Time Travel Read test

[wjones127]

Correctly resolving time travel is an important part of Delta Lake. One way to test that is to add additional parquet files to the expected data. Ones that aren't the current version could have files names such as expected_data_{i}.parquet where {i} is the Delta table version number.

[scottsand-db]

└── reference_tables
    ├── reference_table_1
    │   |── delta
    │   │   └── a.parquet
    │   │   └── b.parquet
    │   │   └── c.parquet
    │   │   └── _delta_log
    │   ├── latest
    │   │   └── a.parquet
    │   │   └── b.parquet
    │   │   └── c.parquet
    │   ├── v0
    │   │   └── a.parquet
    │   └── v1
    │   │   └── a.parquet
    │   │   └── b.parquet
    └── reference_table_2

[wjones127]

latest expected table is required, versions ones (v1) are optional.

/reference_tables
  /reference_table_1
    /delta
      /_delta_log
      parquet
    /expected
      /latest
        parquet
      /v1
        parquet