got store working. now working on product-dimension switcher.

lib/__tests__/product-test.ts

@@ -0,0 +1,24 @@
+import { length } from "enheter";
+import { AreaProduct, LengthProduct, price } from "../product";
+
+describe("Product tests", () => {
+
+  it(`Length product gives correct price for a shorter length`, () => {
+    const standard = new LengthProduct(price("USD", 20), length("foot", 4));
+    const comparison = standard.priceFor(length("foot", 2));
+    expect(comparison.value).toEqual(10);
+  });
+
+  it(`Length product gives correct price for a longer length`, () => {
+    const standard = new LengthProduct(price("USD", 20), length("foot", 4));
+    const comparison = standard.priceFor(length("foot", 8));
+    expect(comparison.value).toEqual(40);
+  });
+
+  it(`Length product gives correct price if different units`, () => {
+    const standard = new LengthProduct(price("USD", 10), length("foot", 1));
+    const comparison = standard.priceFor(length("inch", 24));
+    expect(comparison.value).toEqual(20);
+  });
+
+});