/*
    * Copyright (C) 2010 The Guava 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.common.base;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.annotations.GwtIncompatible;
  import com.google.common.testing.NullPointerTester;
  
  import junit.framework.TestCase;
  
  /**
   * Unit test for {@link Strings}.
   *
   * @author Kevin Bourrillion
   */
  @GwtCompatible(emulated = true)
  public class StringsTest extends TestCase {
    public void testNullToEmpty() {
      assertEquals("", Strings.nullToEmpty(null));
      assertEquals("", Strings.nullToEmpty(""));
      assertEquals("a", Strings.nullToEmpty("a"));
    }
  
    public void testEmptyToNull() {
      assertNull(Strings.emptyToNull(null));
      assertNull(Strings.emptyToNull(""));
      assertEquals("a", Strings.emptyToNull("a"));
    }
  
    public void testIsNullOrEmpty() {
      assertTrue(Strings.isNullOrEmpty(null));
      assertTrue(Strings.isNullOrEmpty(""));
      assertFalse(Strings.isNullOrEmpty("a"));
    }
  
    public void testPadStart_noPadding() {
      assertSame("", Strings.padStart("", 0, '-'));
      assertSame("x", Strings.padStart("x", 0, '-'));
      assertSame("x", Strings.padStart("x", 1, '-'));
      assertSame("xx", Strings.padStart("xx", 0, '-'));
      assertSame("xx", Strings.padStart("xx", 2, '-'));
    }
  
    public void testPadStart_somePadding() {
      assertEquals("-", Strings.padStart("", 1, '-'));
      assertEquals("--", Strings.padStart("", 2, '-'));
      assertEquals("-x", Strings.padStart("x", 2, '-'));
      assertEquals("--x", Strings.padStart("x", 3, '-'));
      assertEquals("-xx", Strings.padStart("xx", 3, '-'));
    }
  
    public void testPadStart_negativeMinLength() {
      assertSame("x", Strings.padStart("x", -1, '-'));
    }
  
    // TODO: could remove if we got NPT working in GWT somehow
    public void testPadStart_null() {
      try {
        Strings.padStart(null, 5, '0');
        fail();
      } catch (NullPointerException expected) {
      }
    }
  
    public void testPadEnd_noPadding() {
      assertSame("", Strings.padEnd("", 0, '-'));
      assertSame("x", Strings.padEnd("x", 0, '-'));
      assertSame("x", Strings.padEnd("x", 1, '-'));
      assertSame("xx", Strings.padEnd("xx", 0, '-'));
      assertSame("xx", Strings.padEnd("xx", 2, '-'));
    }
  
    public void testPadEnd_somePadding() {
      assertEquals("-", Strings.padEnd("", 1, '-'));
      assertEquals("--", Strings.padEnd("", 2, '-'));
      assertEquals("x-", Strings.padEnd("x", 2, '-'));
      assertEquals("x--", Strings.padEnd("x", 3, '-'));
      assertEquals("xx-", Strings.padEnd("xx", 3, '-'));
    }
  
    public void testPadEnd_negativeMinLength() {
      assertSame("x", Strings.padEnd("x", -1, '-'));
    }
  
    // TODO: could remove if we got NPT working in GWT somehow
   public void testPadEnd_null() {
     try {
       Strings.padEnd(null, 5, '0');
       fail();
     } catch (NullPointerException expected) {
     }
   }
 
   public void testRepeat() {
     String input = "20";
     assertEquals("", Strings.repeat(input, 0));
     assertEquals("20", Strings.repeat(input, 1));
     assertEquals("2020", Strings.repeat(input, 2));
     assertEquals("202020", Strings.repeat(input, 3));
 
     assertEquals("", Strings.repeat("", 4));
 
     for (int i = 0; i < 100; ++i) {
       assertEquals(2 * i, Strings.repeat(input, i).length());
     }
 
     try {
       Strings.repeat("x", -1);
       fail();
     } catch (IllegalArgumentException expected) {
     }
     try {
       // Massive string
       Strings.repeat("12345678", (1 << 30) + 3);
       fail();
     } catch (ArrayIndexOutOfBoundsException expected) {
     }
   }
 
   // TODO: could remove if we got NPT working in GWT somehow
   public void testRepeat_null() {
     try {
       Strings.repeat(null, 5);
       fail();
     } catch (NullPointerException expected) {
     }
   }
 
   public void testCommonPrefix() {
     assertEquals("", Strings.commonPrefix("", ""));
     assertEquals("", Strings.commonPrefix("abc", ""));
     assertEquals("", Strings.commonPrefix("", "abc"));
     assertEquals("", Strings.commonPrefix("abcde", "xyz"));
     assertEquals("", Strings.commonPrefix("xyz", "abcde"));
     assertEquals("", Strings.commonPrefix("xyz", "abcxyz"));
     assertEquals("a", Strings.commonPrefix("abc", "aaaaa"));
     assertEquals("aa", Strings.commonPrefix("aa", "aaaaa"));
     assertEquals("abc",
         Strings.commonPrefix(new StringBuffer("abcdef"), "abcxyz"));
 
     // Identical valid surrogate pairs.
     assertEquals("abc\uD8AB\uDCAB",
         Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCABxyz"));
     // Differing valid surrogate pairs.
     assertEquals("abc",
         Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uDCACxyz"));
     // One invalid pair.
     assertEquals("abc",
         Strings.commonPrefix("abc\uD8AB\uDCABdef", "abc\uD8AB\uD8ABxyz"));
     // Two identical invalid pairs.
     assertEquals("abc\uD8AB\uD8AC",
         Strings.commonPrefix("abc\uD8AB\uD8ACdef", "abc\uD8AB\uD8ACxyz"));
     // Two differing invalid pairs.
     assertEquals("abc\uD8AB",
         Strings.commonPrefix("abc\uD8AB\uD8ABdef", "abc\uD8AB\uD8ACxyz"));
     // One orphan high surrogate.
     assertEquals("", Strings.commonPrefix("\uD8AB\uDCAB", "\uD8AB"));
     // Two orphan high surrogates.
     assertEquals("\uD8AB", Strings.commonPrefix("\uD8AB", "\uD8AB"));
   }
 
   public void testCommonSuffix() {
     assertEquals("", Strings.commonSuffix("", ""));
     assertEquals("", Strings.commonSuffix("abc", ""));
     assertEquals("", Strings.commonSuffix("", "abc"));
     assertEquals("", Strings.commonSuffix("abcde", "xyz"));
     assertEquals("", Strings.commonSuffix("xyz", "abcde"));
     assertEquals("", Strings.commonSuffix("xyz", "xyzabc"));
     assertEquals("c", Strings.commonSuffix("abc", "ccccc"));
     assertEquals("aa", Strings.commonSuffix("aa", "aaaaa"));
     assertEquals("abc",
         Strings.commonSuffix(new StringBuffer("xyzabc"), "xxxabc"));
 
     // Identical valid surrogate pairs.
     assertEquals("\uD8AB\uDCABdef",
         Strings.commonSuffix("abc\uD8AB\uDCABdef", "xyz\uD8AB\uDCABdef"));
     // Differing valid surrogate pairs.
     assertEquals("def",
         Strings.commonSuffix("abc\uD8AB\uDCABdef", "abc\uD8AC\uDCABdef"));
     // One invalid pair.
     assertEquals("def",
         Strings.commonSuffix("abc\uD8AB\uDCABdef", "xyz\uDCAB\uDCABdef"));
     // Two identical invalid pairs.
     assertEquals("\uD8AB\uD8ABdef",
         Strings.commonSuffix("abc\uD8AB\uD8ABdef", "xyz\uD8AB\uD8ABdef"));
     // Two differing invalid pairs.
     assertEquals("\uDCABdef",
         Strings.commonSuffix("abc\uDCAB\uDCABdef", "abc\uDCAC\uDCABdef"));
     // One orphan low surrogate.
     assertEquals("", Strings.commonSuffix("x\uD8AB\uDCAB", "\uDCAB"));
     // Two orphan low surrogates.
     assertEquals("\uDCAB", Strings.commonSuffix("\uDCAB", "\uDCAB"));
   }
 
   public void testValidSurrogatePairAt() {
     assertTrue(Strings.validSurrogatePairAt("\uD8AB\uDCAB", 0));
     assertTrue(Strings.validSurrogatePairAt("abc\uD8AB\uDCAB", 3));
     assertTrue(Strings.validSurrogatePairAt("abc\uD8AB\uDCABxyz", 3));
     assertFalse(Strings.validSurrogatePairAt("\uD8AB\uD8AB", 0));
     assertFalse(Strings.validSurrogatePairAt("\uDCAB\uDCAB", 0));
     assertFalse(Strings.validSurrogatePairAt("\uD8AB\uDCAB", -1));
     assertFalse(Strings.validSurrogatePairAt("\uD8AB\uDCAB", 1));
     assertFalse(Strings.validSurrogatePairAt("\uD8AB\uDCAB", -2));
     assertFalse(Strings.validSurrogatePairAt("\uD8AB\uDCAB", 2));
     assertFalse(Strings.validSurrogatePairAt("x\uDCAB", 0));
     assertFalse(Strings.validSurrogatePairAt("\uD8ABx", 0));
   }
 
   @GwtIncompatible("NullPointerTester")
   public void testNullPointers() {
     NullPointerTester tester = new NullPointerTester();
     tester.testAllPublicStaticMethods(Strings.class);
   }
 }