fix(server): add unit test for plugin.js

lib/plugin.js

@@ -50,10 +50,9 @@ function resolve (plugins, emitter) {
   return modules
 }
 
-const pluginInstances = new Map()
-
 function createInstantiatePlugin (injector) {
   const emitter = injector.get('emitter')
+  const pluginInstances = new Map()
   return function instantiatePlugin (kind, name) {
     if (pluginInstances.has(name)) {
       return pluginInstances.get(name)
@@ -64,18 +63,17 @@ function createInstantiatePlugin (injector) {
       p = injector.get(`${kind}:${name}`)
       if (!p) {
         log.error(`Failed to instantiate ${kind} ${name}`)
-        emitter.emit('load_error', `${kind}`, name)
+        emitter.emit('load_error', kind, name)
       }
     } catch (e) {
       if (e.message.includes(`No provider for "${kind}:${name}"`)) {
-        log.error(`Can not load "${name}", it is not registered!\n  Perhaps you are missing some plugin?`)
+        log.error(`Cannot load "${name}", it is not registered!\n  Perhaps you are missing some plugin?`)
       } else {
-        log.error(`Can not load "${name}"!\n  ` + e.stack)
+        log.error(`Cannot load "${name}"!\n  ` + e.stack)
       }
-      emitter.emit('load_error', `${kind}`, name)
+      emitter.emit('load_error', kind, name)
     }
-
-    pluginInstances.set(name, p)
+    pluginInstances.set(name, p, `${kind}:${name}`)
     return p
   }
 }

test/unit/plugin.spec.js

@@ -0,0 +1,61 @@
+'use strict'
+
+const createInstantiatePlugin = require('../../lib/plugin').createInstantiatePlugin
+
+describe('plugin', () => {
+  describe('createInstantiatePlugin', () => {
+    it('creates the instantiatePlugin function', () => {
+      const fakeGet = sinon.stub()
+      const fakeInjector = { get: fakeGet }
+
+      expect(typeof createInstantiatePlugin(fakeInjector)).to.be.equal('function')
+      expect(fakeGet).to.have.been.calledWith('emitter')
+    })
+
+    it('creates the instantiatePlugin function', () => {
+      const fakes = {
+        emitter: { emit: sinon.stub() }
+      }
+      const fakeInjector = { get: (id) => fakes[id] }
+
+      const instantiatePlugin = createInstantiatePlugin(fakeInjector)
+      expect(typeof instantiatePlugin('kind', 'name')).to.be.equal('undefined')
+      expect(fakes.emitter.emit).to.have.been.calledWith('load_error', 'kind', 'name')
+    })
+
+    it('caches plugins', () => {
+      const fakes = {
+        emitter: { emit: sinon.stub() },
+        'kind:name': { my: 'plugin' }
+      }
+      const fakeInjector = {
+        get: (id) => {
+          return fakes[id]
+        }
+      }
+
+      const instantiatePlugin = createInstantiatePlugin(fakeInjector)
+      expect(instantiatePlugin('kind', 'name')).to.be.equal(fakes['kind:name'])
+      fakeInjector.get = (id) => { throw new Error('failed to cache') }
+      expect(instantiatePlugin('kind', 'name')).to.be.equal(fakes['kind:name'])
+    })
+
+    it('errors if the injector errors', () => {
+      const fakes = {
+        emitter: { emit: sinon.stub() }
+      }
+      const fakeInjector = {
+        get: (id) => {
+          if (id in fakes) {
+            return fakes[id]
+          }
+          throw new Error('fail')
+        }
+      }
+
+      const instantiatePlugin = createInstantiatePlugin(fakeInjector)
+      expect(typeof instantiatePlugin('unknown', 'name')).to.be.equal('undefined')
+      expect(fakes.emitter.emit).to.have.been.calledWith('load_error', 'unknown', 'name')
+    })
+  })
+})