Add tests, remove main in TernarySearch (#5677)

Author: Hardvan

DIRECTORY.md

@@ -1022,6 +1022,7 @@
             * [SearchInARowAndColWiseSortedMatrixTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SearchInARowAndColWiseSortedMatrixTest.java)
             * [SortOrderAgnosticBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SortOrderAgnosticBinarySearchTest.java)
             * [SquareRootBinarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/SquareRootBinarySearchTest.java)
+            * [TernarySearchTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TernarySearchTest.java)
             * [TestSearchInARowAndColWiseSortedMatrix](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/TestSearchInARowAndColWiseSortedMatrix.java)
             * [UnionFindTest](https://github.com/TheAlgorithms/Java/blob/master/src/test/java/com/thealgorithms/searches/UnionFindTest.java)
           * sorts

src/main/java/com/thealgorithms/searches/TernarySearch.java

@@ -1,9 +1,6 @@
 package com.thealgorithms.searches;
 
 import com.thealgorithms.devutils.searches.SearchAlgorithm;
-import java.util.Arrays;
-import java.util.Random;
-import java.util.stream.Stream;
 
 /**
  * A ternary search algorithm is a technique in computer science for finding the
@@ -60,23 +57,4 @@ private <T extends Comparable<T>> int ternarySearch(T[] arr, T key, int start, i
             return ternarySearch(arr, key, mid1, mid2);
         }
     }
-
-    public static void main(String[] args) {
-        // just generate data
-        Random r = new Random();
-        int size = 100;
-        int maxElement = 100000;
-        Integer[] integers = Stream.generate(() -> r.nextInt(maxElement)).limit(size).sorted().toArray(Integer[] ::new);
-
-        // the element that should be found
-        Integer shouldBeFound = integers[r.nextInt(size - 1)];
-
-        TernarySearch search = new TernarySearch();
-        int atIndex = search.find(integers, shouldBeFound);
-
-        System.out.printf("Should be found: %d. Found %d at index %d. An array length %d%n", shouldBeFound, integers[atIndex], atIndex, size);
-
-        int toCheck = Arrays.binarySearch(integers, shouldBeFound);
-        System.out.printf("Found by system method at an index: %d. Is equal: %b%n", toCheck, toCheck == atIndex);
-    }
 }

src/test/java/com/thealgorithms/searches/TernarySearchTest.java

@@ -0,0 +1,81 @@
+package com.thealgorithms.searches;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class TernarySearchTest {
+
+    @Test
+    void testFindElementInSortedArray() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 5);
+
+        assertEquals(4, index, "Should find the element 5 at index 4");
+    }
+
+    @Test
+    void testElementNotFound() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 11);
+
+        assertEquals(-1, index, "Should return -1 for element 11 which is not present");
+    }
+
+    @Test
+    void testFindFirstElement() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 1);
+
+        assertEquals(0, index, "Should find the first element 1 at index 0");
+    }
+
+    @Test
+    void testFindLastElement() {
+        Integer[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 10);
+
+        assertEquals(9, index, "Should find the last element 10 at index 9");
+    }
+
+    @Test
+    void testFindInLargeArray() {
+        Integer[] arr = new Integer[1000];
+        for (int i = 0; i < 1000; i++) {
+            arr[i] = i + 1; // Array from 1 to 1000
+        }
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 500);
+
+        assertEquals(499, index, "Should find element 500 at index 499");
+    }
+
+    @Test
+    void testNegativeNumbers() {
+        Integer[] arr = {-10, -5, -3, -1, 0, 1, 3, 5, 7, 10};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, -3);
+
+        assertEquals(2, index, "Should find the element -3 at index 2");
+    }
+
+    @Test
+    void testEdgeCaseEmptyArray() {
+        Integer[] arr = {};
+        TernarySearch search = new TernarySearch();
+
+        int index = search.find(arr, 5);
+
+        assertEquals(-1, index, "Should return -1 for an empty array");
+    }
+}