Coverage for tests/test_legacy_fixtures.py: 89%

1# This file is part of lsst-images. 

2# 

3# Developed for the LSST Data Management System. 

4# This product includes software developed by the LSST Project 

5# (https://www.lsst.org). 

6# See the COPYRIGHT file at the top-level directory of this distribution 

7# for details of code ownership. 

8# 

9# Use of this source code is governed by a 3-clause BSD-style 

10# license that can be found in the LICENSE file. 

11 

12"""Read-back tests for fixtures derived from real legacy-format files. 

13 

14The ``cell_coadd`` ``as_shipped`` fixture and the ``visit_image`` ``dp1`` and 

15``dp2`` variants are derived from real archives (converted from legacy 

16formats) by ``lsst.images.tests._minify_for_fixtures``. Their whole point is 

17to prove that we can still read real-data serializations back in -- so these 

18tests just read each fixture and check its structure. 

19 

20These tests do not require ``lsst.cell_coadds`` (the ``CellCoadd`` fixture is 

21read purely through ``lsst.images``). They also do not require ``piff``: a 

22``VisitImage`` whose PSF cannot be deserialized still reads successfully, with 

23the error deferred until the PSF is actually accessed. We assert that 

24deferred behaviour directly, and only dereference the PSF when ``piff`` is 

25importable. 

26""" 

27 

28from __future__ import annotations 

29 

30from pathlib import Path 

31 

32import pytest 

33 

34from lsst.images import VisitImage 

35from lsst.images.cells import CellCoadd 

36from lsst.images.serialization import ArchiveReadError, read_archive 

37from lsst.images.tests import current_fixture_path 

38 

39FIXTURE_DIR = Path(__file__).parent / "data" / "schemas" 

40 

41try: 

42 import piff # noqa: F401 

43 

44 HAVE_PIFF = True 

45except ImportError: 

46 HAVE_PIFF = False 

47 

48 

49def test_cell_coadd() -> None: 

50 """Verify the CellCoadd fixture reads back as a multi-cell coadd. 

51 

52 Also verifies it can be subset down to a single cell. 

53 """ 

54 path = current_fixture_path(FIXTURE_DIR, "cell_coadd", variant="as_shipped") 

55 assert path.exists(), f"{path} is a committed fixture and must not go missing" 

56 

57 coadd = read_archive(path, CellCoadd) 

58 

59 assert isinstance(coadd.band, str) 

60 assert coadd.image.unit is not None 

61 # The fixture deliberately keeps more than one cell so it is a useful 

62 # test, and includes a missing cell to exercise the sparse-grid path. 

63 present = list(coadd.bounds.cell_indices()) 

64 assert len(present) >= 2 

65 assert coadd.bounds.missing, "fixture should retain a missing cell" 

66 # Provenance survived the minify and has the expected two-table shape. 

67 assert len(coadd.provenance.inputs) > 0 

68 assert len(coadd.provenance.contributions) > 0 

69 assert "polygon" in coadd.provenance.inputs.colnames 

70 

71 # Subsetting to a single present cell still works on the morphed grid. 

72 cell_bbox = coadd.grid.bbox_of(present[0]) 

73 single = coadd[cell_bbox] 

74 assert list(single.bounds.cell_indices()) == [present[0]] 

75 

76 

77@pytest.mark.parametrize("variant", ["dp1", "dp2"]) 

78def test_visit_images(variant: str) -> None: 

79 """Verify each VisitImage legacy fixture reads back with its real detector. 

80 

81 Also verifies deferred PSF behaviour when piff is unavailable. 

82 """ 

83 path = current_fixture_path(FIXTURE_DIR, "visit_image", variant=variant) 

84 assert path.exists(), f"{path} is a committed fixture and must not go missing" 

85 

86 visit_image = read_archive(path, VisitImage) 

87 

88 # Pixel planes were cropped to a small corner. 

89 assert visit_image.image.array.ndim == 2 

90 assert max(visit_image.image.array.shape) <= 16 

91 assert isinstance(visit_image.band, str) 

92 assert visit_image.image.unit is not None 

93 # The real detector (with trimmed amplifiers) round-tripped. 

94 assert len(visit_image.detector.amplifiers) >= 1 

95 assert len(visit_image.aperture_corrections) > 0 

96 

97 if HAVE_PIFF: 97 ↛ 102line 97 didn't jump to line 102 because the condition on line 97 was always true

98 assert visit_image.psf is not None 

99 else: 

100 # Reading succeeded above; the PSF error is deferred to 

101 # the point of access. 

102 with pytest.raises(ArchiveReadError): 

103 visit_image.psf