merge: Add FibonacciNumber.js test case and update the decription of function. (#840)

Dynamic-Programming/tests/FibonacciNumber.test.js

@@ -0,0 +1,19 @@
+import { fibonacci } from '../FibonacciNumber'
+
+describe('FibonacciNumber', () => {
+  it('fibonacci of 0', () => {
+    expect(fibonacci(0)).toBe(0)
+  })
+
+  it('fibonacci of 1', () => {
+    expect(fibonacci(1)).toBe(1)
+  })
+
+  it('fibonacci of 10', () => {
+    expect(fibonacci(10)).toBe(55)
+  })
+
+  it('fibonacci of 25', () => {
+    expect(fibonacci(25)).toBe(75025)
+  })
+})