diff --git a/command/agent/user_event.go b/command/agent/user_event.go
index 0540627acf..393193885a 100644
--- a/command/agent/user_event.go
+++ b/command/agent/user_event.go
@@ -230,7 +230,8 @@ func (a *Agent) UserEvents() []*UserEvent {
 func (a *Agent) LastUserEvent() *UserEvent {
 	a.eventLock.RLock()
 	defer a.eventLock.RUnlock()
-	idx := (a.eventIndex - 1) % len(a.eventBuf)
+	n := len(a.eventBuf)
+	idx := (((a.eventIndex - 1) % n) + n) % n
 	return a.eventBuf[idx]
 }
 
diff --git a/command/agent/user_event_test.go b/command/agent/user_event_test.go
new file mode 100644
index 0000000000..76a3e4bf62
--- /dev/null
+++ b/command/agent/user_event_test.go
@@ -0,0 +1,188 @@
+package agent
+
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/hashicorp/consul/consul/structs"
+	"github.com/hashicorp/consul/testutil"
+)
+
+func TestValidateUserEventParams(t *testing.T) {
+	p := &UserEvent{}
+	err := validateUserEventParams(p)
+	if err == nil || err.Error() != "User event missing name" {
+		t.Fatalf("err: %v", err)
+	}
+	p.Name = "foo"
+
+	p.NodeFilter = "("
+	err = validateUserEventParams(p)
+	if err == nil || !strings.Contains(err.Error(), "Invalid node filter") {
+		t.Fatalf("err: %v", err)
+	}
+
+	p.NodeFilter = ""
+	p.ServiceFilter = "("
+	err = validateUserEventParams(p)
+	if err == nil || !strings.Contains(err.Error(), "Invalid service filter") {
+		t.Fatalf("err: %v", err)
+	}
+
+	p.ServiceFilter = "foo"
+	p.TagFilter = "("
+	err = validateUserEventParams(p)
+	if err == nil || !strings.Contains(err.Error(), "Invalid tag filter") {
+		t.Fatalf("err: %v", err)
+	}
+
+	p.ServiceFilter = ""
+	p.TagFilter = "foo"
+	err = validateUserEventParams(p)
+	if err == nil || !strings.Contains(err.Error(), "tag filter without service") {
+		t.Fatalf("err: %v", err)
+	}
+}
+
+func TestShouldProcessUserEvent(t *testing.T) {
+	conf := nextConfig()
+	dir, agent := makeAgent(t, conf)
+	defer os.RemoveAll(dir)
+	defer agent.Shutdown()
+
+	srv1 := &structs.NodeService{
+		ID:      "mysql",
+		Service: "mysql",
+		Tags:    []string{"test", "foo", "bar", "master"},
+		Port:    5000,
+	}
+	agent.state.AddService(srv1)
+
+	p := &UserEvent{}
+	if !agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Bad node name
+	p = &UserEvent{
+		NodeFilter: "foobar",
+	}
+	if agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Good node name
+	p = &UserEvent{
+		NodeFilter: "^Node",
+	}
+	if !agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Bad service name
+	p = &UserEvent{
+		ServiceFilter: "foobar",
+	}
+	if agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Good service name
+	p = &UserEvent{
+		ServiceFilter: ".*sql",
+	}
+	if !agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Bad tag name
+	p = &UserEvent{
+		ServiceFilter: ".*sql",
+		TagFilter:     "slave",
+	}
+	if agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+
+	// Good service name
+	p = &UserEvent{
+		ServiceFilter: ".*sql",
+		TagFilter:     "master",
+	}
+	if !agent.shouldProcessUserEvent(p) {
+		t.Fatalf("bad")
+	}
+}
+
+func TestIngestUserEvent(t *testing.T) {
+	conf := nextConfig()
+	dir, agent := makeAgent(t, conf)
+	defer os.RemoveAll(dir)
+	defer agent.Shutdown()
+
+	for i := 0; i < 512; i++ {
+		msg := &UserEvent{LTime: uint64(i)}
+		agent.ingestUserEvent(msg)
+		if agent.LastUserEvent() != msg {
+			t.Fatalf("bad: %#v", msg)
+		}
+		events := agent.UserEvents()
+
+		expectLen := 256
+		if i < 256 {
+			expectLen = i + 1
+		}
+		if len(events) != expectLen {
+			t.Fatalf("bad: %d %d %d", i, expectLen, len(events))
+		}
+
+		counter := i
+		for j := len(events) - 1; j >= 0; j-- {
+			if events[j].LTime != uint64(counter) {
+				t.Fatalf("bad: %#v", events)
+			}
+			counter--
+		}
+	}
+}
+
+func TestFireReceiveEvent(t *testing.T) {
+	conf := nextConfig()
+	dir, agent := makeAgent(t, conf)
+	defer os.RemoveAll(dir)
+	defer agent.Shutdown()
+
+	srv1 := &structs.NodeService{
+		ID:      "mysql",
+		Service: "mysql",
+		Tags:    []string{"test", "foo", "bar", "master"},
+		Port:    5000,
+	}
+	agent.state.AddService(srv1)
+
+	p1 := &UserEvent{Name: "deploy", ServiceFilter: "web"}
+	err := agent.UserEvent(p1)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	p2 := &UserEvent{Name: "deploy"}
+	err = agent.UserEvent(p2)
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	testutil.WaitForResult(
+		func() (bool, error) {
+			return len(agent.UserEvents()) == 1, nil
+		},
+		func(err error) {
+			t.Fatalf("bad len")
+		})
+
+	last := agent.LastUserEvent()
+	if last.ID != p2.ID {
+		t.Fatalf("bad: %#v", last)
+	}
+}