/*
 * Copyright 2018 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.BugCheckerRefactoringTestHelper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Tests for {@link SubstringOfZero}. */
@RunWith(JUnit4.class)
public class SubstringOfZeroTest {
  private final BugCheckerRefactoringTestHelper helper =
      BugCheckerRefactoringTestHelper.newInstance(SubstringOfZero.class, getClass());

  @Test
  public void positiveJustVars() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "hello";
                String y = x.substring(0);
              }
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "hello";
                String y = x;
              }
            }
            """)
        .doTest();
  }

  @Test
  public void positiveVarsWithMethods() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "HELLO";
                String y = x.toLowerCase().substring(0);
              }
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "HELLO";
                String y = x.toLowerCase();
              }
            }
            """)
        .doTest();
  }

  @Test
  public void negativeJustVarsOneArg() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "hello";
                String y = x.substring(1);
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void negativeJustVarsTwoArg() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "hello";
                String y = x.substring(1, 3);
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void negativeVarsWithMethodsOneArg() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "HELLO";
                String y = x.toLowerCase().substring(1);
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void negativeVarsWithMethodsTwoArg() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "HELLO";
                String y = x.toLowerCase().substring(1, 3);
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void negativeVarsWithDifferentMethod() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              void f() {
                String x = "HELLO";
                char y = x.charAt(0);
              }
            }
            """)
        .expectUnchanged()
        .doTest();
  }

  @Test
  public void positiveStringLiteral() {
    helper
        .addInputLines(
            "Test.java",
            """
            class Test {
              public static final int MY_CONSTANT = 0;

              void f() {
                String x = "hello".substring(MY_CONSTANT);
              }
            }
            """)
        .addOutputLines(
            "Test.java",
            """
            class Test {
              public static final int MY_CONSTANT = 0;

              void f() {
                String x = "hello";
              }
            }
            """)
        .doTest();
  }
}
