code: /*
   * Copyright (c) 2022 Airbyte, Inc., all rights reserved.
   */
  
  package io.airbyte.db.jdbc.streaming;
  
  import static org.junit.jupiter.api.Assertions.*;
  
  import java.util.Optional;
  import org.junit.jupiter.api.Test;
  
  class InitialSizeEstimatorTest {
  
    @Test
    void testIt() {
      final long bufferByteSize = 120;
      final int initialSampleSize = 5;
      final int minFetchSize = 1;
      final int defaultFetchSize = 20;
      final int maxFetchSize = 120;
      final InitialSizeEstimator sizeEstimator = new InitialSizeEstimator(
          bufferByteSize,
          initialSampleSize,
          minFetchSize,
          defaultFetchSize,
          maxFetchSize);
  
      // size: 3 * 4 = 12
      sizeEstimator.accept("1");
      assertFalse(sizeEstimator.getFetchSize().isPresent());
      // size: 4 * 4 = 16
      sizeEstimator.accept("11");
      assertFalse(sizeEstimator.getFetchSize().isPresent());
      // size: 5 * 4 = 20
      sizeEstimator.accept("111");
      assertFalse(sizeEstimator.getFetchSize().isPresent());
      // size: 6 * 4 = 24
      sizeEstimator.accept("1111");
      assertFalse(sizeEstimator.getFetchSize().isPresent());
      // size: 7 * 4 = 28, fetch size is available
      sizeEstimator.accept("11111");
      final Optional<Integer> fetchSize = sizeEstimator.getFetchSize();
      assertTrue(fetchSize.isPresent());
      final long expectedMaxByteSize = 28L;
      assertEquals(expectedMaxByteSize, Math.round(sizeEstimator.getMaxRowByteSize()));
      assertEquals(bufferByteSize / expectedMaxByteSize, fetchSize.get().longValue());
    }
  
  }
  