OptionalDoubleSubject.java

/*
 * Copyright (c) 2016 Google, Inc.
 *
 * Licensed 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 com.google.common.truth;

import java.util.OptionalDouble;
import javax.annotation.Nullable;

/**
 * Propositions for Java 8 {@link OptionalDouble} subjects.
 *
 * @author Ben Douglass
 */
public final class OptionalDoubleSubject extends Subject<OptionalDoubleSubject, OptionalDouble> {

  OptionalDoubleSubject(FailureStrategy failureStrategy, @Nullable OptionalDouble subject) {
    super(failureStrategy, subject);
  }

  /** Fails if the {@link OptionalDouble} is empty or the subject is null. */
  public void isPresent() {
    if (actual() == null || !actual().isPresent()) {
      failWithoutActual("is present");
    }
  }

  /** Fails if the {@link OptionalDouble} is present or the subject is null. */
  public void isEmpty() {
    if (actual() == null || actual().isPresent()) {
      fail("is empty");
    }
  }

  /**
   * Fails if the {@link OptionalDouble} does not have the given value or the subject is null. This
   * method is <i>not</i> recommended when the code under test is doing any kind of arithmetic,
   * since the exact result of floating point arithmetic is sensitive to apparently trivial changes.
   * More sophisticated comparisons can be done using {@link #hasValueThat()}. This method is
   * recommended when the code under test is specified as either copying a value without
   * modification from its input or returning a well-defined literal or constant value.
   */
  public void hasValue(double expected) {
    if (actual() == null || !actual().isPresent()) {
      fail("has value", expected);
    } else {
      double actual = actual().getAsDouble();
      if (actual != expected) {
        fail("has value", expected);
      }
    }
  }

  /**
   * Prepares for a check regarding the value contained within the {@link OptionalDouble}. Fails
   * immediately if the subject is empty.
   */
  public DoubleSubject hasValueThat() {
    if (actual() == null || !actual().isPresent()) {
      failWithoutActual("is present");
      return ignoreCheck().that(0.0);
    } else {
      return check().that(actual().getAsDouble());
    }
  }

  private static final SubjectFactory<OptionalDoubleSubject, OptionalDouble> FACTORY =
      new SubjectFactory<OptionalDoubleSubject, OptionalDouble>() {
        @Override
        public OptionalDoubleSubject getSubject(FailureStrategy fs, OptionalDouble target) {
          return new OptionalDoubleSubject(fs, target);
        }
      };

  public static SubjectFactory<OptionalDoubleSubject, OptionalDouble> optionalDoubles() {
    return FACTORY;
  }
}