Clean up proxyquired module after restoring cache

If a module is loaded for the first time via proxyquire, it should be deleted from cache after loading. Previously we were only capturing an existing cached module and restoring it after loading.

lib/proxyquire.js

@@ -279,6 +279,8 @@ Proxyquire.prototype._disableModuleCache = function (path, module) {
   return function () {
     if (cached) {
       Module._cache[id] = cached
+    } else {
+      delete Module._cache[id]
     }
   }
 }

test/proxyquire-cache.js

@@ -17,6 +17,15 @@ describe('Proxyquire', function () {
       assert.equal('cached', foo.state)
       assert.equal(foo, original)
     })
+
+    it('does not pollute the cache when module is proxyquired before it is loaded', function () {
+      var proxyquire = require('..')
+
+      proxyquire('./samples/no-call-thru-test', { './required': false })
+      var original = require('./samples/no-call-thru-test')
+
+      assert.equal(original.original, true)
+    })
   })
 
   describe('preserveCache()', function () {

test/samples/no-call-thru-test/index.js

@@ -0,0 +1 @@
+exports.original = require('./required')

test/samples/no-call-thru-test/required.js

@@ -0,0 +1 @@
+module.exports = true