/*
 * Copyright 2012 The Error Prone Authors.
 *
 * 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.errorprone.bugpatterns;

import com.google.errorprone.CompilationTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/**
 * @author cushon@google.com (Liam Miller-Cushon)
 */
@RunWith(JUnit4.class)
public class OptionalEqualityTest {

  private final CompilationTestHelper compilationHelper =
      CompilationTestHelper.newInstance(OptionalEquality.class, getClass());

  @Test
  public void positiveCase_equal() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Optional;

            class Test {
              boolean f(Optional<Integer> a, Optional<Integer> b) {
                // BUG: Diagnostic contains: a.equals(b)
                return a == b;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void positiveCase_notEqual() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Optional;

            class Test {
              boolean f(Optional<Integer> a, Optional<Integer> b) {
                // BUG: Diagnostic contains: !a.equals(b)
                return a != b;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negativeCase() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Optional;

            class Test {
              boolean f(Optional<Integer> b) {
                return b == null;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void maybeNull() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Optional;

            class Test {
              boolean f(Optional<Integer> a) {
                Optional<Integer> b = Optional.of(42);
                // BUG: Diagnostic contains: Did you mean 'return Objects.equals(a, b);' or 'return
                // a.equals(b);'?
                return a == b;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void maybeNull_prefersAlreadyImportedHelper() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Objects;
            import com.google.common.base.Optional;

            class Test {
              boolean f(Optional<Integer> a) {
                Optional<Integer> b = Optional.of(42);
                // BUG: Diagnostic contains: Did you mean 'return Objects.equal(a, b);' or 'return
                // a.equals(b);'?
                return a == b;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void definitelyNull() {
    compilationHelper
        .addSourceLines(
            "Test.java",
            """
            import com.google.common.base.Optional;

            class Test {
              boolean f() {
                Optional<Integer> a = null;
                Optional<Integer> b = Optional.of(42);
                // BUG: Diagnostic contains: Did you mean 'return Objects.equals(a, b);'?
                return a == b;
              }
            }
            """)
        .doTest();
  }
}
