View difference between Paste ID: vCn6rydF and 9zWX8baH

 // Author: Ronen Schaffer
 import static org.junit.Assert.*;
 
 import org.junit.Test;
 
 public class StringListTests {
 
 	@Test
 	public void tests_from_example() {
 		// Arrange
 		StringList s = new StringList("abcae");
 
 		// Act
 
 		// Assert
 		assertEquals(5, s.length());
 		assertEquals('b', s.charAt(1));
 		assertEquals(0, s.indexOf('a'));
 		assertEquals(3, s.indexOf('a', 2));
 		assertEquals(-1, s.indexOf('d'));
 		assertTrue(s.compareTo(new StringList("abcde")) < 0);
 	}
 
 	@Test
 	public void StringListString_null_ShouldCreateEmptyString() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList((String) null);
 
 		// Assert
 		assertEquals("", sl.toString());
 	}
 
 	@Test
 	public void StringListString_EmptyString_ShouldCreateEmptyString() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList("");
 
 		// Assert
 		assertEquals("", sl.toString());
 	}
 
 	@Test
 	public void StringListString_a() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList("a");
 
 		// Assert
 		assertEquals("a", sl.toString());
 	}
 
 	@Test
 	public void StringListString_aa() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList("aa");
 
 		// Assert
 		assertEquals("aa", sl.toString());
 	}
 
 	@Test
 	public void StringListString_aab() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList("aab");
 
 		// Assert
 		assertEquals("aab", sl.toString());
 	}
 
 	@Test
 	public void StringListString_aabb() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList("aabb");
 
 		// Assert
 		assertEquals("aabb", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_null_ShouldCreateEmptyString() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList((StringList) null);
 
 		// Assert
 		assertEquals("", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_EmptyStringList_ShouldCreateEmptyString() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList(new StringList());
 
 		// Assert
 		assertEquals("", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_a() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList(new StringList("a"));
 
 		// Assert
 		assertEquals("a", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_aa() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList(new StringList("aa"));
 
 		// Assert
 		assertEquals("aa", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_aab() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList(new StringList("aab"));
 
 		// Assert
 		assertEquals("aab", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_aabb() {
 		// Arrange
 
 		// Act
 		StringList sl = new StringList(new StringList("aabb"));
 
 		// Assert
 		assertEquals("aabb", sl.toString());
 	}
 
 	@Test
 	public void StringListStringList_aabb_CheckAliasing() {
 		// Arrange
 		StringList src = new StringList("aabb");
 
 		// Act
 		StringList sl = new StringList(src);
 		src.concat(new StringList("c"));
 
 		// Assert
 		assertEquals("aabb", sl.toString());
 	}
 
 	@Test
 	public void charAt_a_0_ShouldReturn_a() {
 		// Arrange
 		StringList sl = new StringList("a");
 
 		// Act
 		int res = sl.charAt(0);
 
 		// Assert
 		assertEquals('a', res);
 	}
 
 	@Test
 	public void charAt_aa_1_ShouldReturn_a() {
 		// Arrange
 		StringList sl = new StringList("aa");
 
 		// Act
 		int res = sl.charAt(1);
 
 		// Assert
 		assertEquals('a', res);
 	}
 
 	@Test
 	public void charAt_aab_2_ShouldReturn_b() {
 		// Arrange
 		StringList sl = new StringList("aab");
 
 		// Act
 		int res = sl.charAt(2);
 
 		// Assert
 		assertEquals('b', res);
 	}
 
 	@Test
 	public void charAt_aabb_3_ShouldReturn_b() {
 		// Arrange
 		StringList sl = new StringList("aabb");
 
 		// Act
 		int res = sl.charAt(3);
 
 		// Assert
 		assertEquals('b', res);
 	}
 
 	@Test
 	public void concat_a_null_ShouldReturn_a() {
 		// Arrange
 		StringList sl1 = new StringList("a");
 		StringList sl2 = null;
 
 		// Act
 		StringList res = sl1.concat(sl2);
 
 		// Assert
 		assertEquals("a", res.toString());
 	}
 
 	@Test
 	public void concat_a_EmptyStringList_ShouldReturn_a() {
 		// Arrange
 		StringList sl1 = new StringList("a");
 		StringList sl2 = new StringList();
 
 		// Act
 		StringList res = sl1.concat(sl2);
 
 		// Assert
 		assertEquals("a", res.toString());
 	}
 
 	@Test
 	public void concat_EmptyStringList_a_ShouldReturn_a() {
 		// Arrange
 		StringList sl1 = new StringList();
 		StringList sl2 = new StringList("a");
 
 		// Act
 		StringList res = sl1.concat(sl2);
 
 		// Assert
 		assertEquals("a", res.toString());
 	}
 
 	@Test
 	public void concat_a_a_ShouldReturn_aa() {
 		// Arrange
 		StringList sl1 = new StringList("a");
 		StringList sl2 = new StringList("a");
 
 		// Act
 		StringList res = sl1.concat(sl2);
 
 		// Assert
 		assertEquals("aa", res.toString());
 	}
 
 	@Test
 	public void concat_abc_def_ShouldReturn_abcdef() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("def");
 
 		// Act
 		StringList res = sl1.concat(sl2);
 
 		// Assert
 		assertEquals("abcdef", res.toString());
 	}
 
 	@Test
 	public void concat_abc_def_CheckAliasing_ShouldReturn_abcdef() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("def");
 
 		// Act
 		StringList res1 = sl1.concat(sl2);
 		StringList res2 = sl1.concat(new StringList("ghi"));
 		StringList res3 = sl2.concat(new StringList("jkl"));
 		StringList res4 = sl2.concat(sl1);
 
 		// Assert
 		assertEquals("abcdef", res1.toString());
 		assertEquals("abcghi", res2.toString());
 		assertEquals("defjkl", res3.toString());
 		assertEquals("defabc", res4.toString());
 	}
 
 	@Test
 	public void indexOf_a_a_ShouldReturn0() {
 		// Arrange
 		StringList sl = new StringList("a");
 
 		// Act
 		int res = sl.indexOf('a');
 
 		// Assert
 		assertEquals(0, res);
 	}
 
 	@Test
 	public void indexOf_abc_a_ShouldReturn0() {
 		// Arrange
 		StringList sl = new StringList("abc");
 
 		// Act
 		int res = sl.indexOf('a');
 
 		// Assert
 		assertEquals(0, res);
 	}
 
 	@Test
 	public void indexOf_aaa_a_ShouldReturn0() {
 		// Arrange
 		StringList sl = new StringList("aaa");
 
 		// Act
 		int res = sl.indexOf('a');
 
 		// Assert
 		assertEquals(0, res);
 	}
 
 	@Test
 	public void indexOf_aaabccd_e_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList("aaabccd");
 
 		// Act
 		int res = sl.indexOf('e');
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	public void indexOf_aaa_a_1_ShouldReturn1() {
 		// Arrange
 		StringList sl = new StringList("aaa");
 
 		// Act
 		int res = sl.indexOf('a', 1);
 
 		// Assert
 		assertEquals(1, res);
 	}
 
 	@Test
 	public void indexOf_aabbccddd_b_ShouldReturn2() {
 		// Arrange
 		StringList sl = new StringList("aabbccddd");
 
 		// Act
 		int res = sl.indexOf('b');
 
 		// Assert
 		assertEquals(2, res);
 	}
 
 	@Test
 	public void indexOf_aabbccddd_b_3_ShouldReturn3() {
 		// Arrange
 		StringList sl = new StringList("aabbccddd");
 
 		// Act
 		int res = sl.indexOf('b', 3);
 
 		// Assert
 		assertEquals(3, res);
 	}
 
 	@Test
 	// Test ch doesn't exist from fromIndex
 	public void indexOf_aabbccddd_b_4_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList("aabbccddd");
 
 		// Act
 		int res = sl.indexOf('b', 4);
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	// Test fromIndex OutOfRange
 	public void indexOf_aa_a_4_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList("aa");
 
 		// Act
 		int res = sl.indexOf('a', 4);
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	// Test fromIndex OutOfRange
 	public void indexOf_aa_a_minus2_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList("aabbccddd");
 
 		// Act
 		int res = sl.indexOf('a', -2);
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	public void indexOf_EmptyStringList_a_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		int res = sl.indexOf('a');
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	public void indexOf_EmptyStringList_a_1_ShouldReturnMinus1() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		int res = sl.indexOf('a', 1);
 
 		// Assert
 		assertEquals(-1, res);
 	}
 
 	@Test
 	public void equals_EmptyStringList_null_ShouldReturnFalse() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		boolean res = sl.equals((StringList) null);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_EmptyStringList_EmptyStringList_ShouldReturnTrue() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		boolean res = sl.equals(new StringList());
 
 		// Assert
 		assertEquals(true, res);
 	}
 
 	@Test
 	public void equals_abc_null_ShouldReturnFalse() {
 		// Arrange
 		StringList sl = new StringList("abc");
 
 		// Act
 		boolean res = sl.equals((StringList) null);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_abc_EmptyStringList_ShouldReturnTrue() {
 		// Arrange
 		StringList sl = new StringList("abc");
 
 		// Act
 		boolean res = sl.equals(new StringList());
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_abc_abc_ShouldReturnTrue() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("abc");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(true, res);
 	}
 
 	@Test
 	public void equals_abc_def_ShouldReturnFalse() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("def");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_abc_ab_ShouldReturnFalse() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("ab");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_abc_abcc_ShouldReturnFalse() {
 		// Arrange
 		StringList sl1 = new StringList("abc");
 		StringList sl2 = new StringList("abcc");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_aabbccc_aabbccc_ShouldReturnTrue() {
 		// Arrange
 		StringList sl1 = new StringList("aabbccc");
 		StringList sl2 = new StringList("aabbccc");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(true, res);
 	}
 
 	@Test
 	public void equals_aabbccc_aabbddd_ShouldReturnTrue() {
 		// Arrange
 		StringList sl1 = new StringList("aabbccc");
 		StringList sl2 = new StringList("aabbddd");
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(false, res);
 	}
 
 	@Test
 	public void equals_abb_abb_Concat_ShouldReturnTrue() {
 		// Arrange
 		StringList sl1 = new StringList("abb");
 		StringList sl2 = new StringList("ab").concat(new StringList("b"));
 
 		// Act
 		boolean res = sl1.equals(sl2);
 
 		// Assert
 		assertEquals(true, res);
 	}
 
 	@Test
 	public void compareTo_EmptyString_EmptyString() {
 		compareToTest("", "");
 	}
 
 	@Test
 	public void compareTo_EmptyString_a_ShouldReturnNegative() {
 		compareToTest("", "a");
 	}
 
 	@Test
 	public void compareTo_a_a() {
 		compareToTest("a", "a");
 	}
 
 	@Test
 	public void compareTo_aa_aa() {
 		compareToTest("aa", "aa");
 	}
 
 	@Test
 	public void compareTo_a_aa() {
 		compareToTest("a", "aa");
 	}
 
 	@Test
 	public void compareTo_aac_aab() {
 		compareToTest("aac", "aab");
 	}
 
 	@Test
 	public void compareTo_aabb_aa() {
 		compareToTest("aabb", "aa");
 	}
 
 	@Test
 	public void compareTo_aabb_aab() {
 		compareToTest("aabb", "aab");
 	}
 
 	@Test
 	public void compareTo_aabbc_aabbbc() {
 		compareToTest("aabbc", "aabbbc");
 	}
 
 	@Test
 	public void compareTo_A_a() {
 		compareToTest("A", "a");
 	}
 
 	@Test
 	public void compareTo_a_B() {
 		compareToTest("a", "B");
 	}
 
 	@Test
 	public void compareTo_Aaa_aaa() {
 		compareToTest("Aaa", "aaa");
 	}
 
 	@Test
 	public void compareTo_StrangeChars_StrangeChars() {
 		compareToTest(")*(&$^%@#!", "!#@$%#^$&*()&");
 	}
 
 	@Test
 	public void compareTo_Itself() {
 		// Arrange
 		String s = "abc";
 		StringList sl = new StringList(s);
 
 		// Act
 		int exp1 = s.compareTo(s);
 		int res1 = sl.compareTo(sl);
 
 		// Assert
 		assertCompareTo(exp1, res1);
 	}
 
 	// The idea is to run the compareTo on "real" Java Strings and make sure our
 	// version of compareTo behaves the same.
 	private void compareToTest(String s1, String s2) {
 		// Arrange
 		StringList sl1 = new StringList(s1);
 		StringList sl2 = new StringList(s2);
 
 		// Act
 		int exp1 = s1.compareTo(s2);
 		int exp2 = s2.compareTo(s1);
 		int res1 = sl1.compareTo(sl2);
 		int res2 = sl2.compareTo(sl1);
 
 		// Assert
 		assertCompareTo(exp1, res1);
 		assertCompareTo(exp2, res2);
 	}
 
 	private void assertCompareTo(int expected, int actual) {
 		if (expected == 0) {
 			assertEquals(0, actual);
 		} else if (expected > 0) {
 			assertTrue(actual > 0);
 		} else // if (expected < 0)
 		{
 			assertTrue(actual < 0);
 		}
 	}
 
 	@Test
 	public void substring_EmptyString_0_ShouldReturnEmptyString() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		StringList res = sl.substring(0);
 
 		// Assert
 		assertEquals("", res.toString());
 	}
 
 	@Test
 	public void substring_a_0_ShouldReturn_a() {
 		// Arrange
 		StringList sl = new StringList("a");
 
 		// Act
 		StringList res = sl.substring(0);
 
 		// Assert
 		assertEquals("a", res.toString());
 	}
 
 	@Test
 	public void substring_aaa_0_ShouldReturn_aaa() {
 		// Arrange
 		StringList sl = new StringList("aaa");
 
 		// Act
 		StringList res = sl.substring(0);
 
 		// Assert
 		assertEquals("aaa", res.toString());
 	}
 
 	@Test
 	public void substring_aaa_1_ShouldReturn_aa() {
 		// Arrange
 		StringList sl = new StringList("aaa");
 
 		// Act
 		StringList res = sl.substring(1);
 
 		// Assert
 		assertEquals("aa", res.toString());
 	}
 
 	@Test
 	public void substring_aaabbc_1_ShouldReturn_aabbc() {
 		// Arrange
 		StringList sl = new StringList("aaabbc");
 
 		// Act
 		StringList res = sl.substring(1);
 
 		// Assert
 		assertEquals("aabbc", res.toString());
 	}
 
 	@Test
 	public void substring_aaabbc_4_ShouldReturn_bc() {
 		// Arrange
 		StringList sl = new StringList("aaabbc");
 
 		// Act
 		StringList res = sl.substring(4);
 
 		// Assert
 		assertEquals("bc", res.toString());
 	}
 
 	@Test
 	public void substring_abcdefg_2_5_ShouldReturn_cde() {
 		// Arrange
 		StringList sl = new StringList("abcdefg");
 
 		// Act
 		StringList res = sl.substring(2, 5);
 
 		// Assert
 		assertEquals("cde", res.toString());
 	}
 
 	@Test
 	// Check the case where i = j. According to Anita Cassapu it should return
 	// an empty StringList
 	public void substring_abcdefg_2_2_ShouldReturn_EmptyString() {
 		// Arrange
 		StringList sl = new StringList("abcdefg");
 
 		// Act
 		StringList res = sl.substring(2, 2);
 
 		// Assert
 		assertEquals("", res.toString());
 	}
 
 	@Test
 	public void substring_abbcdeeefg_1_6_ShouldReturn_bbcde() {
 		// Arrange
 		StringList sl = new StringList("abbcdeeefg");
 
 		// Act
 		StringList res = sl.substring(1, 6);
 
 		// Assert
 		assertEquals("bbcde", res.toString());
 	}
 
 	@Test
 	public void substring_aaaaaa_1_4_ShouldReturn_aaa() {
 		// Arrange
 		StringList sl = new StringList("aaaaaa");
 
 		// Act
 		StringList res = sl.substring(1, 4);
 
 		// Assert
 		assertEquals("aaa", res.toString());
 	}
 
 	@Test
 	public void substring_bbaaaaaa_2_4_ShouldReturn_aaa() {
 		// Arrange
 		StringList sl = new StringList("bbaaaaaa");
 
 		// Act
 		StringList res = sl.substring(2, 5);
 
 		// Assert
 		assertEquals("aaa", res.toString());
 	}
 
 	@Test
 	public void substring_aab_0_1_ShouldReturn_a() {
 		// Arrange
 		StringList sl = new StringList("aab");
 
 		// Act
 		StringList res = sl.substring(0, 1);
 
 		// Assert
 		assertEquals("a", res.toString());
 	}
 
 	@Test
 	public void substring_abbc_1_2_ShouldReturn_b() {
 		// Arrange
 		StringList sl = new StringList("abbc");
 
 		// Act
 		StringList res = sl.substring(1, 2);
 
 		// Assert
 		assertEquals("b", res.toString());
 	}
 
 	@Test
 	public void substring_abbc_2_3_ShouldReturn_b() {
 		// Arrange
 		StringList sl = new StringList("abbc");
 
 		// Act
 		StringList res = sl.substring(2, 3);
 
 		// Assert
 		assertEquals("b", res.toString());
 	}
 
 	@Test
 	public void substring_abb_2_3_ShouldReturn_b() {
 		// Arrange
 		StringList sl = new StringList("abb");
 
 		// Act
 		StringList res = sl.substring(2, 3);
 
 		// Assert
 		assertEquals("b", res.toString());
 	}
 
 	@Test
 	public void length_EmptyString_ShouldReturn0() {
 		// Arrange
 		StringList sl = new StringList();
 
 		// Act
 		int res = sl.length();
 
 		// Assert
 		assertEquals(0, res);
 	}
 
 	@Test
 	public void length_a_ShouldReturn1() {
 		// Arrange
 		StringList sl = new StringList("a");
 
 		// Act
 		int res = sl.length();
 
 		// Assert
 		assertEquals(1, res);
 	}
 
 	@Test
 	public void length_aaa_ShouldReturn3() {
 		// Arrange
 		StringList sl = new StringList("aaa");
 
 		// Act
 		int res = sl.length();
 
 		// Assert
 		assertEquals(3, res);
 	}
 
 	@Test
 	public void length_aaabbc_ShouldReturn6() {
 		// Arrange
 		StringList sl = new StringList("aaabbc");
 
 		// Act
 		int res = sl.length();
 
 		// Assert
 		assertEquals(6, res);
 	}
 }