python/tests/test_substrait.py

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import pyarrow as pa
import pytest
from datafusion import SessionContext
from datafusion import substrait as ss


@pytest.fixture
def ctx():
    return SessionContext()


def test_substrait_serialization(ctx):
    batch = pa.RecordBatch.from_arrays(
        [pa.array([1, 2, 3]), pa.array([4, 5, 6])],
        names=["a", "b"],
    )

    ctx.register_record_batches("t", [[batch]])

    assert ctx.catalog().schema().names() == {"t"}

    # For now just make sure the method calls blow up
    substrait_plan = ss.Serde.serialize_to_plan("SELECT * FROM t", ctx)
    substrait_bytes = substrait_plan.encode()
    assert isinstance(substrait_bytes, bytes)
    substrait_bytes = ss.Serde.serialize_bytes("SELECT * FROM t", ctx)
    substrait_plan = ss.Serde.deserialize_bytes(substrait_bytes)
    logical_plan = ss.Consumer.from_substrait_plan(ctx, substrait_plan)

    # demonstrate how to create a DataFrame from a deserialized logical plan
    df = ctx.create_dataframe_from_logical_plan(logical_plan)

    substrait_plan = ss.Producer.to_substrait_plan(df.logical_plan(), ctx)


@pytest.mark.parametrize("path_to_str", [True, False])
def test_substrait_file_serialization(ctx, tmp_path, path_to_str):
    batch = pa.RecordBatch.from_arrays(
        [pa.array([1, 2, 3]), pa.array([4, 5, 6])],
        names=["a", "b"],
    )

    ctx.register_record_batches("t", [[batch]])

    assert ctx.catalog().schema().names() == {"t"}

    path = tmp_path / "substrait_plan"
    path = str(path) if path_to_str else path

    sql_command = "SELECT * FROM T"
    ss.Serde.serialize(sql_command, ctx, path)

    expected_plan = ss.Serde.serialize_to_plan(sql_command, ctx)
    actual_plan = ss.Serde.deserialize(path)

    expected_logical_plan = ss.Consumer.from_substrait_plan(ctx, expected_plan)
    expected_actual_plan = ss.Consumer.from_substrait_plan(ctx, actual_plan)

    assert str(expected_logical_plan) == str(expected_actual_plan)


def test_json_processing_round_trip(ctx: SessionContext):
    ctx.register_record_batches("t", [[pa.record_batch({"a": [1]})]])
    original_logical_plan = ctx.sql("SELECT * FROM t").logical_plan()

    substrait_plan = ss.Producer.to_substrait_plan(original_logical_plan, ctx)
    json_plan = substrait_plan.to_json()

    expected = """\
  "relations": [
    {
      "root": {
        "input": {
          "project": {
            "common": {
              "emit": {
                "outputMapping": [
                  1
                ]
              }
            },
            "input": {
              "read": {
                "baseSchema": {
                  "names": [
                    "a"
                  ],
                  "struct": {
                    "types": [
                      {
                        "i64": {
                          "nullability": "NULLABILITY_NULLABLE"
                        }
                      }
                    ],
                    "nullability": "NULLABILITY_REQUIRED"
                  }
                },
                "namedTable": {
                  "names": [
                    "t"
                  ]
                }
              }
            },
            "expressions": [
              {
                "selection": {
                  "directReference": {
                    "structField": {}
                  },
                  "rootReference": {}
                }
              }
            ]
          }
        },
        "names": [
          "a"
        ]
      }
    }
  ]"""

    assert expected in json_plan

    round_trip_substrait_plan = ss.Plan.from_json(json_plan)
    round_trip_logical_plan = ss.Consumer.from_substrait_plan(
        ctx, round_trip_substrait_plan
    )

    assert round_trip_logical_plan == original_logical_plan