docs/tests/datasets_tests.md

datasets_tests.md — Test Plan for docs/modules/datasets.md

Owner: Person B (Rewards & Tests), co-authored with Person C (Training & Data) Target module: DRIFTCALL/docs/modules/datasets.md (final sealed) Implements coverage for: DESIGN.md §8 (§§8.1, 8.2, 8.3, 8.4, 8.5, 8.6) and CLAUDE.md §3.1 Frameworks: pytest, hypothesis, pytest-cov Status: DRAFT — pending ≥ 1 fresh critic round (test-plan gate is lighter per CLAUDE.md §3.2 Batch D4)

---

0. Scope & Non-goals

datasets.md specifies four on-disk data layers (L1 templates/i18n, L2 drift-patterns + api-schemas, L3 audio manifest, L4 SFT warmup) plus a one-shot HF Hub publication contract. Every loader is a lazy singleton that NFC-normalizes on read, validates against a frozen dataclass schema, and raises a typed DatasetError subclass on any shape / license / lineage / leak violation.

This plan covers:

1. Constructibility + immutability of every frozen dataclass declared in datasets.md §4 (§4.1 – §4.7).
2. Canonical JSON serialization — byte-identical output of json.dumps(row, ensure_ascii=False, sort_keys=True, separators=(",",":")) across Python / libc versions (datasets.md §3.1 invariant #6).
3. Lineage hash triple — every BriefRow carries catalogue_hash / templates_sha256 / i18n_sha256, and any mismatch at eval-load raises CatalogueHashMismatchError (datasets.md §3.5 invariant #9, §5).
4. Size + contents invariants — TemplateLibrary has exactly 20 templates at v1.0, DriftPatternLibrary has exactly 20 patterns, APISchemaRegistry exactly 14 schemas over 5 domains (datasets.md §3.5 invariants #2 / #3 / #4).
5. License bundle integrity — root LICENSE contains the full verbatim Apache-2.0 text (byte length ≥ 11 000, canonical header string present, SHA pinned in fixture), LICENSES.md markdown table parses (datasets.md §3.4).
6. Audio manifest provenance — AudioClip.source only accepts the single Literal["real_indicvoices_r"]; the string "synth_kokoro" is rejected at dataclass-construction time (datasets.md §4.5).
7. Publication determinism — random.Random(20260425).sample(range(0, 20_000_000), 15_000) is byte-identical across re-runs; val seeds are list(range(20_000_000, 20_000_500)); train ∩ val = ∅ (datasets.md §2.4, §3.1, §3.5 invariants #5 / #6).
8. SFT restart recovery — training/sft_generator.py appends one canonical-JSON line + os.fsync(fd) per trajectory, rehydrates generation_batch_id on restart, emits monotonic generation_index, and raises PartialSFTCorpusError on final-count mismatch (datasets.md §4.6, §7 edge 11).
9. License-cache FTS5 schema — scripts/build_license_cache.py produces data/.license_cache/{sgd,mtop}.idx with CREATE VIRTUAL TABLE licensed_text USING fts5(chunk_text, source_id); and 5-gram tokenization (datasets.md §9.1).
10. HF dataset-card frontmatter — README.md YAML frontmatter parses via the HF datasets loader (datasets.md §8.6).

Every test below maps to one numbered clause in datasets.md. Clause references are embedded in each test docstring as datasets.md §X.Y / datasets.md §7 edge N.

---

1. Unit tests

All unit tests live in DRIFTCALL/tests/data/. Import surface under test:

from driftcall.data.models import (
    TemplateLibrary, I18nLibrary,
    DriftPatternLibrary, APISchemaRegistry, APISchema,
    AudioManifest, AudioClip,
    SFTCorpus, SFTTrajectory,
    BriefRow,
)
from driftcall.data.loaders import (
    load_templates, load_i18n,
    load_drift_patterns, load_api_schemas,
    load_audio_manifest, load_sft_corpus,
)
from driftcall.data.errors import (
    DatasetError, DatasetFileMissingError, MalformedYAMLError, MalformedJSONError,
    DatasetSchemaError, UnknownLanguageKeyError, LicenseConflictError,
    TrainValLeakError, DriftPatternOrphanError, ChecksumMismatchError,
    UnicodeNFDError, PIIDetectedError, DuplicateDriftPatternIdError,
    CatalogueHashMismatchError, PartialSFTCorpusError,
)
from training.data_export import canonical_dumps, sample_train_seeds, val_seeds
from training.sft_generator import append_trajectory, resume_batch
from scripts.build_license_cache import build_index, FTS5_SCHEMA_DDL

Fixtures (§5) come from tests/data/conftest.py and tests/conftest.py.

1.1 BriefRow — frozen dataclass + 13-field contract

#	Test name	Asserts	Maps to
U1	test_brief_row_has_exactly_thirteen_fields	len(dataclasses.fields(BriefRow)) == 13; field names equal the ordered tuple ("episode_id","seed","stage","language","domain","template_id","goal","drift_schedule","catalogue_hash","templates_sha256","i18n_sha256","generator_version","created_ts_ist").	datasets.md §4.7
U2	test_brief_row_is_frozen	Building from brief_row_happy fixture, every attempted assignment (row.seed = 7, row.episode_id = "x", etc.) raises dataclasses.FrozenInstanceError. Parametrized over all 13 fields.	datasets.md §3.5 invariant #1 (immutability), §4.7
U3	test_brief_row_happy_construct_roundtrip	brief_row_happy constructs; dataclasses.asdict(row) returns a dict with 13 keys matching the spec; all string fields are NFC.	datasets.md §4.7
U4	test_brief_row_missing_required_field_raises	BriefRow() raises TypeError (no defaults — every field is required). Parametrized: supplying 12 of 13 fields also raises.	datasets.md §4.7
U5	test_brief_row_stage_literal_enforced	BriefRow(..., stage=4) is statically illegal; at runtime a DatasetSchemaError is raised by load_* on a stage value ∉ {1,2,3}.	datasets.md §4.7
U6	test_brief_row_domain_literal_enforced	A domain="payment" row is rejected at load time (BriefRow.domain is the 4-value primary-domain literal — payment is L2-only and does not appear in publication).	datasets.md §4.7, §3.5 invariant #4
U7	test_brief_row_created_ts_ist_must_carry_plus0530_offset	load_briefs("train/briefs.jsonl") rejects a row whose created_ts_ist does not end in +05:30.	datasets.md §4.7

1.2 Canonical JSON ordering

#	Test name	Asserts	Maps to
U8	test_canonical_dumps_sorts_keys	canonical_dumps({"b":1,"a":2}) == '{"a":2,"b":1}'; output contains no spaces; no trailing newline.	datasets.md §3.1 canonical-JSON block
U9	test_canonical_dumps_preserves_devanagari	canonical_dumps({"city":"बेंगलुरु"}) contains the literal Devanagari bytes (UTF-8), NOT क… escapes. Exact bytes asserted with ==.	datasets.md §3.1 (ensure_ascii=False)
U10	test_canonical_dumps_exact_separators	The serialized form of {"a":1,"b":2} equals b'{"a":1,"b":2}' byte-for-byte; no whitespace between , / : and neighbours.	datasets.md §3.1 canonical-JSON block
U11	test_canonical_dumps_brief_row_matches_golden	canonical_dumps(asdict(brief_row_happy)) equals the golden line in §8.5 of datasets.md byte-for-byte.	datasets.md §8.5
U12	test_canonical_dumps_is_idempotent	canonical_dumps(json.loads(canonical_dumps(row))) == canonical_dumps(row) for 100 random fixture perturbations (fuzzed via hypothesis — see §2).	datasets.md §3.1, §3.5 invariant #6

1.3 Lineage hashes (catalogue_hash, templates_sha256, i18n_sha256)

#	Test name	Asserts	Maps to
U13	test_catalogue_hash_matches_drifts_yaml_bytes	catalogue_hash == hashlib.sha256(Path("data/drift_patterns/drifts.yaml").read_bytes()).hexdigest(); length 64 hex chars; lowercase.	datasets.md §4.7, §3.5 invariant #9
U14	test_templates_sha256_matches_templates_yaml_bytes	templates_sha256 == sha256(templates.yaml) byte-for-byte.	datasets.md §4.7
U15	test_i18n_sha256_matches_i18n_yaml_bytes	i18n_sha256 == sha256(i18n.yaml) byte-for-byte.	datasets.md §4.7
U16	test_catalogue_hash_mismatch_raises_at_load	Given brief_row_happy serialized with catalogue_hash="deadbeef…" (wrong), load_briefs(path) raises CatalogueHashMismatchError naming the offending field(s).	datasets.md §3.5 invariant #9, §5 (CatalogueHashMismatchError)
U17	test_hash_computation_is_stable_across_reruns	Computing the three hashes twice in the same process returns identical values; computing across two subprocesses (via subprocess.check_output) also identical.	datasets.md §3.5 invariant #6

1.4 AudioClip.source excludes synth

#	Test name	Asserts	Maps to
U18	test_audio_clip_source_accepts_real_only	AudioClip(..., source="real_indicvoices_r", ...) constructs; AudioClip(..., source="synth_kokoro", ...) raises DatasetSchemaError at load.	datasets.md §4.5
U19	test_audio_manifest_rejects_synth_row	A MANIFEST.jsonl line containing "source":"synth_kokoro" causes load_audio_manifest to raise DatasetSchemaError("source must be 'real_indicvoices_r'").	datasets.md §4.5
U20	test_audio_manifest_duration_upper_bound	AudioClip(..., duration_s=20.01) loads raise DatasetSchemaError; 20.00 OK (DESIGN.md §9 upper bound).	datasets.md §4.5

1.5 TemplateLibrary.size == 20 at v1.0

#	Test name	Asserts	Maps to
U21	test_template_library_size_is_exactly_twenty_at_v1	len(load_templates().templates) == 20; len(templates) % 5 == 0; generator_version.startswith("driftcall-1.0").	datasets.md §3.5 invariant #4, §4.1
U22	test_template_library_four_domains_five_each	Grouped by template.domain, exactly 4 primary domains are present (airline, cab, restaurant, hotel), 5 templates each. Payment is NOT a primary-domain template owner.	datasets.md §4.1, §3.5 invariant #4
U23	test_template_library_every_language_every_template	For every template, set(template.language_variants.keys()) == {"hi","ta","kn","en","hinglish"}; missing key raises DatasetSchemaError at load.	datasets.md §3.5 invariant #4, §7 edge 1
U24	test_template_library_future_version_monotonic_growth	Synthesize a mock templates.yaml with 25 entries tagged generator_version="driftcall-1.1.0"; load_templates accepts it (monotonic growth invariant holds: len >= 20 and len % 5 == 0).	datasets.md §4.1

1.6 LICENSES.md schema parse + LICENSE verbatim Apache-2.0

#	Test name	Asserts	Maps to
U25	test_root_license_byte_length_at_least_11000	Path("LICENSE").read_bytes().__len__() >= 11_000.	datasets.md §3.4
U26	test_root_license_contains_apache_canonical_header	The bytes b"Apache License\n Version 2.0, January 2004" appear at the top of LICENSE.	datasets.md §3.4
U27	test_root_license_sha256_pinned	sha256(LICENSE bytes) == APACHE_2_0_CANONICAL_SHA (pinned constant 8a0d778…; exact value locked in tests/data/fixtures/license_hashes.py).	datasets.md §3.4
U28	test_audio_licenses_md_embeds_full_apache_text	data/audio/LICENSES.md byte length ≥ 11 000 AND contains the canonical Apache header.	datasets.md §3.4
U29	test_sft_licenses_md_embeds_full_apache_text	Same check for data/sft_warmup/LICENSES.md.	datasets.md §3.4
U30	test_licenses_md_table_schema_parses	The markdown table in each LICENSES.md parses with columns in exact order `["utterance_id"	"trajectory_id", "upstream_source", "upstream_license", "attribution_required", "notes"]; every row has 5 cells; attribution_required ∈ {"yes","no"}`.

1.7 Seed selection — deterministic, byte-identical

#	Test name	Asserts	Maps to
U31	test_train_seed_sampling_is_deterministic	sample_train_seeds() == random.Random(20260425).sample(range(0, 20_000_000), 15_000); re-running the function twice yields identical lists (element-wise equal + ordering identical).	datasets.md §2.4
U32	test_train_seed_count_is_fifteen_thousand	len(sample_train_seeds()) == 15_000; all elements in [0, 20_000_000); no duplicates.	datasets.md §2.4, §3.1
U33	test_val_seeds_are_exact_contiguous_slice	val_seeds() == list(range(20_000_000, 20_000_500)); len == 500; first == 20_000_000; last == 20_000_499.	datasets.md §2.4
U34	test_train_val_disjoint	set(sample_train_seeds()).isdisjoint(set(val_seeds())); assert raises TrainValLeakError if injected seed 20_000_050 is spliced into train output.	datasets.md §3.5 invariant #5, §7 edge 5

1.8 SFT restart recovery + PartialSFTCorpusError

#	Test name	Asserts	Maps to
U35	test_sft_append_one_line_fsyncs	append_trajectory(fd, traj) writes exactly one canonical-JSON line ending \n and invokes os.fsync(fd) once per call (verified via unittest.mock.patch("os.fsync")).	datasets.md §4.6
U36	test_sft_generation_batch_id_monotonic_within_batch	Batch generates N=10 trajectories; all carry identical generation_batch_id (uuid4); generation_index values are [0..9] strictly monotonic and contiguous.	datasets.md §4.6
U37	test_sft_restart_rehydrates_batch_id	Given trajectories.jsonl pre-populated with 3 rows (batch_id B), call resume_batch(path); returned (batch_id, next_index) == (B, 3). New rows appended reuse B.	datasets.md §4.6, §7 edge 11
U38	test_sft_partial_corpus_error_on_resume_count_mismatch	Corpus file has 298 rows with target_count=300 recorded in corpus metadata; load_sft_corpus raises PartialSFTCorpusError("expected 300, got 298").	datasets.md §4.6, §5 (PartialSFTCorpusError), §7 edge 11
U39	test_sft_generator_final_count_validation	training/sft_generator.py run with --target-count 5 but Sarvam-M drops 1 response → generator raises PartialSFTCorpusError post-loop (not silently).	datasets.md §4.6

1.9 License-cache FTS5 schema

#	Test name	Asserts	Maps to
U40	test_license_cache_schema_ddl_is_exact	FTS5_SCHEMA_DDL == "CREATE VIRTUAL TABLE licensed_text USING fts5(chunk_text, source_id);" — byte-for-byte.	datasets.md §9.1
U41	test_license_cache_uses_5gram_tokenizer	Introspect sqlite PRAGMA fts5_integrity_check + the CREATE VIRTUAL TABLE statement records tokenize = 'unicode61' with 5-gram config; build_index(tokenizer="trigram") raises ValueError.	datasets.md §9.1
U42	test_license_cache_built_is_read_only_in_ci	In CI mode (DRIFTCALL_CI=1), invoking build_index raises RuntimeError("license cache is read-only in CI").	datasets.md §9.1

1.10 README.md YAML frontmatter — HF dataset loader parse

#	Test name	Asserts	Maps to
U43	test_readme_frontmatter_parses_with_pyyaml	yaml.safe_load(frontmatter_block) yields a dict with keys {license, language, size_categories, task_categories, pretty_name, configs, dataset_info}; license == "apache-2.0"; language == ["hi","ta","kn","en"].	datasets.md §8.6
U44	test_readme_frontmatter_loads_via_hf_datasets	datasets.load_dataset(str(bundle_dir)) (HF loader) returns a DatasetDict with {"train","val"} splits; train.num_rows == 15_000; val.num_rows == 500. Skipped if datasets not installed.	datasets.md §8.6
U45	test_readme_frontmatter_features_flat_columns_only	The features block lists only the 6 flat columns {episode_id, seed, stage, language, domain, template_id}; nested goal/drift_schedule are NOT pre-declared (auto-inferred).	datasets.md §8.6

1.11 Miscellaneous spec wiring

#	Test name	Asserts	Maps to
U46	test_load_drift_patterns_count_equals_twenty	len(load_drift_patterns().patterns) == 20; every drift_type ∈ {"schema","policy","tnc","pricing","auth"}.	datasets.md §3.5 invariant #2
U47	test_load_api_schemas_count_equals_fourteen_across_five_domains	APISchemaRegistry reports exactly 14 schemas keyed {airline:{v1,v2,v3}, cab:{v1,v2,v3}, restaurant:{v1,v2,v3}, hotel:{v1,v2,v3}, payment:{v1,v2}}.	datasets.md §3.5 invariant #3
U48	test_drift_pattern_orphan_raises	YAML with from_version="v5" (nonexistent) raises DriftPatternOrphanError.	datasets.md §5, §7 edge 6
U49	test_duplicate_drift_pattern_id_raises	YAML with two entries sharing id: airline.price_rename raises DuplicateDriftPatternIdError citing both line numbers.	datasets.md §5, §7 edge 10
U50	test_nfc_normalization_applied_at_load	A templates YAML authored with NFD Kannada weekday normalizes to NFC on load; unicodedata.is_normalized("NFC", v) is True for every loaded string.	datasets.md §3.5 invariant #1, §7 edge 2
U51	test_pii_10_digit_run_raises	An authored string containing "9876543210" outside IATA / timestamp contexts raises PIIDetectedError.	datasets.md §3.5 invariant #8, §3.1
U52	test_license_header_missing_raises	A YAML file without the # SPDX-License-Identifier: leading comment raises DatasetSchemaError at load.	datasets.md §3.5 invariant #7
U53	test_audio_manifest_sha256_mismatch_raises	Corrupt a wav byte; load_audio_manifest raises ChecksumMismatchError citing expected vs actual.	datasets.md §5, §7 edge 8
U54	test_sft_trajectory_val_seed_raises	SFTTrajectory(goal_seed=20_000_042, …) on load raises TrainValLeakError.	datasets.md §5, §7 edge 9
U55	test_loader_is_singleton_per_path	load_templates() twice returns the same object by identity (is); called with a different path= yields a distinct instance cached separately.	datasets.md §3.2

Total unit tests: 55 (target ≥ 35).

---

2. Property tests

All property tests live in DRIFTCALL/tests/data/test_properties.py using hypothesis.

#	Property	Strategy	Maps to
P1	Byte-identical re-runs of data_export. For any seed s == 20260425, two invocations of data_export.main(seed=s) produce byte-identical train/briefs.jsonl + val/briefs.jsonl (SHA-256 hashes match).	Fixed seed + hypothesis-generated minor perturbations (run order, tmpdir path).	datasets.md §3.5 invariant #6
P2	BriefRow is frozen. For any BriefRow instance generated by brief_row_strategy(), assigning to any of its 13 fields raises FrozenInstanceError. Hypothesis enumerates field name and value type.	st.builds(BriefRow, …) + st.sampled_from(fields_of(BriefRow)).	datasets.md §3.5 invariant #1, §4.7
P3	Seed-range disjointness. For any pair (t, v) where t ∈ [0, 20_000_000) and v ∈ [20_000_000, 20_000_500), t != v and both sets generated by the spec are disjoint. Hypothesis samples 10 000 pairs.	st.tuples(st.integers(min_value=0, max_value=19_999_999), st.integers(min_value=20_000_000, max_value=20_000_499)).	datasets.md §3.5 invariant #5, §2.4
P4	Canonical JSON determinism under key permutation. For any dict d and any permutation d' of its keys, canonical_dumps(d) == canonical_dumps(d') byte-for-byte.	st.dictionaries(st.text(), st.one_of(st.integers(), st.text())) + .map(shuffle_keys).	datasets.md §3.1, §3.5 invariant #6
P5	NFC idempotence. For any string s, nfc(nfc(s)) == nfc(s); load_templates applied twice yields the same library by hash.	st.text(alphabet=st.characters(min_codepoint=0x0900, max_codepoint=0x0DFF)) — Devanagari + Tamil + Kannada ranges.	datasets.md §3.5 invariant #1, §7 edge 2
P6	Catalogue-hash round-trip. For any brief_row_happy-shaped row with a synthetic YAML y, sha256(y) computed by load_* equals hashlib.sha256(y.encode("utf-8")).hexdigest() (i.e., loader uses the same algorithm as the spec).	st.text(alphabet=st.characters(whitelist_categories=("Ll","Lu","Nd"))).	datasets.md §3.5 invariant #9, §4.7

Total properties: 6 (target ≥ 5).

---

3. Integration tests

All integration tests live in DRIFTCALL/tests/data/test_integration.py. Marked @pytest.mark.integration — run by CI and by pytest -m integration locally.

#	Test name	Scenario	Maps to
I1	test_full_data_export_writes_train_and_val_jsonl	Invoke training/data_export.main(--out-train, --out-val, --n-train 15000, --n-val 500, --seed 20260425) in a tmpdir; assert both files exist, each line parses as canonical JSON, train has 15 000 rows, val has 500, and the set of (seed) values across both splits equals set(train_seeds) ∪ set(val_seeds).	datasets.md §2.4
I2	test_full_data_export_round_trip_hashes	Re-run I1 a second time in a separate tmpdir; assert sha256(train/briefs.jsonl) and sha256(val/briefs.jsonl) match the first-run hashes byte-for-byte.	datasets.md §3.5 invariant #6
I3	test_hf_upload_dry_run	Run hf upload <org>/driftcall-indic-briefs data/publication/ . --repo-type dataset --dry-run (via subprocess). Assert exit 0; stdout lists exactly the files enumerated in datasets.md §2.1 publication tree; no network request fires (use HF_HUB_OFFLINE=1).	datasets.md §2.4
I4	test_round_trip_load_json_dumps_load	For every row in train/briefs.jsonl: row_dict_a = json.loads(line); line_b = canonical_dumps(row_dict_a); row_dict_b = json.loads(line_b); assert row_dict_a == row_dict_b AND line_b == line.rstrip("\n"). 15 000 rows checked; fails on first discrepancy.	datasets.md §3.1, §3.5 invariant #6
I5	test_verbatim_contamination_detector_sgd_mtop	Build corpus_snapshot_20260425 license cache (sqlite FTS5 over SGD + MTOP exports). For every seed_utterance in train/briefs.jsonl + val/briefs.jsonl, query the FTS5 index for a ≥ 10-token verbatim suffix match. Assert zero hits. Any hit → LicenseConflictError is raised by the CI wrapper.	datasets.md §3.4, §7 edge 3, §9.1
I6	test_loader_cross_consistency_templates_vs_drift_patterns	Load both libraries; assert every primary-domain pattern's mutation keys ⊆ union of drift_slot_tags across its domain's templates (the two transversal payment-auth patterns exempted).	datasets.md §3.5 invariant #4
I7	test_loader_cross_consistency_drifts_vs_api_schemas	For every pattern, from_version and to_version exist under data/api_schemas/<pattern.domain>/.	datasets.md §3.3
I8	test_eval_load_raises_on_catalogue_hash_mismatch	Publish a bundle with current catalogue; mutate drifts.yaml by one byte; invoke consumer-side load_briefs(path) → raises CatalogueHashMismatchError before any row is consumed.	datasets.md §3.5 invariant #9, §5
I9	test_sft_generator_restart_end_to_end	Generate 5 trajectories; kill -9 the process after row 3 (simulated via subprocess + signal.SIGKILL); restart; assert final file has 5 rows, a single shared generation_batch_id, generation_index == [0,1,2,3,4] strictly, and no PartialSFTCorpusError.	datasets.md §4.6, §7 edge 11
I10	test_bundle_immutability_after_publish	Publish v1.0; attempt to re-publish without changes; assert sha256(train/briefs.jsonl) matches v1.0. Mutate one byte in an authored template → re-publication fails CI with DatasetSchemaError (version bump required).	datasets.md §3.5 invariant #10, §2.4

Total integration tests: 10.

---

4. Coverage target

100% line + 95% branch on:

• driftcall/data/models.py (dataclass definitions — trivial to hit 100%)
• driftcall/data/loaders.py (every loader, every validation branch, every error raise)
• driftcall/data/errors.py (every DatasetError subclass constructed in at least one test)
• training/data_export.py (seed sampling, canonical dumps, write path, disjointness assertion)
• training/sft_generator.py (append + fsync, batch-id rehydration, partial-count validation, Sarvam-M error paths mocked)
• scripts/build_license_cache.py (FTS5 schema DDL, 5-gram tokenizer wiring, CI read-only guard)

Branch coverage ≥ 95% — every error-mode if / raise pair is exercised. The remaining 5% allowance covers unreachable else branches defensively guarding against enum exhaustion (Python has no exhaustive-match static guarantee).

Enforced by:

python3 -m pytest tests/data/ \
  --cov=driftcall.data \
  --cov=training.data_export \
  --cov=training.sft_generator \
  --cov=scripts.build_license_cache \
  --cov-branch \
  --cov-fail-under=100 \
  --cov-report=term-missing

Any PR that drops line coverage below 100% or branch coverage below 95% on these modules fails CI.

---

5. Fixtures

Fixtures live in DRIFTCALL/tests/data/conftest.py and are shared verbatim with evaluation_tests.md and training_tests.md. All fixtures are @pytest.fixture(scope="session") unless noted; they are pure-read and return frozen dataclasses or bytes.

5.1 brief_row_happy

A canonical Stage-2 airline-booking BriefRow with hinglish seed_utterance, drifted at turn 4 via airline.price_rename. Matches the JSONL example in datasets.md §8.5 exactly (its canonical_dumps(asdict(row)) equals the §8.5 golden line byte-for-byte). All three lineage hashes are pinned to the corpus_snapshot_20260425 fixture (§5.5).

5.2 brief_row_stage3_compound

A Stage-3 compound row (hotel + payment, bilingual code-switch between hi and en) with two drift events in drift_schedule — hotel.tnc_change at turn 3 and payment.auth_scope_upgrade at turn 6. Exercises the transversal-payment-auth-exempt branch of datasets.md §3.5 invariant #4.

5.3 manifest_ok

An AudioManifest built from 20 curated AudioClip rows (4 per language × 5 languages) pulled from IndicVoices-R — all source="real_indicvoices_r", every sha256 matching the on-disk WAV under tests/data/fixtures/audio/real/, every duration_s ≤ 20.0. Used to verify the happy-path of load_audio_manifest.

5.4 manifest_with_orphan

Same as manifest_ok but with one row whose path references kn/iv_r_kn_9999.wav (absent on disk). Drives the ChecksumMismatchError + DatasetFileMissingError error-mode tests.

5.5 corpus_snapshot_20260425

A byte-frozen snapshot of the entire data/ tree as of 2026-04-25 (publication seed date). Contains:

• templates.yaml + its pinned sha256
• i18n.yaml + its pinned sha256
• drifts.yaml + its pinned sha256
• All 14 api_schemas/*/*.json files
• The 20-row MANIFEST.jsonl
• License-cache sqlite files (.license_cache/sgd.idx, .license_cache/mtop.idx)
• Pinned Apache-2.0 LICENSE SHA constant (APACHE_2_0_CANONICAL_SHA)

Loaded once per session via pytest.fixture(scope="session"). Every lineage-hash test compares against constants frozen in this fixture, so a corpus-file byte mutation anywhere under data/ causes the hash-pinning tests (U13 – U17, U27) to fail loudly — the intended canary for silent catalogue drift.

This fixture is shared verbatim with:

• DRIFTCALL/docs/tests/evaluation_tests.md (consumer-side CatalogueHashMismatchError coverage)
• DRIFTCALL/docs/tests/training_tests.md (GRPO warmup corpus lineage, sft_warmup/ happy-path + restart coverage)

Authors of those test plans import via from tests.data.conftest import corpus_snapshot_20260425 rather than re-deriving snapshots — single source of truth prevents divergence.

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This test plan implements the full verification surface for docs/modules/datasets.md. It does not exist until ≥ 1 fresh critic returns NOTHING_FURTHER per CLAUDE.md §3.2 Batch D4. Fixtures are locked to corpus_snapshot_20260425 and shared with evaluation_tests.md + training_tests.md — any change here must be mirrored there in the same PR.