Add tests for 2D array binary search (#3892)

src/test/java/com/thealgorithms/searches/BinarySearch2dArrayTest.java

@@ -1,9 +1,12 @@
 package com.thealgorithms.searches;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.*;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.AfterAll;
+
 
 public class BinarySearch2dArrayTest {
 
@@ -97,4 +100,67 @@ public class BinarySearch2dArrayTest {
         assertEquals(-1, ans[0]);
         assertEquals(-1, ans[1]);
     }
+
+    /**
+     * Test if the method works with input arrays consisting only of one row.
+     */
+    @Test
+    public void BinarySearch2dArrayTestOneRow() {
+        int[][] arr = { { 1, 2, 3, 4 }};
+        int target = 2;
+
+        // Assert that the requirement, that the array only has one row, is fulfilled.
+        assertEquals(arr.length, 1);
+        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        System.out.println(Arrays.toString(ans));
+        assertEquals(0, ans[0]);
+        assertEquals(1, ans[1]);
+    }
+
+    /**
+     * Test if the method works with the target in the middle of the input.
+     */
+    @Test
+    public void BinarySearch2dArrayTestTargetInMiddle() {
+        int[][] arr = { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 }, { 11, 12, 13, 14, 15} };
+        int target = 8;
+        // Assert that the requirement, that the target is in the middle row and middle column, is fulfilled.
+        assertEquals(arr[arr.length/2][arr[0].length/2], target);
+        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        System.out.println(Arrays.toString(ans));
+        assertEquals(1, ans[0]);
+        assertEquals(2, ans[1]);
+    }
+
+    /**
+     * Test if the method works with the target in the middle column,
+     * in the row above the middle row.
+     */
+    @Test
+    public void BinarySearch2dArrayTestTargetAboveMiddleRowInMiddleColumn() {
+        int[][] arr = { { 1, 2, 3, 4 }, { 5, 6, 7, 8 }, { 9, 10, 11, 12 } };
+        int target = 3;
+
+        // Assert that the requirement, that he target is in the middle column,
+        // in an array with an even number of columns, and on the row "above" the middle row.
+        assertEquals(arr[0].length % 2, 0);
+        assertEquals(arr[arr.length/2-1][arr[0].length/2], target);
+        int[] ans = BinarySearch2dArray.BinarySearch(arr, target);
+        System.out.println(Arrays.toString(ans));
+        assertEquals(0, ans[0]);
+        assertEquals(2, ans[1]);
+    }
+
+    /**
+     * Test if the method works with an empty array.
+     */
+    @Test
+    public void BinarySearch2dArrayTestEmptyArray() {
+        int[][] arr = {};
+        int target = 5;
+
+        // Assert that an empty array is not valid input for the method.
+        assertThrows(ArrayIndexOutOfBoundsException.class, () -> BinarySearch2dArray.BinarySearch(arr, target));
+    }
+
 }