From b20fb7da17d79a51a845ff97755dd4a6978c0296 Mon Sep 17 00:00:00 2001
From: Stefan Martinov <stefan.martinov@gmail.com>
Date: Mon, 24 Aug 2020 14:35:19 +0200
Subject: [PATCH] feat: add update request queue test

---
 repo/loader_test.go | 65 +++++++++++++++++++++++++++++++++++++++++++++
 repo/repo.go        |  2 +-
 2 files changed, 66 insertions(+), 1 deletion(-)
 create mode 100644 repo/loader_test.go

diff --git a/repo/loader_test.go b/repo/loader_test.go
new file mode 100644
index 0000000..682034b
--- /dev/null
+++ b/repo/loader_test.go
@@ -0,0 +1,65 @@
+package repo
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var (
+	updateDuration = 5 * time.Millisecond
+)
+
+func TestRepo_tryUpdate(t *testing.T) {
+	repo := &Repo{
+		updateInProgressChannel: make(chan chan updateResponse, 1),
+	}
+
+	executed := make(chan time.Time, 4)
+
+	// Consumer For Updates
+	go func() {
+		for {
+			res := <-repo.updateInProgressChannel
+			now := time.Now()
+			executed <- now
+			time.Sleep(updateDuration)
+			res <- updateResponse{now.UnixNano(), nil}
+		}
+	}()
+
+	update := func(index int, expectError bool) {
+		go func() {
+			_, err := repo.tryUpdate()
+			assert.Equal(t, expectError, err != nil, "Error in request %d", index)
+		}()
+	}
+
+	// First one is being executed
+	update(0, false)
+	time.Sleep(1 * time.Millisecond)
+	assert.Equal(t, 1, len(executed))
+
+	// Second one is being queued
+	update(1, false)
+	time.Sleep(1 * time.Millisecond)
+	assert.Equal(t, 1, len(executed))
+
+	// Last one gets "Accepted"
+	time.Sleep(1 * time.Millisecond)
+	lastUpdateRequest := time.Now()
+	update(2, true)
+	assert.Equal(t, 1, len(executed))
+
+	<-executed // Dump first execution time
+
+	// Second execution should be done after given sleep time
+	time.Sleep(updateDuration)
+	assert.Equal(t, 1, len(executed))
+	lastUpdate := <-executed
+	assert.True(t, lastUpdate.After(lastUpdateRequest))
+
+	// When all requests are complete, allow queueing up again
+	update(3, false)
+}
diff --git a/repo/repo.go b/repo/repo.go
index 7bf302b..fec6c4d 100644
--- a/repo/repo.go
+++ b/repo/repo.go
@@ -62,7 +62,7 @@ func NewRepo(server string, varDir string) *Repo {
 		history:                    newHistory(varDir),
 		dimensionUpdateChannel:     make(chan *repoDimension),
 		dimensionUpdateDoneChannel: make(chan error),
-		updateInProgressChannel:    make(chan chan updateResponse, 0),
+		updateInProgressChannel:    make(chan chan updateResponse, 1),
 	}
 
 	go repo.updateRoutine()