c_glib/test/test-array-statistics.rb

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#
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class TestArrayStatistics < Test::Unit::TestCase
  include Helper::Buildable

  def setup
    omit("Parquet is required") unless defined?(::Parquet)

    Tempfile.create(["data", ".parquet"]) do |file|
      @file = file
      array = build_int64_array([nil, -(2 ** 32), 2 ** 32])
      @table = build_table("int64" => array)
      writer = Parquet::ArrowFileWriter.new(@table.schema, @file.path)
      chunk_size = 1024
      writer.write_table(@table, chunk_size)
      writer.close
      reader = Parquet::ArrowFileReader.new(@file.path)
      begin
        @statistics = reader.read_table.get_column_data(0).get_chunk(0).statistics
        yield
      ensure
        reader.unref
      end
    end
  end

  test("#has_null_count?") do
    assert do
      @statistics.has_null_count?
    end
  end

  test("#null_count_exact?") do
    assert do
      @statistics.null_count_exact?
    end
  end

  test("#null_count_exact") do
    assert_equal(1, @statistics.null_count_exact)
  end

  test("#null_count_approximate") do
    assert do
      @statistics.null_count_approximate.nan?
    end
  end

  test("#has_distinct_count?") do
    assert do
      not @statistics.has_distinct_count?
    end
  end

  test("#distinct_count_exact?") do
    assert do
      not @statistics.distinct_count_exact?
    end
  end

  test ("#distinct_count_exact") do
    assert_equal(-1, @statistics.distinct_count_exact)
  end

  test ("#distinct_count_approximate") do
    assert do
      @statistics.distinct_count_approximate.nan?
    end
  end
end