package com.atlassian.plugin.util;
   
   import java.util.Arrays;
   import java.util.regex.Pattern;
   
   import org.junit.Test;
   
   import static org.hamcrest.MatcherAssert.assertThat;
   import static org.hamcrest.core.Is.is;
  
  public class TestRegularExpressions
  {
      @Test
      public void anyOfEmptyDoesntMatchAnything()
      {
          final String compound = RegularExpressions.anyOf(Arrays.<String>asList());
          final Pattern pattern = Pattern.compile(compound);
          assertThat(pattern.matcher("").matches(), is(false));
          assertThat(pattern.matcher("a").matches(), is(false));
          // Yes, the next few are a little whitebox, but they're designed to pick up likely implementation faults
          assertThat(pattern.matcher("a/A").matches(), is(false));
          assertThat(pattern.matcher("a\\A").matches(), is(false));
          assertThat(pattern.matcher("a\\\\A").matches(), is(false));
      }
  
      @Test
      public void anyOfOneMatchesIt()
      {
          final String compound = RegularExpressions.anyOf(Arrays.asList("a+"));
          final Pattern pattern = Pattern.compile(compound);
          assertThat(pattern.matcher("").matches(), is(false));
          assertThat(pattern.matcher("a").matches(), is(true));
          assertThat(pattern.matcher("aa").matches(), is(true));
          assertThat(pattern.matcher("b").matches(), is(false));
          assertThat(pattern.matcher("bb").matches(), is(false));
          assertThat(pattern.matcher("ab").matches(), is(false));
      }
  
      @Test
      public void anyOfTwoMatchesEither()
      {
          final String compound = RegularExpressions.anyOf(Arrays.asList("a+", "b+"));
          final Pattern pattern = Pattern.compile(compound);
          assertThat(pattern.matcher("").matches(), is(false));
          assertThat(pattern.matcher("a").matches(), is(true));
          assertThat(pattern.matcher("aa").matches(), is(true));
          assertThat(pattern.matcher("b").matches(), is(true));
          assertThat(pattern.matcher("bb").matches(), is(true));
          assertThat(pattern.matcher("ab").matches(), is(false));
          assertThat(pattern.matcher("c").matches(), is(false));
          assertThat(pattern.matcher("cc").matches(), is(false));
      }
  
      @Test
      public void anyOfWithOverlap()
      {
          final String compound = RegularExpressions.anyOf(Arrays.asList("a(a|b)+b", "a(a|b)+b"));
          final Pattern pattern = Pattern.compile(compound);
          assertThat(pattern.matcher("").matches(), is(false));
          assertThat(pattern.matcher("ab").matches(), is(false));
          assertThat(pattern.matcher("aab").matches(), is(true));
          assertThat(pattern.matcher("abb").matches(), is(true));
          assertThat(pattern.matcher("acb").matches(), is(false));
      }
  
  
      @Test
      public void naiveComplexExample()
      {
          final String compound = RegularExpressions.anyOf(Arrays.asList("ab", "c(d|e)f", "gh*g+"));
          final Pattern pattern = Pattern.compile(compound);
          assertThat(pattern.matcher("").matches(), is(false));
          assertThat(pattern.matcher("a").matches(), is(false));
          assertThat(pattern.matcher("ab").matches(), is(true));
          assertThat(pattern.matcher("cf").matches(), is(false));
          assertThat(pattern.matcher("cdf").matches(), is(true));
          assertThat(pattern.matcher("cef").matches(), is(true));
          assertThat(pattern.matcher("cdef").matches(), is(false));
          assertThat(pattern.matcher("g").matches(), is(false));
          assertThat(pattern.matcher("gg").matches(), is(true));
          assertThat(pattern.matcher("ghg").matches(), is(true));
          assertThat(pattern.matcher("ghgh").matches(), is(false));
      }
  }