Introduce framework for running basic tests for entities (#1344)

* Introduce framework for running basic tests for entities

* Add pipeline tests to CircleCI config

* Make pipeline tests more configurable and fix CircleCI config

* Add coverage dir to pipeline package

* Add basic tests for all exchange event entities

* Add tests for remaining entities

* Create separate test scripts in package.json and add new info to README

* Update db_setup.ts to revert migrations even if you are using docker

* Automatically pull the postgres image if needed

* Add comment about why NumberToBigIntTransformer is needed

packages/pipeline/test/entities/block_test.ts

@@ -0,0 +1,23 @@
+import 'mocha';
+import 'reflect-metadata';
+
+import { Block } from '../../src/entities';
+import { createDbConnectionOnceAsync } from '../db_setup';
+import { chaiSetup } from '../utils/chai_setup';
+
+import { testSaveAndFindEntityAsync } from './util';
+
+chaiSetup.configure();
+
+// tslint:disable:custom-no-magic-numbers
+describe('Block entity', () => {
+    it('save/find', async () => {
+        const connection = await createDbConnectionOnceAsync();
+        const block = new Block();
+        block.hash = '0x12345';
+        block.number = 1234567;
+        block.timestamp = 5432154321;
+        const blocksRepository = connection.getRepository(Block);
+        await testSaveAndFindEntityAsync(blocksRepository, block);
+    });
+});