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Utilities to help with writing tests for, or using, classes which use Pojomatic. This library includes classes with JUnit and TestNG style assertEquals methods which include differences (via Pojomatic.diff(Object, Object)) in the error message if the assertion fails.

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package org.pojomatic.test;

import org.pojomatic.Pojomatic;
import org.pojomatic.NoPojomaticPropertiesException;

/**
 * This class is not meant to be a part of the public API.
 */
public class AssertUtils {

  /**
   * Determines if two objects are both null or are equal according to
   * {@link Object#equals(Object)}.
   *
   * @param first the first object to compare
   * @param second the second object to compare
   * @return {@code true} if both objects are null,
   * or {@code first} is non-null and {@code first.equals(second)},
   * {@code false} otherwise
   * @see Object#equals(Object)
   */
  public static boolean equal(Object first, Object second) {
    return first == null ? second == null : first.equals(second);
  }

  /**
   * Asserts that two objects are either both null or are equal according to
   * {@link Object#equals(Object)}. If not, an {@code AssertionError} is thrown. If the objects are
   * not equal, but the types of two objects are compatible for equality, then the differences as
   * determined by {@link Pojomatic#diff(Object, Object)} are included in the failure message.
   *
   * @param message the message to add if the assertion fails
   * @param expected will be displayed first if the assertion fails
   * @param actual will be displayed second if the assertion fails
   * @throws AssertionError if the objects are not equal. {@link AssertionError#getMessage()} will
   * include information about the differences
   */
  public static void assertEquals(String message, Object expected, Object actual) {
    if (!equal(expected, actual)) {
      if (expected == null) {
        throw new AssertionError(
          makeBuilder(message).append("expected is null, but actual is ").append(actual));
      }
      if (actual == null) {
        throw new AssertionError(
          makeBuilder(message).append("actual is null, but expected is ").append(expected));
      }
      try {
        if (Pojomatic.areCompatibleForEquals(expected.getClass(), actual.getClass())) {
          throw new AssertionError(appendStandardEqualityMessage(
            makeBuilder(message).append("differences between expected and actual:")
            .append(Pojomatic.diff(expected, actual))
              .append(" ("), expected, actual).append(")").toString());
        }
      }
      catch (NoPojomaticPropertiesException e) {}
      throw new AssertionError(
        appendStandardEqualityMessage(makeBuilder(message), expected, actual).toString());
      }
  }

  private static StringBuilder appendStandardEqualityMessage(
    StringBuilder builder, Object expected, Object actual) {
    return builder
      .append("expected:<").append(expected).append("> but was:<").append(actual).append(">");
  }

  private static StringBuilder makeBuilder(String message) {
    return message == null ? new StringBuilder() : new StringBuilder(message).append(" ");
  }

  private AssertUtils() {}

}