feature: plugin API, working on #86

test/unit/index.js

@@ -12,6 +12,24 @@ describe('Liquid', function () {
       }).to.throw(/illegal root/)
     })
   })
+  describe('#plugin()', function () {
+    it('should call plugin on the instance', async function () {
+      const engine = new Liquid()
+      engine.plugin(function (Liquid) {
+        this.registerFilter('foo', x => `foo${x}foo`)
+      })
+      const html = await engine.parseAndRender('{{"bar"|foo}}')
+      expect(html).to.equal('foobarfoo')
+    })
+    it('should call plugin with Liquid', async function () {
+      const engine = new Liquid()
+      engine.plugin(function (Liquid) {
+        this.registerFilter('t', x => Liquid.isFalsy(x))
+      })
+      const html = await engine.parseAndRender('{{false|t}}')
+      expect(html).to.equal('true')
+    })
+  })
   describe('#express()', function () {
     const liquid = new Liquid({root: '/root'})
     const render = liquid.express()