ruby/red-parquet/test/test-array-statistics.rb

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class TestArrayStatistics < Test::Unit::TestCase
  def setup
    data = Tempfile.create(["red-parquet", ".parquet"]) do |file|
      table = Arrow::Table.new(int64: [nil, -(2 ** 32), 2 ** 32])
      table.save(file)
      File.read(file, mode: "rb")
    end
    loaded_table = Arrow::Table.load(Arrow::Buffer.new(data),
                                     format: :parquet)
    @statistics = loaded_table[:int64].data.chunks[0].statistics
  end

  def test_null_count
    assert do
      @statistics.has_null_count?
    end
    assert do
      @statistics.null_count_exact?
    end
    assert_equal(1, @statistics.null_count)
  end

  def test_distinct_count
    assert do
      not @statistics.has_distinct_count?
    end
    assert do
      not @statistics.distinct_count_exact?
    end
    assert_nil(@statistics.distinct_count)
  end
end