Files
scanengine-3/tests/test_scan_engine.py
Thomas Ales 52fdcdd9f3 Make row packing toggleable: pad (default) or strict abort
A mis-triggered row cannot be written as it arrived — v6 declares n_frames per
row in the header and has no per-row length field, so a short or long row
would shift every later row in the file. Until now the only policy was to
square it up, which keeps the scan running but leaves the affected row
indistinguishable from a good one afterwards: nothing in the file records that
it was padded.

strict_rows selects the other trade. On any frame-count mismatch the scan
stops instead of writing the row, so a data run either produces rows that mean
what the header says they mean or fails loudly. Default stays pad, so existing
behaviour is unchanged.

_warn_frame_delta becomes _check_frame_delta, since it now decides rather than
just reports. Both acquisition paths already call it before writing anything
for the row (CH1 leads SCAN_CHANNELS, and the burst path checks every row up
front), so an abort leaves the file on a whole-row boundary rather than a
half-written row — test_strict_row_packing_writes_nothing_for_the_failed_row
pins that.

Plumbed through QtScanController to a checkbox in the scan panel, persisted in
ScanDefaults alongside burst_mode. scan_format.md documents both policies and
notes that the choice is not recorded in the file.

The row-clipping setup in the padding test is now a _clip_one_row helper,
reused by the strict tests. 92 tests passing, ruff clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-02 12:32:09 -05:00

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"""Headless ScanEngine tests driven entirely by fake hardware.
These cover what can't be checked without the rig: the command sequence,
the written file layout, and abort/pause behaviour.
"""
import threading
import time
import pytest
from core.rotation import RotationAxis, RotationSettings
from core.scan_engine import (
AXIS_X, AXIS_Y, ScanAborted, ScanCallbacks, ScanEngine, ResumeState,
ResumeTarget,
)
from core.scan_geometry import ScanGeometryError, build_plan
from core.sras_format import SCAN_CHANNELS, SrasFile
from fakes import FakeScope, FakeStage, FakeT3R, Trace
SPF = 8
def make_plan(num_angles=1, y_delta=0.005):
# Small ROI well inside the stage limits: few rows, few frames per angle.
return build_plan(40.0, 30.0, 0.02, y_delta, num_angles, 0.01,
laser_freq_hz=20000.0, velocity_mm_s=100.0)
def build(tmp_path, num_angles=1, callbacks=None, resume=None, plan=None,
burst_mode=False, max_frames=4096, out_name="out.sras",
strict_rows=False, **kw):
trace = Trace()
scope = FakeScope(trace, samples_per_frame=SPF, max_frames=max_frames)
stage = FakeStage(trace, scope=scope)
t3r = FakeT3R(trace, **kw)
rotator = RotationAxis(t3r, RotationSettings())
plan = plan if plan is not None else make_plan(num_angles)
engine = ScanEngine(stage, scope, rotator, plan, tmp_path / out_name,
resume=resume,
callbacks=callbacks or ScanCallbacks(),
burst_mode=burst_mode, strict_rows=strict_rows)
return engine, trace, plan
def test_single_angle_scan_writes_readable_file(tmp_path):
engine, trace, plan = build(tmp_path)
result = engine.run()
assert not result.aborted
assert result.rows_written == plan.per_angle[0].n_rows
assert result.angles_acquired == [0]
sras = SrasFile(result.path)
assert sras.header.n_angles == 1
assert sras.header.samples_per_frame == SPF
assert sras.header.n_channels == len(SCAN_CHANNELS)
# File is complete: every declared row present on disk
assert [s.status for s in sras.angle_status()] == ["OK"]
assert len(sras.preambles) == 3
assert sras.background == bytes(range(SPF))
def test_command_sequence_order(tmp_path):
engine, trace, plan = build(tmp_path)
engine.run()
names = trace.names()
def first(name):
return names.index(name)
# Stage prepared, then scope configured, then rows executed
assert first("set_trigger_trigout_maxv") < first("set_sample_rate")
assert first("set_sample_rate") < first("transfer_fastframe")
# Velocity set for both axes before any scan move
assert trace.count("set_velocity_params") == 2
# Per row: Y positioned, then X pre-ramp, then X run
moves = trace.of("move_axis_absolute")
assert moves[0][1] == AXIS_Y
assert moves[1][1] == AXIS_X and moves[2][1] == AXIS_X
assert moves[1][2] < moves[2][2] # pre-ramp start < run-off end
# Data channels transferred (CH3 is synthesized, not read)
assert [c[1] for c in trace.of("transfer_fastframe")] == [1, 4]
def test_multi_angle_rotates_and_returns_home(tmp_path):
engine, trace, plan = build(tmp_path, num_angles=3)
engine.run()
rotations = [c[1] for c in trace.of("t3r_rotate")]
# Three angles at 0/-90/-180 → two moves out, then one back to 0
assert rotations == [-90.0, -90.0, 180.0]
# Every move waits for completion instead of sleeping a guess
assert trace.count("t3r_wait_motion_done") == len(rotations)
# GR configured once, before any rotation
assert trace.names().index("t3r_set_microstep") < trace.names().index("t3r_rotate")
sras = SrasFile(tmp_path / "out.sras")
assert [s.status for s in sras.angle_status()] == ["OK"] * 3
def test_fastframe_count_rearmed_per_angle(tmp_path):
engine, trace, plan = build(tmp_path, num_angles=3)
engine.run()
counts = [c[1] for c in trace.of("set_fastframe_count")]
assert counts == [pa.n_frames for pa in plan.per_angle]
def test_abort_before_start_raises_and_stops_early(tmp_path):
engine, trace, _ = build(tmp_path)
engine.abort()
with pytest.raises(ScanAborted):
engine.run()
assert trace.count("transfer_fastframe") == 0
def test_abort_during_prompt_unblocks(tmp_path):
"""A prompt that never returns must not deadlock an aborting scan."""
released = threading.Event()
def prompt(title, msg):
# Simulates the GUI bridge: waits until abort flips the flag.
while not engine.aborted:
if released.wait(0.01):
return
engine, trace, _ = build(tmp_path, callbacks=ScanCallbacks(prompt=prompt))
errors = []
def run():
try:
engine.run()
except ScanAborted:
errors.append("aborted")
t = threading.Thread(target=run, daemon=True)
t.start()
time.sleep(0.2) # let it reach the first prompt
engine.abort()
t.join(timeout=5)
assert not t.is_alive(), "engine deadlocked on a prompt during abort"
assert errors == ["aborted"]
def test_pause_and_resume_at_row_boundary(tmp_path):
states = []
engine, trace, plan = build(
tmp_path, num_angles=1,
callbacks=ScanCallbacks(on_paused_changed=states.append))
engine.pause()
done = threading.Event()
def run():
try:
engine.run()
except ScanAborted:
pass # only reachable via the failure escape hatch below
finally:
done.set()
t = threading.Thread(target=run, daemon=True)
t.start()
try:
# The engine's instrument-settling sleeps run before the first row,
# so poll for the pause rather than assuming a fixed delay.
deadline = time.monotonic() + 10.0
while not states and time.monotonic() < deadline:
time.sleep(0.05)
paused = bool(states)
assert paused and states[0] is True, "engine did not report the pause"
finally:
# Always release the scan thread; if the pause never arrived, abort
# too, so a failed assertion can't leave it parked forever.
if not states:
engine.abort()
engine.resume()
t.join(timeout=10)
assert done.is_set()
assert states[-1] is False
def test_dc_bias_callback_reports_per_frame_means(tmp_path):
rows = []
engine, trace, plan = build(
tmp_path, callbacks=ScanCallbacks(on_dc_bias=lambda r, m: rows.append((r, m))))
engine.run()
assert len(rows) == plan.per_angle[0].n_rows
row_idx, means = rows[0]
assert row_idx == 1
assert len(means) == plan.per_angle[0].n_frames
assert all(isinstance(v, float) for v in means)
def test_offstage_plan_rejected_before_touching_hardware(tmp_path):
trace = Trace()
scope = FakeScope(trace, samples_per_frame=SPF)
stage = FakeStage(trace, scope=scope)
# X range that runs off the 110 mm stage once ramps are added
plan = build_plan(80.0, 30.0, 40.0, 5.0, 1, 0.25,
laser_freq_hz=20000.0, velocity_mm_s=100.0)
engine = ScanEngine(stage, scope, None, plan, tmp_path / "bad.sras")
with pytest.raises(ScanGeometryError):
engine.run()
assert trace.calls == [], "hardware touched despite invalid geometry"
def test_multi_angle_without_rotator_raises(tmp_path):
trace = Trace()
engine = ScanEngine(FakeStage(trace), FakeScope(trace, samples_per_frame=SPF),
None, make_plan(3), tmp_path / "x.sras")
with pytest.raises(RuntimeError, match="T3R rotation stage"):
engine.run()
def test_missing_hardware_raises(tmp_path):
trace = Trace()
with pytest.raises(RuntimeError, match="BBD202"):
ScanEngine(None, FakeScope(trace), None, make_plan(),
tmp_path / "x.sras").run()
with pytest.raises(RuntimeError, match="Oscilloscope"):
ScanEngine(FakeStage(trace), None, None, make_plan(),
tmp_path / "x.sras").run()
def test_resume_seeks_to_angle_offset_and_skips_others(tmp_path):
# First produce a complete 3-angle file
engine, trace, plan = build(tmp_path, num_angles=3)
engine.run()
path = tmp_path / "out.sras"
original = path.read_bytes()
sras = SrasFile(path)
statuses = sras.angle_status()
target = statuses[1]
resume = ResumeState(
path=path,
targets=[ResumeTarget(target.index, target.data_offset,
target.n_rows, target.angle_deg)],
samples_per_frame=SPF,
)
engine2, trace2, _ = build(tmp_path, num_angles=3, resume=resume)
result = engine2.run()
assert result.angles_acquired == [1]
# Only the middle angle's rows were re-acquired
assert result.rows_written == plan.per_angle[1].n_rows
rewritten = path.read_bytes()
assert len(rewritten) == len(original)
# Angle 0's block is untouched; angle 1's changed (fresh frame data)
a1_start, a1_end = target.data_offset, target.data_offset + target.row_bytes * target.n_rows
assert rewritten[:a1_start] == original[:a1_start]
assert rewritten[a1_start:a1_end] != original[a1_start:a1_end]
assert rewritten[a1_end:] == original[a1_end:]
def test_resume_record_length_mismatch_rejected(tmp_path):
engine, trace, plan = build(tmp_path)
engine.run()
path = tmp_path / "out.sras"
resume = ResumeState(path=path,
targets=[ResumeTarget(0, 0, 1, 0.0)],
samples_per_frame=SPF + 1) # scope changed
engine2, _, _ = build(tmp_path, resume=resume)
with pytest.raises(RuntimeError, match="record length"):
engine2.run()
# ── Burst acquisition ────────────────────────────────────────────────────────
# 6 rows × 4 frames/row; max_frames=14 gives 14//4 = 3 rows per burst, so the
# angle needs two bursts and the second is not a whole burst wide.
BURST_PLAN = dict(y_delta=0.05)
BURST_MAX_FRAMES = 14
def test_burst_and_serial_produce_identical_files(tmp_path):
"""The whole point: burst mode must be a pure acquisition optimisation."""
plan = make_plan(**BURST_PLAN)
assert plan.per_angle[0].n_rows == 6 and plan.per_angle[0].n_frames == 4
serial, _, _ = build(tmp_path, plan=plan, out_name="serial.sras")
serial.run()
burst, _, _ = build(tmp_path, plan=plan, out_name="burst.sras",
burst_mode=True, max_frames=BURST_MAX_FRAMES)
burst.run()
assert (tmp_path / "burst.sras").read_bytes() == \
(tmp_path / "serial.sras").read_bytes()
def test_burst_multi_angle_file_is_complete(tmp_path):
plan = make_plan(num_angles=3, **BURST_PLAN)
engine, trace, _ = build(tmp_path, plan=plan, burst_mode=True,
max_frames=BURST_MAX_FRAMES)
result = engine.run()
assert result.rows_written == plan.total_rows
assert result.angles_acquired == [0, 1, 2]
sras = SrasFile(tmp_path / "out.sras")
assert [s.status for s in sras.angle_status()] == ["OK"] * 3
def test_burst_gates_the_flyback_and_runs_once_per_burst(tmp_path):
plan = make_plan(**BURST_PLAN)
engine, trace, _ = build(tmp_path, plan=plan, burst_mode=True,
max_frames=BURST_MAX_FRAMES)
engine.run()
# Two bursts (3 + 3 rows), two preflight acquisitions, one background.
runs = [c for c in trace.of("write") if c[1] == "ACQuire:STATE RUN"]
assert len(runs) == 5
# Every acquiring pass is bracketed by an arm/disarm, so the gate is low
# for each flyback. 6 rows + 1 preflight pass = 7 arms.
gate = [c[2] for c in trace.of("arm_scan_gate")]
assert gate.count(True) == 7
# No two arms without a disarm between them — that is what would let a
# flyback into the acquisition. (A repeated disarm is just defensive.)
for a, b in zip(gate, gate[1:], strict=False):
assert not (a and b), f"acquiring pass with no disarm before it: {gate}"
assert gate[-1] is False, "scan left the gate armed"
# One bulk transfer per data channel per burst, none per row.
assert [(c[1], c[2]) for c in trace.of("transfer_fastframe_bulk")] == [
(1, 12), (4, 12), (1, 12), (4, 12)]
assert trace.count("transfer_fastframe") == 0
def test_burst_preflight_rejects_a_leaky_gate(tmp_path):
plan = make_plan(**BURST_PLAN)
engine, trace, _ = build(tmp_path, plan=plan, burst_mode=True,
max_frames=BURST_MAX_FRAMES)
stage = engine._stage
# A gate that ignores the disable request — the failure mode the preflight
# exists to catch (TRIGOUT_GATE_OFF set to the wrong mode value).
def stuck_gate(axis, armed, verify=True):
trace.record("arm_scan_gate", axis, bool(armed))
stage.gate_armed = True
stage.arm_scan_gate = stuck_gate
with pytest.raises(RuntimeError, match="not idling low"):
engine.run()
def test_burst_preflight_rejects_a_dark_laser(tmp_path):
"""A gate that never fires would let a leak check pass vacuously."""
plan = make_plan(**BURST_PLAN)
engine, trace, _ = build(tmp_path, plan=plan, burst_mode=True,
max_frames=BURST_MAX_FRAMES)
engine._stage.attach_scope(None) # no pulses ever reach the scope
with pytest.raises(RuntimeError, match="no frames acquired"):
engine.run()
def _clip_one_row(engine, which_pass=2, lost=1):
"""Make one acquiring pass come up `lost` frames short.
`which_pass` counts acquiring passes from 1, so the default clips the
second data row (row 2) — far enough in that a mishandled short row shows
up as a shift in the rows after it.
"""
scope = engine._scope
real_acquire = scope.acquire_frames
passes = {"n": 0}
def clipped(n):
if scope._running:
passes["n"] += 1
if passes["n"] == which_pass:
n -= lost
real_acquire(n)
scope.acquire_frames = clipped
@pytest.mark.parametrize("burst_mode", [False, True])
def test_short_row_is_padded_to_declared_frame_count(tmp_path, burst_mode):
"""A clipped row must not shift every later row in the file.
v6 declares n_frames per row up front and has no per-row length, so an
under-triggered row has to be squared up. In burst mode this also proves
the splitter advances by what actually arrived, not by n_frames.
"""
warnings = []
plan = make_plan(**BURST_PLAN)
engine, trace, _ = build(
tmp_path, plan=plan, burst_mode=burst_mode,
max_frames=BURST_MAX_FRAMES,
callbacks=ScanCallbacks(on_status=warnings.append))
# The preflight is covered by its own tests; skipping it keeps the
# acquiring-pass count below identical in both modes.
engine._preflight_done = True
_clip_one_row(engine)
result = engine.run()
assert result.rows_written == 6
assert any("Row 2: 3 frames acquired, 4 expected" in w for w in warnings)
assert any("zero-padded" in w for w in warnings)
sras = SrasFile(tmp_path / "out.sras")
assert [s.status for s in sras.angle_status()] == ["OK"]
# The padding lands at the end of the short row, not in the next one.
assert bytes(sras.load_row(0, 1, 0)[-1]) == bytes(SPF)
assert bytes(sras.load_row(0, 2, 0)[0]) != bytes(SPF)
# ── Strict row packing ───────────────────────────────────────────────────────
@pytest.mark.parametrize("burst_mode", [False, True])
def test_strict_row_packing_aborts_on_a_short_row(tmp_path, burst_mode):
"""Strict mode fails the scan instead of silently squaring a row up.
The default padding keeps the file readable but makes a mis-triggered row
indistinguishable from a good one after the fact, since v6 records no
per-row frame count. Strict mode trades the salvaged rows for knowing.
"""
plan = make_plan(**BURST_PLAN)
engine, _, _ = build(tmp_path, plan=plan, burst_mode=burst_mode,
max_frames=BURST_MAX_FRAMES, strict_rows=True)
engine._preflight_done = True
_clip_one_row(engine)
with pytest.raises(RuntimeError, match="Row 2: 3 frames acquired, 4 expected"):
engine.run()
@pytest.mark.parametrize("burst_mode", [False, True])
def test_strict_row_packing_does_not_disturb_a_clean_scan(tmp_path, burst_mode):
"""Strict mode is inert when every row acquires what it declared."""
plan = make_plan(**BURST_PLAN)
engine, _, _ = build(tmp_path, plan=plan, burst_mode=burst_mode,
max_frames=BURST_MAX_FRAMES, strict_rows=True)
engine._preflight_done = True
result = engine.run()
assert result.rows_written == plan.total_rows
sras = SrasFile(tmp_path / "out.sras")
assert [s.status for s in sras.angle_status()] == ["OK"]
def test_strict_row_packing_writes_nothing_for_the_failed_row(tmp_path):
"""The abort must not leave a half-written row behind.
CH1 leads SCAN_CHANNELS, so the frame count is known before any of the
row's channels are written — the file should end on a whole-row boundary.
"""
plan = make_plan(**BURST_PLAN)
engine, _, _ = build(tmp_path, plan=plan, strict_rows=True)
engine._preflight_done = True
_clip_one_row(engine)
with pytest.raises(RuntimeError, match="Strict row packing"):
engine.run()
# Row 1 was written in full; row 2 aborted before writing anything, so
# the file ends exactly on a row boundary.
sras = SrasFile(tmp_path / "out.sras")
written = (tmp_path / "out.sras").stat().st_size - sras.data_start_offset
assert written == sras.row_bytes(0)
def test_engine_imports_without_qt():
"""The engine must be usable from a non-Qt front end."""
import subprocess
import sys
code = (
"import sys;"
"sys.modules['PyQt6'] = None;"
"import core.scan_engine, core.rotation, core.scope_sras,"
" core.scan_resume, core.sras_format, core.scan_geometry;"
"print('ok')"
)
out = subprocess.run([sys.executable, "-c", code], capture_output=True,
text=True, cwd=str(__import__('pathlib').Path(__file__).parent.parent))
assert out.returncode == 0, out.stderr
assert "ok" in out.stdout