Added Rates Service: Base, Coinbase, Composite

2025-04-28 12:36:30 +00:00
parent c168d6124e
commit a0395514ba
8 changed files with 590 additions and 6 deletions
@@ -0,0 +1,136 @@
+// Tests for CoinbaseRates: verifies public endpoints and conversion logic using stubs
+import { describe, it, expect, vi } from 'vitest';
+import { Satoshis } from '@xocash/primitives';
+
+import {
+  RatesCoinbase,
+  type CoinbaseProduct,
+} from '~/src/index.js';
+
+// CoinbaseRates implements BaseRates via Coinbase Exchange REST API
+describe('CoinbaseRates', () => {
+  it('listProducts should fetch and return product list', async () => {
+    // Arrange: prepare a fake product list and stub fetcher to return it
+    const sampleProducts: CoinbaseProduct[] = [
+      {
+        id: 'BCH-USD',
+        base_currency: 'BCH',
+        quote_currency: 'USD',
+        base_min_size: '0.00000001',
+        base_max_size: '1000000',
+        quote_increment: '0.01',
+      }
+    ];
+    const fetcher = vi.fn().mockResolvedValue({
+      ok: true,
+      json: async () => sampleProducts
+    } as any);
+
+    // Act: instantiate and call listProducts()
+    const rates = RatesCoinbase.from('https://api.exchange.coinbase.com', 1000, fetcher);
+    const products = await rates.listProducts();
+
+    // Assert: fetcher was invoked on the correct endpoint and data matches
+    expect(fetcher).toHaveBeenCalledWith('https://api.exchange.coinbase.com/products');
+    expect(products).toEqual(sampleProducts);
+  });
+
+  it('getRate should fetch direct pair and cache result', async () => {
+    // Arrange: stub ticker endpoint to return price '2' for direct pair
+    const tickerResponse = { ok: true, json: async () => ({ price: '2' }) } as any;
+    const fetcher = vi.fn().mockResolvedValue(tickerResponse);
+    const rates = RatesCoinbase.from('https://api.exchange.coinbase.com', 1000, fetcher);
+
+    // Act: first call should invoke fetcher for the direct BCH-USD ticker
+    const rate1 = await rates.getRate('USD');
+    // Assert: parsed value is correct and fetcher was called against the correct URL
+    expect(rate1).toBe(0.5);
+    expect(fetcher).toHaveBeenCalledWith(
+      'https://api.exchange.coinbase.com/products/USD-BCH/ticker',
+    );
+
+    // Act: second call should hit the cache (no new network call)
+    const rate2 = await rates.getRate('USD');
+    // Assert: value unchanged and fetcher not called again
+    expect(rate2).toBe(0.5);
+    expect(fetcher).toHaveBeenCalledTimes(1);
+  });
+
+  it('getRate should fallback to inverse when direct fails', async () => {
+    // Arrange: make the direct FETCH fail, then succeed for inverse fetch
+    const error = new Error('not found');
+    const inverseResponse = { ok: true, json: async () => ({ price: '4' }) } as any;
+    const fetcher = vi.fn()
+      .mockRejectedValueOnce(error)         // direct USD-BCH will throw
+      .mockResolvedValueOnce(inverseResponse); // then BCH-USD returns price
+    const rates = RatesCoinbase.from('https://api.exchange.coinbase.com', 1000, fetcher);
+
+    // Act: calling getRate on currencies that require inversion
+    const rate = await rates.getRate('USD');
+
+    // Assert: fetcher first called with USD-BCH then BCH-USD, and final rate is inverted correctly
+    expect(fetcher).toHaveBeenNthCalledWith(
+      1,
+      'https://api.exchange.coinbase.com/products/USD-BCH/ticker'
+    );
+    expect(fetcher).toHaveBeenNthCalledWith(
+      2,
+      'https://api.exchange.coinbase.com/products/BCH-USD/ticker'
+    );
+    expect(rate).toBe(4);
+  });
+
+  it('toBCH and fromBCH should convert amounts using getRate', async () => {
+    // Arrange: create rates instance and stub getRate to return a deterministic factor
+    const tickerResponse = { ok: true, json: async () => ({ price: '2' }) } as any;
+    const fetcher = vi.fn().mockResolvedValue(tickerResponse);
+    const rates = RatesCoinbase.from('https://api.exchange.coinbase.com', 1000, fetcher);
+    // Value returned is 1 usd = 0.5 bch
+    vi.spyOn(rates, 'getRate').mockResolvedValue(2 as any);
+
+    // Act: convert 2 units of foreign currency to BCH
+    const satoshis = await rates.toBCH(2, 'USD');
+    // Assert: 2 / rate (2) => 1 BCH
+    expect(satoshis.toBCH()).toBe(1);
+
+    // Act: convert 2 BCH back to foreign currency
+    const foreignAmount = await rates.fromBCH(Satoshis.fromBCH(2), 'USD');
+    // Assert: 2 BCH * rate (2) => 4 units of foreign currency
+    expect(foreignAmount).toBe(4);
+  });
+
+  // --- Integration tests against actual Coinbase API (no mocking) ---
+  it('integration: listProducts should return a non-empty array', async () => {
+    // Use default fetcher to call real /products endpoint
+    const rates = RatesCoinbase.from();
+    const products = await rates.listProducts();
+
+    // Expect an array of products and at least one result
+    expect(Array.isArray(products)).toBe(true);
+    expect(products.length).toBeGreaterThan(0);
+  });
+
+  it('integration: getRate BCH->USD should yield a positive number', async () => {
+    // Call real ticker endpoint
+    const rates = RatesCoinbase.from();
+    const rate = await rates.getRate('USD');
+
+    // Expect a numeric rate greater than zero
+    expect(typeof rate).toBe('number');
+    expect(rate).toBeGreaterThan(0);
+  });
+
+  it('integration: toBCH/fromBCH roundtrip with USD should work', async () => {
+    // Convert 1 USD to BCH (satoshis) then back to USD
+    const rates = RatesCoinbase.from();
+    const sats = await rates.toBCH(1, 'USD');
+    expect(sats.toBigInt()).toBeGreaterThan(BigInt(0));
+
+    const back = await rates.fromBCH(sats, 'USD');
+
+    expect(back).toBeGreaterThan(0);
+    expect(back).toBeCloseTo(1.00, 3);
+
+
+  }, { timeout: 20000 });
+});