Add CI testing

Author: zx100x100

.github/workflows/test.yml

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+name: Test
+
+on: ["pull_request", "push"]
+
+jobs:
+  Test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
+    steps:
+    - uses: actions/checkout@v4
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v5
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install pytest
+        pip install -e .
+
+    - name: Run tests
+      run: pytest -v

.gitignore

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+# Byte-compiled / optimized files
+__pycache__/
+*.py[cod]
+
+# Test / tooling caches
+.pytest_cache/
+
+# Packaging artifacts
+build/
+dist/
+*.egg-info/

conftest.py

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+"""Shared pytest fixtures.
+
+The tests run without hardware by substituting a fake ``smbus`` module for the
+real one. The fake is injected into ``sys.modules`` here, before ``tmp119`` is
+imported anywhere, so the library's top-level ``import smbus`` resolves to this
+in-memory stand-in instead of a physical I2C bus.
+"""
+
+import sys
+import types
+
+import pytest
+
+
+class FakeSMBus:
+    """In-memory stand-in for ``smbus.SMBus`` used for hardware-free testing.
+
+    Registers are stored big-endian as ``[msb, lsb]``, matching how the TMP119
+    transfers its 16-bit registers over I2C. Tests can read/modify ``regs`` to
+    simulate device state.
+    """
+
+    def __init__(self, bus):
+        self.bus = bus
+        self.regs = {
+            0x00: [0x00, 0x00],  # TEMP
+            0x01: [0x02, 0x20],  # CONFIG (power-on default 0x0220)
+            0x0F: [0x21, 0x17],  # DEVICE_ID (0x2117)
+        }
+
+    def read_i2c_block_data(self, address, register, length):
+        return list(self.regs[register])[:length]
+
+    def write_i2c_block_data(self, address, register, data):
+        self.regs[register] = list(data)
+
+
+_fake_smbus = types.ModuleType("smbus")
+_fake_smbus.SMBus = FakeSMBus
+sys.modules["smbus"] = _fake_smbus
+
+
+@pytest.fixture
+def sensor():
+    """A TMP119 backed by a fresh in-memory FakeSMBus."""
+    import tmp119
+    return tmp119.TMP119()

tests/test_tmp119.py

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+import pytest
+
+import tmp119
+
+# Config register bit masks (mirrors the private constants in the driver)
+AVG_MASK = 0x0060
+CONV_MASK = 0x0380
+
+
+def test_device_id(sensor):
+    assert sensor.get_device_id() == 0x2117
+
+
+def test_init_success_clears_avg_and_conv(sensor):
+    assert sensor.init() is True
+    assert sensor.get_config() & (AVG_MASK | CONV_MASK) == 0
+
+
+def test_init_preserves_unrelated_config_bits(sensor):
+    # Set a bit outside the AVG/CONV masks; init() must leave it untouched.
+    sensor._bus.regs[0x01] = [0x82, 0x20]  # 0x8220
+    assert sensor.init() is True
+    assert sensor.get_config() == 0x8000
+
+
+def test_init_fails_on_wrong_device_id(sensor):
+    sensor._bus.regs[0x0F] = [0x00, 0x00]
+    assert sensor.init() is False
+
+
+def test_init_returns_false_without_bus(sensor):
+    sensor._bus = None
+    assert sensor.init() is False
+
+
+def test_read_returns_false_without_bus(sensor):
+    sensor._bus = None
+    assert sensor.read() is False
+
+
+def test_read_positive_temperature(sensor):
+    sensor._bus.regs[0x00] = [0x0C, 0x80]  # 3200 * 0.0078125 = 25.0 C
+    assert sensor.read() is True
+    assert sensor.temperature() == pytest.approx(25.0)
+
+
+def test_read_negative_temperature(sensor):
+    sensor._bus.regs[0x00] = [0xFF, 0x00]  # -256 * 0.0078125 = -2.0 C
+    sensor.read()
+    assert sensor.temperature() == pytest.approx(-2.0)
+
+
+def test_temperature_unit_conversions(sensor):
+    sensor._bus.regs[0x00] = [0x0C, 0x80]  # 25.0 C
+    sensor.read()
+    assert sensor.temperature(tmp119.UNITS_Centigrade) == pytest.approx(25.0)
+    assert sensor.temperature(tmp119.UNITS_Fahrenheit) == pytest.approx(77.0)
+    assert sensor.temperature(tmp119.UNITS_Kelvin) == pytest.approx(298.15)
+
+
+def test_set_averaging(sensor):
+    assert sensor.set_averaging(tmp119.TMP119_AVERAGE_64X) is True
+    assert sensor.get_config() & AVG_MASK == (3 << 5)
+
+
+def test_set_read_delay(sensor):
+    assert sensor.set_read_delay(tmp119.TMP119_DELAY_16000_MS) is True
+    assert sensor.get_config() & CONV_MASK == (7 << 7)
+
+
+def test_set_averaging_preserves_read_delay(sensor):
+    sensor.set_read_delay(tmp119.TMP119_DELAY_8000_MS)
+    sensor.set_averaging(tmp119.TMP119_AVERAGE_32X)
+    assert sensor.get_config() & CONV_MASK == (6 << 7)
+    assert sensor.get_config() & AVG_MASK == (2 << 5)
+
+
+def test_set_config_round_trips_16_bits(sensor):
+    sensor.set_config(0xABCD)
+    assert sensor.get_config() == 0xABCD