Add simple tests

package.json

@@ -2,9 +2,9 @@
   "name": "@codewell/state-persistor",
   "version": "1.0.0",
   "description": "State persistor for front end applications",
-  "main": "src/index.js",
+  "main": "index.js",
   "scripts": {
-    "test": "jest",
+    "test": "npm run release && jest",
     "build": "rollup --config",
     "release": "npm run build:dev && npm run build:prod",
     "build:prod": "NODE_ENV=production rollup -c",

tests/index.test.js

@@ -0,0 +1,26 @@
+const devLib = require("../lib/dev");
+const prodLib = require("../lib/dev");
+
+test("That dev lib has saveState", () => {
+  expect(typeof devLib.saveState).toBe("function");
+});
+
+test("That dev lib has loadState", () => {
+  expect(typeof devLib.loadState).toBe("function");
+});
+
+test("That dev lib has purgeState", () => {
+  expect(typeof devLib.purgeState).toBe("function");
+});
+
+test("That prod lib has saveState", () => {
+  expect(typeof prodLib.saveState).toBe("function");
+});
+
+test("That prod lib has loadState", () => {
+  expect(typeof prodLib.loadState).toBe("function");
+});
+
+test("That prod lib has purgeState", () => {
+  expect(typeof prodLib.purgeState).toBe("function");
+});