Switch to ginkgo/gomega for tests

This switches over to ginkgo/gomega for tests, which makes writing
certain tests easier/more fluent in the future.

vendor/github.com/hpcloud/tail/ratelimiter/memory.go

@@ -0,0 +1,58 @@
+package ratelimiter
+
+import (
+	"errors"
+	"time"
+)
+
+const GC_SIZE int = 100
+
+type Memory struct {
+	store           map[string]LeakyBucket
+	lastGCCollected time.Time
+}
+
+func NewMemory() *Memory {
+	m := new(Memory)
+	m.store = make(map[string]LeakyBucket)
+	m.lastGCCollected = time.Now()
+	return m
+}
+
+func (m *Memory) GetBucketFor(key string) (*LeakyBucket, error) {
+
+	bucket, ok := m.store[key]
+	if !ok {
+		return nil, errors.New("miss")
+	}
+
+	return &bucket, nil
+}
+
+func (m *Memory) SetBucketFor(key string, bucket LeakyBucket) error {
+
+	if len(m.store) > GC_SIZE {
+		m.GarbageCollect()
+	}
+
+	m.store[key] = bucket
+
+	return nil
+}
+
+func (m *Memory) GarbageCollect() {
+	now := time.Now()
+
+	// rate limit GC to once per minute
+	if now.Add(60*time.Second).Unix() > m.lastGCCollected.Unix() {
+
+		for key, bucket := range m.store {
+			// if the bucket is drained, then GC
+			if bucket.DrainedAt().Unix() > now.Unix() {
+				delete(m.store, key)
+			}
+		}
+
+		m.lastGCCollected = now
+	}
+}