content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.beam.sdk.io.range;
  
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.closeTo;
  import static org.hamcrest.Matchers.containsString;
  import static org.hamcrest.Matchers.greaterThanOrEqualTo;
  
  import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
  import org.junit.Test;
  import org.junit.runner.RunWith;
  import org.junit.runners.Parameterized;
  import org.junit.runners.Parameterized.Parameter;
  import org.junit.runners.Parameterized.Parameters;
  
  /**
   * Combinatorial tests for {@link ByteKeyRange#interpolateKey}, which also checks {@link
   * ByteKeyRange#estimateFractionForKey} by converting the interpolated keys back to fractions.
   */
  @RunWith(Parameterized.class)
  public class ByteKeyRangeInterpolateKeyTest {
    private static final ByteKey[] TEST_KEYS = ByteKeyRangeTest.RANGE_TEST_KEYS;
  
    @Parameters(name = "{index}: {0}")
    public static Iterable<Object[]> data() {
      ImmutableList.Builder<Object[]> ret = ImmutableList.builder();
      for (int i = 0; i < TEST_KEYS.length; ++i) {
        for (int j = i + 1; j < TEST_KEYS.length; ++j) {
          ret.add(new Object[] {ByteKeyRange.of(TEST_KEYS[i], TEST_KEYS[j])});
        }
      }
      return ret.build();
    }
  
    @Parameter public ByteKeyRange range;
  
    @Test
    public void testInterpolateKeyAndEstimateFraction() {
      double delta = 0.0000001;
      double[] testFractions =
          new double[] {0.01, 0.1, 0.123, 0.2, 0.3, 0.45738, 0.5, 0.6, 0.7182, 0.8, 0.95, 0.97, 0.99};
      ByteKey last = range.getStartKey();
      for (double fraction : testFractions) {
        String message = Double.toString(fraction);
        try {
          ByteKey key = range.interpolateKey(fraction);
          assertThat(message, key, greaterThanOrEqualTo(last));
          assertThat(message, range.estimateFractionForKey(key), closeTo(fraction, delta));
          last = key;
        } catch (IllegalStateException e) {
          assertThat(message, e.getMessage(), containsString("near-empty ByteKeyRange"));
        }
      }
    }
  }
  