Mocha will not detect AssertionError exceptions inside a dependency mocked out using proxyquire when executing a middleware on an express app with supertest.

broken-test.js

var express    = require('express'),
    request    = require('supertest'),
    expect     = require('chai').expect,
    proxyquire = require('proxyquire');

var someplaceElsewhere = {
  configure: function () {
    return {
      callsThis: undefined,
      aMethod: function (query) {
        if (this.callsThis) {
          this.callsThis(query);
        }
      }
    };
  }
};

var middleware = proxyquire('./fake-middleware', { './someplace-elsewhere': someplaceElsewhere });

describe("Example", function () {
  var app;
  beforeEach(function () {
    middleware.configure();

    app = express();
    app.configure(function () {
      app.use(express.json());
      app.use(express.urlencoded()); // note: these two replace: app.use(express.bodyParser());
                                     // see:  http://stackoverflow.com/questions/19581146/how-to-get-rid-of-connect-3-0-deprecation-alert
      app.use(middleware.handle());
      app.use(app.router);
    });
    app.get('/test', function (req, res) {
      res.send('{ "success": true }');
    })
  });

  it("this should be a failure case but for some reason isn't", function (done) {
    middleware.middlewareClient.callsThis = function internalAssertions (query) {
      expect(query).to.equal("miaow");
    };
    request(app).get('/test?q=miao').end(done);
  });
});

fake-middleware.js

var someplaceElsewhereModule = require('./someplace-elsewhere');

var middleware = {
    configure: function () {
        this.middlewareClient = someplaceElsewhereModule.configure();
    },
    handle: function () {
        var middlewareScope = this;
        return function (req, res, next) {
            middlewareScope.middlewareClient.aMethod(req.query.q);
            next();
        };
    }
};

module.exports = middleware;

package.json

{
  "name"            : "not-capturing-assertion-error",
  "description"     : "Mocha won't catch my assertion error",
  "keywords"        : [
    "assertion",
    "error",
    "testing",
    "middleware",
    "mocha"
  ],
  "devDependencies" : {
    "express": "~3.4.7",
    "supertest": "0.8.2",
    "proxyquire": "0.5.2",
    "mocha": "*",
    "chai": "*"
  },
  "engines": {
    "node": "*"
  },
  "scripts": {
    "test": "mocha"
  }
}

someplace-elsewhere.js

var someplaceElsewhere = {
    configure: function () {
        return {
            aMethod: function (query) {

            }
        };
    }
};

module.exports = someplaceElsewhere;

See: http://stackoverflow.com/questions/20767336/unable-to-catch-exception-from-within-a-supertest-app-request