Add tests for CountChar (#3334)

src/test/java/com/thealgorithms/others/CountCharTest.java

@@ -0,0 +1,17 @@
+package com.thealgorithms.others;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class CountCharTest {
+
+    @Test
+    void testCountCharacters(){
+        String input = "12345";
+        int expectedValue = 5;
+
+        assertEquals(expectedValue, CountChar.CountCharacters(input));
+    }
+
+}