unit test and improve comments for new versioned costing for licenses

Author: williamstein

src/packages/util/licenses/purchase/compute-cost.test.ts

@@ -0,0 +1,103 @@
+import { compute_cost } from "./compute-cost";
+import { round2up } from "@cocalc/util/misc";
+
+describe("use the compute-cost function with v1 pricing, no version, and a test version to compute the price of a license", () => {
+  // This is a monthly business subscription for 3 projects with 1 cpu, 2 GB ram and 3 GB disk,
+  // using v1 pricing.  On the website right now it says this should cost:
+  //   "Cost: USD $27.15 monthly USD $9.05 per project"
+  const monthly1 = 27.15;
+  const info1 = {
+    version: "1",
+    end: new Date("2024-01-06T22:00:02.582Z"),
+    type: "quota",
+    user: "business",
+    boost: false,
+    start: new Date("2023-12-05T17:15:55.781Z"),
+    upgrade: "custom",
+    quantity: 3,
+    account_id: "6aae57c6-08f1-4bb5-848b-3ceb53e61ede",
+    custom_cpu: 1,
+    custom_ram: 2,
+    custom_disk: 3,
+    subscription: "monthly",
+    custom_member: true,
+    custom_uptime: "short",
+    custom_dedicated_cpu: 0,
+    custom_dedicated_ram: 0,
+  } as const;
+
+  it("computes the cost", () => {
+    const cost1 = compute_cost(info1);
+    expect(round2up(cost1.cost_sub_month * cost1.quantity)).toBe(monthly1);
+  });
+
+  it("computes correct cost when version not given (since version 1 is the default)", () => {
+    const info = { ...info1 };
+    // @ts-ignore
+    delete info["version"];
+    const cost = compute_cost(info);
+    expect(round2up(cost.cost_sub_month * cost.quantity)).toBe(monthly1);
+  });
+
+  it("computes correct cost with a different version of pricing params", () => {
+    const info = { ...info1 };
+    // @ts-ignore
+    info.version = "test_1";
+    const cost = compute_cost(info);
+    expect(round2up(cost.cost_sub_month * cost.quantity)).toBe(54.29);
+  });
+});
+
+describe("a couple more consistency checks with prod", () => {
+  // each price below comes from just configuring this on prod
+
+  it("computes the cost of a yearly academic license sub", () => {
+    const yearly = 306.98; // from prod store
+    const info = {
+      version: "1",
+      end: new Date("2024-01-06T22:00:02.582Z"),
+      type: "quota",
+      user: "academic",
+      boost: false,
+      start: new Date("2023-12-05T17:15:55.781Z"),
+      upgrade: "custom",
+      quantity: 3,
+      account_id: "6aae57c6-08f1-4bb5-848b-3ceb53e61ede",
+      custom_cpu: 2,
+      custom_ram: 2,
+      custom_disk: 3,
+      subscription: "yearly",
+      custom_member: true,
+      custom_uptime: "short",
+      custom_dedicated_cpu: 0,
+      custom_dedicated_ram: 0,
+    } as const;
+    const cost = compute_cost(info);
+    expect(round2up(cost.cost_sub_year * cost.quantity)).toBe(yearly);
+  });
+
+  it("computes the cost of a specific period academic license", () => {
+    const amount = 29.61; // from prod store
+    const info = {
+      version: "1",
+      start: new Date("2024-08-01T00:00:00.000Z"),
+      type: "quota",
+      user: "academic",
+      boost: false,
+      end: new Date("2024-08-31T00:00:00.000Z"),
+      upgrade: "custom",
+      quantity: 3,
+      account_id: "6aae57c6-08f1-4bb5-848b-3ceb53e61ede",
+      custom_cpu: 2,
+      custom_ram: 2,
+      custom_disk: 3,
+      subscription: "no",
+      custom_member: true,
+      custom_uptime: "short",
+      custom_dedicated_cpu: 0,
+      custom_dedicated_ram: 0,
+    } as const;
+    const cost = compute_cost(info);
+    expect(round2up(cost.cost)).toBe(amount);
+  });
+});

src/packages/util/licenses/purchase/compute-cost.ts

@@ -10,8 +10,23 @@ import {
 } from "@cocalc/util/consts/site-license";
 import { BASIC, getCosts, MAX, STANDARD } from "./consts";
 import { dedicatedPrice } from "./dedicated-price";
-import { Cost, PurchaseInfo } from "./types";
-
+import type { Cost, PurchaseInfo } from "./types";
+
+// NOTE: the PurchaseInfo object optionally has a "version" field in it.
+// If the version is not specified, then it defaults to "1", which is the version
+// when we started versioning prices.  If it is something else, then different
+// cost parameters may be used in the algorithm below -- that's what's currently
+// implemented.  However... maybe we want a new cost function entirely?  That's
+// possible too:
+//    - just call a new function for your new version below (that's the easy part), and
+//    - there is frontend and other UI code that depends on the structure exported
+//      by contst.ts, and anything that uses that MUST be updated accordingly.  E.g.,
+//      there are tables with example costs for various scenarios, stuff about academic
+//      discounts, etc., and a completely different cost function would need to explain
+//      all that differently to users.
+// OBVIOUSLY: NEVER EVER CHANGE the code or parameters that compute the value of
+// a specific version of a license!  If you make any change, then you must assign a
+// new version number and also keep the old version around.
 export function compute_cost(info: PurchaseInfo): Cost {
   if (info.type === "disk" || info.type === "vm") {
     return compute_cost_dedicated(info);

src/packages/util/licenses/purchase/cost-versions.ts

@@ -3,6 +3,10 @@
 // the value of any existing licenses.  For pay-as-you-go, on the other hand, the charges
 // are always short live and ephemeral, and the parameters for them are in the database.
 
+// OBVIOUSLY: NEVER EVER CHANGE the existing parameters that define the value of
+// a specific released version of a license!  If you make any change, then you must assign a
+// new version number and also keep the old version around!!!!
+
 const COST = {
   1: {
     // Subscription discount
@@ -45,6 +49,24 @@ const COST = {
     // easily be used about half of the time during a week in a large class.
     ALWAYS_RUNNING_FACTOR: 2,
   },
+
+  // this version is PURELY for testing purposes
+  test_1: {
+    SUB_DISCOUNT: { no: 1, monthly: 0.9, yearly: 0.85 },
+    GCE_COSTS: {
+      ram: 0.67,
+      cpu: 5,
+      disk: 0.04,
+      non_pre_factor: 3.5,
+    },
+    COST_MULTIPLIER: 1.6, // double version 1
+    NONMEMBER_DENSITY: 2,
+    ACADEMIC_DISCOUNT: 0.6,
+    DISK_FACTOR: 10,
+    RAM_OVERCOMMIT: 5,
+    CPU_OVERCOMMIT: 10,
+    ALWAYS_RUNNING_FACTOR: 2,
+  },
 } as const;
 
 export default COST;