(256)]
+        self.regs[bme680.CHIP_ID_ADDR] = bme680.CHIP_ID
+
+    def read_byte_data(self, addr, register):
+        """Read a single byte from fake registers."""
+        return self.regs[register]
+
+    def write_byte_data(self, addr, register, value):
+        """Write a single byte to fake registers."""
+        self.regs[register] = value
+
+    def read_i2c_block_data(self, addr, register, length):
+        """Read up to length bytes from register."""
+        return self.regs[register:register + length]
+
+
+@pytest.fixture(scope='function', autouse=False)
+def smbus_notpresent():
+    """Mock smbus module."""
+    smbus = mock.MagicMock()
+    smbus.SMBus = MockSMBus
+    sys.modules['smbus'] = smbus
+    yield smbus
+    del sys.modules['smbus']
+
+
+@pytest.fixture(scope='function', autouse=False)
+def smbus():
+    """Mock smbus module."""
+    smbus = mock.MagicMock()
+    smbus.SMBus = MockSMBusPresent
+    sys.modules['smbus'] = smbus
+    yield smbus
+    del sys.modules['smbus']
+
+
+@pytest.fixture(scope='function', autouse=False)
+def calibration():
+    """Mock bme680 calibration."""
+    calibration = CalibrationData()
+    # Dump of calibration data borrowed from:
+    # https://github.com/pimoroni/bme680-python/issues/11
+    data = {
+        'par_gh1': -30,
+        'par_gh2': -24754,
+        'par_gh3': 18,
+        'par_h1': 676,
+        'par_h2': 1029,
+        'par_h3': 0,
+        'par_h4': 45,
+        'par_h5': 20,
+        'par_h6': 120,
+        'par_h7': -100,
+        'par_p1': 36673,
+        'par_p10': 30,
+        'par_p2': -10515,
+        'par_p3': 88,
+        'par_p4': 7310,
+        'par_p5': -129,
+        'par_p6': 30,
+        'par_p7': 46,
+        'par_p8': -3177,
+        'par_p9': -2379,
+        'par_t1': 26041,
+        'par_t2': 26469,
+        'par_t3': 3,
+        'range_sw_err': 0,
+        'res_heat_range': 1,
+        'res_heat_val': 48,
+        't_fine': 136667
+    }
+    for k, v in data.items():
+        setattr(calibration, k, v)
+    return calibration