Token_orderbook_snapshots for Ddex and Paradex(#1354)

* Implements the TokenOrderbookSnapshot Table

* Scripts, Data Sources and Entities to pull Ddex and Paradex API data.

packages/pipeline/test/entities/token_order_test.ts

@@ -0,0 +1,31 @@
+import { BigNumber } from '@0x/utils';
+import 'mocha';
+
+import { TokenOrderbookSnapshot } from '../../src/entities';
+import { createDbConnectionOnceAsync } from '../db_setup';
+import { chaiSetup } from '../utils/chai_setup';
+
+import { testSaveAndFindEntityAsync } from './util';
+
+chaiSetup.configure();
+
+const tokenOrderbookSnapshot: TokenOrderbookSnapshot = {
+    source: 'ddextest',
+    observedTimestamp: Date.now(),
+    orderType: 'bid',
+    price: new BigNumber(10.1),
+    baseAssetSymbol: 'ETH',
+    baseAssetAddress: '0x818e6fecd516ecc3849daf6845e3ec868087b755',
+    baseVolume: new BigNumber(143),
+    quoteAssetSymbol: 'ABC',
+    quoteAssetAddress: '0x00923b9a074762b93650716333b3e1473a15048e',
+    quoteVolume: new BigNumber(12.3234234),
+};
+
+describe('TokenOrderbookSnapshot entity', () => {
+    it('save/find', async () => {
+        const connection = await createDbConnectionOnceAsync();
+        const tokenOrderbookSnapshotRepository = connection.getRepository(TokenOrderbookSnapshot);
+        await testSaveAndFindEntityAsync(tokenOrderbookSnapshotRepository, tokenOrderbookSnapshot);
+    });
+});