Mark caesar as archived and move archived exercise to own folder (#336)

archive/archived_caesar/solution/caesar-solution.spec.js

@@ -0,0 +1,23 @@
+const caesar = require('./caesar-solution');
+
+test('works with single letters', () => {
+  expect(caesar('A', 1)).toBe('B');
+});
+test('works with words', () => {
+  expect(caesar('Aaa', 1)).toBe('Bbb');
+});
+test('works with phrases', () => {
+  expect(caesar('Hello, World!', 5)).toBe('Mjqqt, Btwqi!');
+});
+test('works with negative shift', () => {
+  expect(caesar('Mjqqt, Btwqi!', -5)).toBe('Hello, World!');
+});
+test('wraps', () => {
+  expect(caesar('Z', 1)).toBe('A');
+});
+test('works with large shift factors', () => {
+  expect(caesar('Hello, World!', 75)).toBe('Ebiil, Tloia!');
+});
+test('works with large negative shift factors', () => {
+  expect(caesar('Hello, World!', -29)).toBe('Ebiil, Tloia!');
+});