6.6.4. Двухмерный массив. Таблица умножения;

https://job4j.ru/profile/exercise/2/task-view/111

src/main/java/ru/j4j/array/Matrix.java

@@ -0,0 +1,13 @@
+package ru.j4j.array;
+
+public class Matrix {
+    public static int[][] multiple(int size) {
+        int[][] table = new int[size][size];
+        for (int row = 0; row < table.length; row++) {
+            for (int cell = 0; cell < table[row].length; cell++) {
+                table[row][cell] = (row + 1) * (cell + 1);
+            }
+        }
+        return table;
+    }
+}

src/test/java/ru/j4j/array/MatrixTest.java

@@ -0,0 +1,32 @@
+package ru.j4j.array;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class MatrixTest {
+    @Test
+    public void when2on2() {
+        int size = 2;
+        int[][] result = Matrix.multiple(size);
+        int[][] expected = {
+                {1, 2},
+                {2, 4}
+        };
+        assertThat(result).isDeepEqualTo(expected);
+    }
+
+    @Test
+    public void when5on5() {
+        int size = 5;
+        int[][] result = Matrix.multiple(size);
+        int[][] expected = {
+                {1, 2, 3, 4, 5},
+                {2, 4, 6, 8, 10},
+                {3, 6, 9, 12, 15},
+                {4, 8, 12, 16, 20},
+                {5, 10, 15, 20, 25}
+        };
+        assertThat(result).isDeepEqualTo(expected);
+    }
+}