feat: add support for dialects

src/MockClient.ts

@@ -10,6 +10,10 @@ export class MockClient extends knex.Client {
     super(config);
 
     MockClient.tracker = new Tracker(config.mockClient);
+
+    if (config.dialect) {
+      this._attachDialectQueryCompiler(config);
+    }
   }
 
   public acquireConnection() {
@@ -44,4 +48,20 @@ export class MockClient extends knex.Client {
 
     return MockClient.tracker._handle({ ...rawQuery, method });
   }
+
+  private _attachDialectQueryCompiler(config: Knex.Config<any> & { mockClient: TrackerConfig }) {
+    const { resolveClientNameWithAliases } = require('knex/lib/util/helpers');
+    const { SUPPORTED_CLIENTS } = require('knex/lib/constants');
+
+    if (!SUPPORTED_CLIENTS.includes(config.dialect)) {
+      throw new Error(
+        `knex-mock-client: Unknown configuration option 'dialect' value ${config.dialect}.\nNote that it is case-sensitive, check documentation for supported values.`
+      );
+    }
+
+    const resolvedClientName = resolveClientNameWithAliases(config.dialect);
+    const Dialect = require(`knex/lib/dialects/${resolvedClientName}/index.js`);
+    const dialect = new Dialect(config);
+    this.queryCompiler = dialect.queryCompiler.bind(this);
+  }
 }

tests/dialects.spec.ts

@@ -0,0 +1,53 @@
+import faker from 'faker';
+import knex, { Knex } from 'knex';
+import { getTracker, MockClient, Tracker } from '../src';
+
+describe('specific dialect', () => {
+  let db: Knex;
+  let tracker: Tracker;
+
+  describe('postgres', () => {
+    beforeAll(() => {
+      db = knex({
+        client: MockClient,
+        dialect: 'pg',
+      });
+      tracker = getTracker();
+    });
+
+    afterEach(() => {
+      tracker.reset();
+    });
+
+    it('should allow to mock select query distinctOn', async () => {
+      const givenData = [{ id: faker.datatype.number() }];
+      tracker.on.select('table_name').response(givenData);
+
+      const data = await db('table_name').distinctOn('age');
+
+      expect(data).toEqual(givenData);
+      expect(tracker.history.select).toHaveLength(1);
+    });
+
+    it('should allow to mock select query noWait', async () => {
+      const givenData = [{ id: faker.datatype.number() }];
+      tracker.on.select('table_name').response(givenData);
+
+      const data = await db('table_name').select('*').forUpdate().noWait();
+
+      expect(data).toEqual(givenData);
+      expect(tracker.history.select).toHaveLength(1);
+    });
+  });
+
+  describe('none-exists', () => {
+    it('should should throw an error when passing none exists dialect', () => {
+      expect(() =>
+        knex({
+          client: MockClient,
+          dialect: 'none-exists',
+        })
+      ).toThrowError(/Unknown configuration option 'dialect'/);
+    });
+  });
+});