refactor: Enhance docs, add tests in PrintMatrixInSpiralOrder

Author: Hardvan

src/main/java/com/thealgorithms/others/PrintAMatrixInSpiralOrder.java

@@ -3,14 +3,39 @@
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Utility class to print a matrix in spiral order.
+ * <p>
+ * Given a 2D array (matrix), this class provides a method to return the
+ * elements
+ * of the matrix in spiral order, starting from the top-left corner and moving
+ * clockwise.
+ * </p>
+ *
+ * @author Sadiul Hakim (https://github.com/sadiul-hakim)
+ */
 public class PrintAMatrixInSpiralOrder {
+
     /**
-     * Search a key in row and column wise sorted matrix
+     * Returns the elements of the given matrix in spiral order.
+     *
+     * @param matrix the 2D array to traverse in spiral order
+     * @param row    the number of rows in the matrix
+     * @param col    the number of columns in the matrix
+     * @return a list containing the elements of the matrix in spiral order
+     *
+     *         <p>
+     *         Example:
      *
-     * @param matrix matrix to be searched
-     * @param row    number of rows matrix has
-     * @param col    number of columns matrix has
-     * @author Sadiul Hakim : https://github.com/sadiul-hakim
+     *         <pre>
+     * int[][] matrix = {
+     *   {1, 2, 3},
+     *   {4, 5, 6},
+     *   {7, 8, 9}
+     * };
+     * print(matrix, 3, 3) returns [1, 2, 3, 6, 9, 8, 7, 4, 5]
+     *         </pre>
+     *         </p>
      */
     public List<Integer> print(int[][] matrix, int row, int col) {
         // r traverses matrix row wise from first

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

@@ -0,0 +1,69 @@
+package com.thealgorithms.others;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class PrintAMatrixInSpiralOrderTest {
+
+    private final PrintAMatrixInSpiralOrder spiralPrinter = new PrintAMatrixInSpiralOrder();
+
+    @Test
+    void testSquareMatrix() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 6, 9, 8, 7, 4, 5);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 3));
+    }
+
+    @Test
+    void testRectangularMatrixMoreRows() {
+        int[][] matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 6, 9, 12, 11, 10, 7, 4, 5, 8);
+        assertEquals(expected, spiralPrinter.print(matrix, 4, 3));
+    }
+
+    @Test
+    void testRectangularMatrixMoreCols() {
+        int[][] matrix = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 4, 8, 12, 11, 10, 9, 5, 6, 7);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 4));
+    }
+
+    @Test
+    void testSingleRow() {
+        int[][] matrix = {{1, 2, 3, 4}};
+        List<Integer> expected = Arrays.asList(1, 2, 3, 4);
+        assertEquals(expected, spiralPrinter.print(matrix, 1, 4));
+    }
+
+    @Test
+    void testSingleColumn() {
+        int[][] matrix = {{1}, {2}, {3}};
+        List<Integer> expected = Arrays.asList(1, 2, 3);
+        assertEquals(expected, spiralPrinter.print(matrix, 3, 1));
+    }
+
+    @Test
+    void testEmptyMatrix() {
+        int[][] matrix = new int[0][0];
+        List<Integer> expected = Collections.emptyList();
+        assertEquals(expected, spiralPrinter.print(matrix, 0, 0));
+    }
+
+    @Test
+    void testOneElementMatrix() {
+        int[][] matrix = {{42}};
+        List<Integer> expected = Collections.singletonList(42);
+        assertEquals(expected, spiralPrinter.print(matrix, 1, 1));
+    }
+
+    @Test
+    void testMatrixWithNegativeNumbers() {
+        int[][] matrix = {{-1, -2}, {-3, -4}};
+        List<Integer> expected = Arrays.asList(-1, -2, -4, -3);
+        assertEquals(expected, spiralPrinter.print(matrix, 2, 2));
+    }
+}