Initial Galileo receiver and SignalSim integration

tests/integration/test_signalsim_code_conventions.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import numpy as np
+import pytest
+
+from galileo_rx.signal_profiles import galileo_e1_profile
+from galileo_rx.signals.signalsim_codes import SignalSimCodeProvider
+
+
+def _checkout() -> Path:
+    candidates = [Path("signalsim/SignalSim"), Path("../SignalSim"), Path("../signalsim/SignalSim")]
+    for candidate in candidates:
+        if (candidate / "src" / "MemoryCode.dat").is_file():
+            return candidate.resolve()
+    pytest.skip("local globsky/SignalSim checkout with src/MemoryCode.dat is unavailable")
+
+
+@pytest.mark.signalsim
+def test_signalsim_e1_code_table_unpacking_and_components() -> None:
+    provider = SignalSimCodeProvider(_checkout())
+    profile = galileo_e1_profile()
+    e1b = provider.primary_code(profile, "E1B", 1)
+    e1c = provider.primary_code(profile, "E1C", 1)
+    assert e1b.dtype == np.int8 and e1b.size == 4092
+    assert e1c.dtype == np.int8 and e1c.size == 4092
+    assert set(e1b.tolist()) == {-1, 1}
+    assert not np.array_equal(e1b, e1c)
+    # First table word is 0xf5d71013 and SignalSim reads it MSB first.
+    np.testing.assert_array_equal(e1b[:8], [-1, -1, -1, -1, 1, -1, 1, -1])
+    # Every 32-word storage sector has one discarded padding bit.  Chip 1023
+    # is therefore word 32 bit 31, not word 31 bit 0.
+    words = provider._e1_words[0]  # executable check of the external table layout
+    expected_chip_1023 = -1 if (int(words[32]) >> 31) & 1 else 1
+    assert int(e1b[1023]) == expected_chip_1023
+
+
+@pytest.mark.signalsim
+def test_signalsim_e1c_secondary_is_25_symbols_lsb_first() -> None:
+    provider = SignalSimCodeProvider(_checkout())
+    secondary = provider.secondary_code(galileo_e1_profile(), "E1C", 1)
+    assert secondary is not None and secondary.size == 25
+    # 0x9b501c positions are addressed least-significant bit first.
+    expected_bits = np.asarray([(0x9B501C >> index) & 1 for index in range(25)])
+    np.testing.assert_array_equal(secondary, np.where(expected_bits == 0, 1, -1))
+    assert provider.secondary_code(galileo_e1_profile(), "E1B", 1) is None