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import pytest
_TEST = """
def test_foo(snapshot):
assert {**base} == snapshot(name="a")
assert {**base, **extra} == snapshot(name="b", diff="a")
"""
def _make_file(testdir, base, extra):
testdir.makepyfile(
test_file="\n\n".join([f"base = {base!r}", f"extra = {extra!r}", _TEST])
)
def _run_test(testdir, base, extra, expected_update_lines):
_make_file(testdir, base=base, extra=extra)
# Run with --snapshot-update, to generate/update snapshots:
result = testdir.runpytest(
"-v",
"--snapshot-update",
)
result.stdout.re_match_lines((expected_update_lines,))
assert result.ret == 0
# Run without --snapshot-update, to validate the snapshots are actually up-to-date
result = testdir.runpytest("-v")
result.stdout.re_match_lines((r"2 snapshots passed\.",))
assert result.ret == 0
def test_diff_lifecycle(testdir) -> pytest.Testdir:
# first: create both snapshots completely from scratch
_run_test(
testdir,
base={"A": 1},
extra={"X": 10},
expected_update_lines=r"2 snapshots generated\.",
)
# second: edit the base data, to change the data for both snapshots (only changes the serialized output for the base snapshot `a`).
_run_test(
testdir,
base={"A": 1, "B": 2},
extra={"X": 10},
expected_update_lines=r"1 snapshot passed. 1 snapshot updated\.",
)
# third: edit just the extra data (only changes the serialized output for the diff snapshot `b`)
_run_test(
testdir,
base={"A": 1, "B": 2},
extra={"X": 10, "Y": 20},
expected_update_lines=r"1 snapshot passed. 1 snapshot updated\.",
)
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