/*
 * Copyright 2017 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;

/** {@link LoopConditionChecker}Test */
@RunWith(JUnit4.class)
public class LoopConditionCheckerTest {

  private final CompilationTestHelper compilationTestHelper =
      CompilationTestHelper.newInstance(LoopConditionChecker.class, getClass());

  @Test
  public void positive() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              int h9() {
                int sum = 0;
                int i, j;
                for (i = 0; i < 10; ++i) {
                  // BUG: Diagnostic contains:
                  for (j = 0; j < 10; ++i) {
                    sum += j;
                  }
                }
                return sum;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void positive_noUpdate() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              void f() {
                // BUG: Diagnostic contains:
                for (int i = 0; i < 10; ) {}
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              int h9() {
                int sum = 0;
                int i, j;
                for (i = 0; i < 10; ++i) {
                  for (j = 0; j < 10; ++i) {
                    sum += j;
                    j++;
                  }
                }
                return sum;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_forExpression() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              void f() {
                for (int i = 0; i < 10; i++) {
                  System.err.println(i);
                }
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_noVariable() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            import java.util.Iterator;

            class Test {
              void f(Iterable<String> xs) {
                Iterator<String> it = xs.iterator();
                while (it.hasNext()) {
                  System.err.println(it.next());
                }
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_noCondition() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              void f() {
                for (; ; ) {}
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_noUpdate() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              void f() {
                for (int i = 0; i < 10; ) {
                  i++;
                }
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_conditionUpdate() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              void f() {
                int i = 0;
                while (i++ < 10) {}
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negative_field() {
    compilationTestHelper
        .addSourceLines(
            "Test.java",
            """
            class Test {
              int i = 0;

              void f() {
                while (i < 10) {
                  g();
                }
              }

              void g() {
                i++;
              }
            }
            """)
        .doTest();
  }
}
