add script test for StringCompression and StrStr

src/main/java/com/ctci/arraysandstrings/StringCompression.java

@@ -13,7 +13,7 @@ public class StringCompression {
      * @param str input string containing only a-z characters, both cases
      * @return which ever is the shorter string
      */
-    private static String compressString(String str) {
+     static String compressString(String str) {
         StringBuilder compressedSb = new StringBuilder();
         int countConsecutive = 0;
         for (int i = 0; i < str.length(); i++) {

src/main/java/com/ctci/arraysandstrings/StringCompressionTest.java

@@ -0,0 +1,43 @@
+package com.ctci.arraysandstrings;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StringCompressionTest {
+    @Test
+    public void stringCompression_EmptyString() {
+        String str = "";
+        assertEquals(StringCompression.compressString(""), "");
+    }
+
+    @Test
+    public void stringCompression_SingleCharacter() {
+        String str = "a";
+        assertEquals(StringCompression.compressString("a"), "a");
+    }
+
+    @Test
+    public void stringCompression_NoConsecutiveCharacter() {
+        String str = "abcdef";
+        assertEquals(StringCompression.compressString("abcdef"), "abcdef");
+    }
+
+    @Test
+    public void stringCompression_CompressedNotShorterThanOriginal() {
+        String str = "aabbccddee";
+        assertEquals(StringCompression.compressString("aabbccddee"), "aabbccddee");
+    }
+
+    @Test
+    public void stringCompression_LowercaseNexttoUppercase() {
+        String str = "aAbbBBBCCCCcccc";
+        assertEquals(StringCompression.compressString("aAbbBBBCCCCcccc"), "a1A1b2B3C4c4");
+    }
+
+    @Test
+    public void stringCompression_RandomString() {
+        String str = "aabcccccccccccccccccccccccccaaa";
+        assertEquals(StringCompression.compressString("aabcccccccccccccccccccccccccaaa"), "a2b1c25a3");
+    }
+}

src/main/java/com/leetcode/strings/StrStrTest.java

@@ -0,0 +1,56 @@
+package com.leetcode.strings;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StrStrTest {
+    @Test
+    public void strStr_EdgeCase1() {
+        String haystack = "";
+        String needle = "";
+        assertEquals(StrStr.strStr(haystack, needle), 0);
+    }
+
+    @Test
+    public void strStr_EdgeCase2() {
+        String haystack = "";
+        String needle = "abc";
+        assertEquals(StrStr.strStr(haystack, needle), -1);
+    }
+
+    @Test
+    public void strStr_EdgeCase3() {
+        String haystack = "aaaa";
+        String needle = "";
+        assertEquals(StrStr.strStr(haystack, needle), 0);
+    }
+
+    @Test
+    public void strStr_EdgeCase4() {
+        String haystack = "aaa";
+        String needle = "aaaa";
+        assertEquals(StrStr.strStr(haystack, needle), -1);
+    }
+
+    @Test
+    public void strStr_RandomCase1_NotFound() {
+        String haystack = "aaaa";
+        String needle = "bba";
+        assertEquals(StrStr.strStr(haystack, needle), -1);
+    }
+
+    @Test
+    public void strStr_RandomCase2_Found() {
+        String haystack = "mississippi";
+        String needle = "issip";
+        assertEquals(StrStr.strStr(haystack, needle), 4);
+    }
+
+    @Test
+    public void strStr_RandomCase3_Found() {
+        String haystack = "duuuuuuy";
+        String needle = "u";
+        assertEquals(StrStr.strStr(haystack, needle), 1);
+    }
+}