Draft: Resolve "Daskify LISA Instrument"

Closes #158

Note that we've divided up this MR into smaller tasks (see issue), which correspond to relatively independent features to be implemented in their own branches created of 158-daskify-lisa-instrument. We can then open a MR for each of them, review, and merge to 158-daskify-lisa-instrument.

tests/test_fir_filters_dask.py

+"""Unit tests for the module fir_filters_dask"""
+
+import numpy as np
+import dask.array as da
+import pytest
+
+from lisainstrument.fir_filters_numpy import (
+    DefFilterFIR,
+    EdgeHandling,
+    make_filter_fir_numpy,
+)
+from lisainstrument.fir_filters_dask import make_filter_fir_dask
+
+
+def test_filter_dask_fir():
+    """Ensure dask-based FIR filter results agree with numpy based ones"""
+
+    sig_np = np.array([1.0, 1.0, 1.0, 0.01, 0, 1, 0.2, 0.1])
+
+    coeffs = [0.1, 0.7, 0.1, 0.1]
+    fir = DefFilterFIR(filter_coeffs=coeffs, offset=-1)
+
+    op_np = make_filter_fir_numpy(fir, EdgeHandling.ZEROPAD, EdgeHandling.ZEROPAD)
+    op_da = make_filter_fir_dask(fir, EdgeHandling.ZEROPAD, EdgeHandling.ZEROPAD)
+
+    out_np = op_np(sig_np)
+
+    # ~ print("testing FIR filtering of chunked dask array")
+    for chunksize in (2, 3, 4, 5, 6, 7, 8):
+        sig_da = da.from_array(sig_np, chunks=chunksize)
+        # ~ print(sig_da)
+
+        out_da = op_da(sig_da).compute()
+
+        assert len(out_np) == len(out_da)
+        assert out_np == pytest.approx(out_da, abs=1e-14, rel=0)