test: add Data Acceptance Tests (#909)

# Description
The description of the main changes of your pull request

# Related Issue(s)

- closes #864 

# Documentation

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.github/workflows/python_build.yml

@@ -102,7 +102,10 @@ jobs:
           pip install virtualenv
           virtualenv venv
           source venv/bin/activate
-          make develop
+          make develop      
+              
+      - name: Download Data Acceptance Tests (DAT) files
+        run: make setup-dat
 
       - name: Run tests
         run: |

python/.gitignore

@@ -15,3 +15,6 @@ __pycache__/
 docs/build
 
 *.so
+
+# dat data
+dat-data

python/Makefile

@@ -3,6 +3,7 @@
 VENV := venv
 MATURIN_VERSION := $(shell grep 'requires =' pyproject.toml | cut -d= -f2- | tr -d '[ "]')
 PACKAGE_VERSION := $(shell grep version Cargo.toml | head -n 1 | awk '{print $$3}' | tr -d '"' )
+DAT_VERSION := 0.0.2
 
 .PHONY: setup-venv
 setup-venv: ## Setup the virtualenv
@@ -14,6 +15,16 @@ setup: ## Setup the requirements
 	$(info --- Setup dependencies ---)
 	pip install "$(MATURIN_VERSION)"
 
+.PHONY: setup-dat
+setup-dat: ## Download DAT test files
+	mkdir -p dat-data
+	rm -rf dat-data/v$(DAT_VERSION)
+	curl -L --silent --output dat-data/deltalake-dat-v$(DAT_VERSION).tar.gz \
+		https://github.com/delta-incubator/dat/releases/download/v$(DAT_VERSION)/deltalake-dat-v$(DAT_VERSION).tar.gz 
+	tar --no-same-permissions -xzf dat-data/deltalake-dat-v$(DAT_VERSION).tar.gz
+	mv out dat-data/v$(DAT_VERSION)
+	rm dat-data/deltalake-dat-v$(DAT_VERSION).tar.gz
+
 .PHONY: build
 build: setup ## Build Python binding of delta-rs
 	$(info --- Build Python binding ---)

python/tests/data_acceptance/test_reader.py

@@ -0,0 +1,91 @@
+import json
+from pathlib import Path
+from typing import Any, Dict, NamedTuple, Optional
+
+import pyarrow as pa
+import pyarrow.parquet as pq
+import pytest
+
+from deltalake import DeltaTable
+
+
+class ReadCase(NamedTuple):
+    root: Path
+    version: Optional[int]
+    case_info: Dict[str, Any]
+    version_metadata: Dict[str, Any]
+
+
+cases = []
+
+dat_version = "0.0.2"
+reader_case_path = Path("dat-data") / f"v{dat_version}" / "reader_tests" / "generated"
+
+if not reader_case_path.exists():
+    pytest.skip(
+        "DAT test data not present. Run make setup-dat to download them.",
+        allow_module_level=True,
+    )
+
+for path in reader_case_path.iterdir():
+    if path.is_dir():
+        with open(path / "test_case_info.json") as f:
+            metadata = json.load(f)
+
+        for version_path in (path / "expected").iterdir():
+            if path.name.startswith("v"):
+                version = int(path.name[1:])
+            else:
+                version = None
+            with open(version_path / "table_version_metadata.json") as f:
+                version_metadata = json.load(f)
+
+        cases.append(ReadCase(path, version, metadata, version_metadata))
+
+failing_cases = {
+    "multi_partitioned_2": "Waiting for PyArrow 11.0.0 for decimal cast support (#1078)",
+    "nested_types": "Waiting for PyArrow 11.0.0 so we can ignore internal field names in equality",
+    "multi_partitioned": "Escaped characters in data file paths aren't yet handled (#1079)",
+    "no_stats": "We don't yet support files without stats (#582)",
+}
+
+
+@pytest.mark.parametrize(
+    "case", cases, ids=lambda case: f"{case.case_info['name']} (version={case.version})"
+)
+def test_dat(case: ReadCase):
+    root, version, case_info, version_metadata = case
+
+    if case_info["name"] in failing_cases:
+        msg = failing_cases[case_info["name"]]
+        pytest.skip(msg)
+
+    # Get Delta Table path
+    delta_root = root / "delta"
+
+    # Load table
+    dt = DeltaTable(str(delta_root), version=version)
+
+    # Compare protocol versions
+    assert dt.protocol().min_reader_version == version_metadata["min_reader_version"]
+    assert dt.protocol().min_writer_version == version_metadata["min_writer_version"]
+
+    # If supported protocol version, try to read, load parquet, and compare
+    if dt.protocol().min_reader_version <= 1:
+        version_path = "latest" if version is None else f"v{version}"
+        parquet_root = root / "expected" / version_path / "table_content"
+        expected = pq.read_table(parquet_root, coerce_int96_timestamp_unit="us")
+        actual = dt.to_pyarrow_table()
+        assert_tables_equal(expected, actual)
+    else:
+        # We should raise an error when attempting to read too advanced protocol
+        with pytest.raises(Exception):
+            dt.to_pyarrow_table()
+
+
+def assert_tables_equal(first: pa.Table, second: pa.Table) -> None:
+    assert first.schema == second.schema
+    sort_keys = [(col, "ascending") for col in first.column_names]
+    first_sorted = first.sort_by(sort_keys)
+    second_sorted = second.sort_by(sort_keys)
+    assert first_sorted == second_sorted