Is there a way to force an aetest instance to run on a particular port?

Say I have some test functions like the following:

func TestMyFunction1(t *testing.T) {

    inst, err := aetest.NewInstance(&aetest.Options{StronglyConsistentDatastore: true})
    if err != nil {
        t.Fatalf("Failed to create instance: %v", err)
    }
    defer inst.Close()

    req1, err := inst.NewRequest("GET", "http://localhost:8080/api/some-resource", nil)
    if err != nil {
        t.Fatalf("Failed to create req1: %v", err)
    }
    c1 := appengine.NewContext(req1)

    resp1, err := appClient.Do(req1)

    if err != nil {
        t.Fatalf("Failed to create resp1: %v", err)
    }

    t.Log(resp1)

    // Run code and tests with *http.Request req1
    // and context.Context c1.
    // ...
}

When I run tests like these with goapp test, it appears that an aetest instance is created on a unique, random port when each test is invoked:

INFO     2018-01-29 20:56:27,504 api_server.py:205] Starting API server at: http://localhost:37243
INFO     2018-01-29 20:56:27,510 dispatcher.py:197] Starting module "default" running at: http://localhost:42184
INFO     2018-01-29 20:56:27,510 admin_server.py:116] Starting admin server at: http://localhost:43292


--- FAIL: TestMyFunction1 (2.00s)



INFO     2018-01-29 21:06:58,717 api_server.py:205] Starting API server at: http://localhost:43010
INFO     2018-01-29 21:06:58,718 dispatcher.py:197] Starting module "default" running at: http://localhost:37508
INFO     2018-01-29 21:06:58,719 admin_server.py:116] Starting admin server at: http://localhost:45493

--- FAIL: TestMyFunction2 (1.99s)

Is there a way to force an aetest instance to run on a particular port? Alternatively, is there a way to predetermine the port? It seems that goapp test wraps dev_appserver.py (which is where one would normally specify the port), and I can't specify a port when running goapp test. There is also no port property on the aetest Options struct.