test(plugins): add missing tests for plugin resolution logic (#3661)

test/unit/plugin.spec.js

@@ -1,5 +1,7 @@
 'use strict'
 
+const path = require('path')
+const proxyquire = require('proxyquire')
 const createInstantiatePlugin = require('../../lib/plugin').createInstantiatePlugin
 
 describe('plugin', () => {
@@ -58,4 +60,51 @@ describe('plugin', () => {
       expect(fakes.emitter.emit).to.have.been.calledWith('load_error', 'unknown', 'name')
     })
   })
+
+  describe('resolve', () => {
+    // Base path should be the same as the one produced by the code under test.
+    const base = path.resolve(__dirname, '..', '..', '..')
+    const directories = {
+      [base]: ['karma-fancy-plugin', 'other-package', 'karma-powerful-plugin', 'yet-another-package', '@scope'],
+      [path.join(base, '@scope')]: ['karma-super-plugin', 'not-a-plugin']
+    }
+
+    const { resolve } = proxyquire(
+      '../../lib/plugin',
+      {
+        'graceful-fs': { readdirSync: (dir) => directories[dir] },
+        'karma-fancy-plugin': { name: 'karma-fancy-plugin', '@noCallThru': true },
+        'karma-powerful-plugin': { name: 'karma-powerful-plugin', '@noCallThru': true },
+        '@scope/karma-super-plugin': { name: '@scope/karma-super-plugin', '@noCallThru': true },
+        // Plugins are require()'d using an absolute path if they were resolved from the glob.
+        [path.join(base, 'karma-fancy-plugin')]: { name: 'karma-fancy-plugin', '@noCallThru': true },
+        [path.join(base, 'karma-powerful-plugin')]: { name: 'karma-powerful-plugin', '@noCallThru': true },
+        [path.join(base, '@scope/karma-super-plugin')]: { name: '@scope/karma-super-plugin', '@noCallThru': true }
+      }
+    )
+
+    it('loads simple plugin', () => {
+      const modules = resolve(['karma-powerful-plugin'], null)
+
+      expect(modules.map((m) => m.name)).to.deep.equal(['karma-powerful-plugin'])
+    })
+
+    it('loads scoped plugin', () => {
+      const modules = resolve(['@scope/karma-super-plugin'], null)
+
+      expect(modules.map((m) => m.name)).to.deep.equal(['@scope/karma-super-plugin'])
+    })
+
+    it('loads simple plugins with globs', () => {
+      const modules = resolve(['karma-*'], null)
+
+      expect(modules.map((m) => m.name)).to.deep.equal(['karma-fancy-plugin', 'karma-powerful-plugin'])
+    })
+
+    it('loads scoped plugins with globs', () => {
+      const modules = resolve(['@*/karma-*'], null)
+
+      expect(modules.map((m) => m.name)).to.deep.equal(['@scope/karma-super-plugin'])
+    })
+  })
 })