From 10586bae95c1c825578fd26bb95fa3c159ea75ec Mon Sep 17 00:00:00 2001
From: pancho horrillo <pedrofelipe.horrillo@bbva.com>
Date: Mon, 7 Oct 2019 19:05:59 +0200
Subject: [PATCH] Add internal/server/user/server{,_test}.go
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Co-authored-by: Roberto Abdelkader Martínez Pérez <robertomartinezp@gmail.com>
---
 go.mod                              |   2 +-
 internal/server/user/server.go      |  31 +++++++
 internal/server/user/server_test.go | 123 ++++++++++++++++++++++++++++
 3 files changed, 155 insertions(+), 1 deletion(-)
 create mode 100644 internal/server/user/server.go
 create mode 100644 internal/server/user/server_test.go

diff --git a/go.mod b/go.mod
index 299196f..74eb86e 100644
--- a/go.mod
+++ b/go.mod
@@ -4,7 +4,7 @@ go 1.12
 
 require (
 	github.com/google/uuid v1.1.1 // indirect
-	github.com/gorilla/mux v1.7.3 // indirect
+	github.com/gorilla/mux v1.7.3
 	github.com/spf13/cobra v0.0.5
 	gopkg.in/h2non/gock.v1 v1.0.15
 )
diff --git a/internal/server/user/server.go b/internal/server/user/server.go
new file mode 100644
index 0000000..98edb84
--- /dev/null
+++ b/internal/server/user/server.go
@@ -0,0 +1,31 @@
+package user
+
+import (
+	"net/http"
+	"sync"
+
+	"github.com/gorilla/mux"
+)
+
+type swappableMux struct {
+	m    sync.RWMutex
+	root mux.Router
+}
+
+func (sm *swappableMux) get() mux.Router {
+	sm.m.RLock()
+	defer sm.m.RUnlock()
+
+	return sm.root
+}
+
+func (sm *swappableMux) set(mux mux.Router) {
+	sm.m.Lock()
+	sm.root = mux
+	sm.m.Unlock()
+}
+
+var Server http.Server
+
+func Run() {
+}
diff --git a/internal/server/user/server_test.go b/internal/server/user/server_test.go
new file mode 100644
index 0000000..c7d1777
--- /dev/null
+++ b/internal/server/user/server_test.go
@@ -0,0 +1,123 @@
+package user
+
+import (
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/gorilla/mux"
+)
+
+// TODO TestRunRunsAnHTTPServer(t *testing.T) {}
+
+func TestSwappableMuxGetReturnsTheCurrentMux(t *testing.T) {
+	sm := swappableMux{}
+	mux := sm.get()
+	if !reflect.DeepEqual(mux, sm.root) {
+		t.Errorf("Returned mux is not the same %#v", mux)
+	}
+}
+
+func TestSwappableMuxGetReturnsADifferentInstance(t *testing.T) {
+	sm := swappableMux{}
+	mux := sm.get()
+	if &mux == &sm.root {
+		t.Error("Returned mux is the same instance")
+	}
+}
+
+func TestSwappableMuxGetWaitsForTheMutexToBeReleased(t *testing.T) {
+	sm := swappableMux{}
+
+	sm.m.Lock()
+	defer sm.m.Unlock()
+
+	c := make(chan mux.Router)
+	go func() { c <- sm.get() }()
+
+	time.Sleep(10 * time.Millisecond)
+
+	select {
+	case <-c:
+		t.Error("Didn't acquire the mutex")
+	default:
+	}
+}
+
+func TestSwappableMuxGetIsAbleToReadWhileOthersAreReading(t *testing.T) {
+	sm := swappableMux{}
+
+	sm.m.RLock()
+	defer sm.m.RUnlock()
+
+	c := make(chan mux.Router)
+	go func() { c <- sm.get() }()
+
+	time.Sleep(10 * time.Millisecond)
+
+	select {
+	case <-c:
+	default:
+		t.Error("The mutex cannot be acquired")
+	}
+}
+
+func TestSwappableMuxSetSetsTheGivenMux(t *testing.T) {
+	sm := swappableMux{}
+	mux := mux.Router{
+		KeepContext: true,
+	}
+
+	sm.set(mux)
+
+	if !sm.root.KeepContext {
+		t.Error("mux not set")
+	}
+}
+
+func TestSwappableMuxSetSetsADifferentInstance(t *testing.T) {
+	sm := swappableMux{}
+	mux := mux.Router{}
+
+	sm.set(mux)
+
+	if &mux == &sm.root {
+		t.Error("Set mux is the same instance")
+	}
+}
+
+func TestSwappableMuxSetWaitsForWriterToReleaseMutex(t *testing.T) {
+	sm := swappableMux{}
+
+	sm.m.Lock()
+	defer sm.m.Unlock()
+
+	c := make(chan bool)
+	go func() { sm.set(mux.Router{}); c <- true }()
+
+	time.Sleep(10 * time.Millisecond)
+
+	select {
+	case <-c:
+		t.Error("Didn't acquire the mutex")
+	default:
+	}
+}
+
+func TestSwappableMuxSetWaitsForReadersToReleaseMutex(t *testing.T) {
+	sm := swappableMux{}
+
+	sm.m.RLock()
+	defer sm.m.RUnlock()
+
+	c := make(chan bool)
+	go func() { sm.set(mux.Router{}); c <- true }()
+
+	time.Sleep(10 * time.Millisecond)
+
+	select {
+	case <-c:
+		t.Error("Didn't acquire the mutex")
+	default:
+	}
+}