Wrapping the example matrix with outer array (#1057)

Graphs/test/NumberOfIslands.test.js

@@ -0,0 +1,31 @@
+import { islands } from '../NumberOfIslands'
+
+describe('Number of Islands', () => {
+  test('Graph with three islands', () => {
+    const graph = [
+      ['1', '1', '0', '0', '0'],
+      ['1', '1', '0', '0', '0'],
+      ['0', '0', '1', '0', '0'],
+      ['0', '0', '0', '1', '1']
+    ]
+    expect(islands(graph)).toBe(3)
+  })
+
+  test('Graph with only one island', () => {
+    const graph = [
+      ['1', '1'],
+      ['1', '1'],
+      ['0', '0'],
+      ['0', '0']
+    ]
+    expect(islands(graph)).toBe(1)
+  })
+
+  test('No islands', () => {
+    const graph = [
+      ['0', '0'],
+      ['0', '0']
+    ]
+    expect(islands(graph)).toBe(0)
+  })
+})