tests: Add a few tests of waveforms backed by memory-mapped files

tests/acceptance/__init__.py

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+"""Acceptance tests for the nitypes package."""

tests/acceptance/waveform/__init__.py

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+"""Acceptance tests for the nitypes.waveform package."""

tests/acceptance/waveform/test_memmap.py

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+from __future__ import annotations
+
+import struct
+from pathlib import Path
+
+import numpy as np
+import pytest
+
+from nitypes.waveform import AnalogWaveform
+
+
+@pytest.mark.parametrize("copy", [False, True])
+def test___memmap_array_1d___create_waveform_from_array___waveform_contains_memmap_data(
+    tmp_path: Path, copy: bool
+) -> None:
+    memmap_path = tmp_path / "memmap_array.bin"
+    memmap_path.write_bytes(struct.pack("4d", 1.23, -4.56, 7e89, 1e-23))
+    memmap_array = np.memmap(memmap_path, np.float64)
+
+    waveform = AnalogWaveform.from_array_1d(memmap_array, copy=copy)
+
+    assert list(waveform.raw_data) == [1.23, -4.56, 7e89, 1e-23]
+
+
+@pytest.mark.parametrize("copy", [False, True])
+def test___memmap_array_2d___create_waveforms_from_array___waveforms_contains_memmap_data(
+    tmp_path: Path, copy: bool
+) -> None:
+    memmap_path = tmp_path / "memmap_array.bin"
+    memmap_path.write_bytes(struct.pack("6d", 1.23, -4.56, 7e89, 1e-23, 456.0, 7.89))
+    memmap_array = np.memmap(memmap_path, np.float64, shape=(2, 3))
+
+    waveforms = AnalogWaveform.from_array_2d(memmap_array, copy=copy)
+
+    assert len(waveforms) == 2
+    assert list(waveforms[0].raw_data) == [1.23, -4.56, 7e89]
+    assert list(waveforms[1].raw_data) == [1e-23, 456.0, 7.89]
+
+
+def test___memmap_waveform___append___waveform_writes_to_memmap(tmp_path: Path) -> None:
+    memmap_path = tmp_path / "memmap_array.bin"
+    memmap_array = np.memmap(memmap_path, np.float64, "w+", shape=10)
+    waveform = AnalogWaveform.from_array_1d(memmap_array, copy=False, sample_count=0)
+
+    waveform.append(np.array([1.23, -4.56, 7e89, 1e-23]))
+    memmap_array.flush()
+
+    memmap_bytes = memmap_path.read_bytes()
+    memmap_data = struct.unpack_from("4d", memmap_bytes)
+    assert memmap_data == (1.23, -4.56, 7e89, 1e-23)
+
+
+def test___memmap_waveforms___append___waveforms_write_to_memmap(tmp_path: Path) -> None:
+    memmap_path = tmp_path / "memmap_array.bin"
+    memmap_array = np.memmap(memmap_path, np.float64, "w+", shape=(2, 10))
+    waveforms = AnalogWaveform.from_array_2d(memmap_array, copy=False, sample_count=0)
+
+    waveforms[0].append(np.array([1.23, -4.56, 7e89]))
+    waveforms[1].append(np.array([1e-23, 456.0, 7.89]))
+    memmap_array.flush()
+
+    memmap_bytes = memmap_path.read_bytes()
+    memmap_data0 = struct.unpack_from("3d", memmap_bytes, offset=0)
+    memmap_data1 = struct.unpack_from("3d", memmap_bytes, offset=80)
+    assert memmap_data0 == (1.23, -4.56, 7e89)
+    assert memmap_data1 == (1e-23, 456.0, 7.89)