// 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);
    }
}