DataDog and StatsD Metrics Support

* Added support for DataDog and StatsD monitoring
* Added documentation

vendor/github.com/stvp/go-udp-testing/udp.go

@@ -0,0 +1,192 @@
+// Package udp implements UDP test helpers. It lets you assert that certain
+// strings must or must not be sent to a given local UDP listener.
+package udp
+
+import (
+	"net"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+)
+
+var (
+	addr     *string
+	listener *net.UDPConn
+	Timeout  time.Duration = time.Millisecond
+)
+
+type fn func()
+
+// SetAddr sets the UDP port that will be listened on.
+func SetAddr(a string) {
+	addr = &a
+}
+
+func start(t *testing.T) {
+	resAddr, err := net.ResolveUDPAddr("udp", *addr)
+	if err != nil {
+		t.Fatal(err)
+	}
+	listener, err = net.ListenUDP("udp", resAddr)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func stop(t *testing.T) {
+	if err := listener.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func getMessage(t *testing.T, body fn) string {
+	start(t)
+	defer stop(t)
+
+	result := make(chan string)
+
+	go func() {
+		message := make([]byte, 1024*32)
+		var bufLen int
+		for {
+			listener.SetReadDeadline(time.Now().Add(Timeout))
+			n, _, _ := listener.ReadFrom(message[bufLen:])
+			if n == 0 {
+				result <- string(message[0:bufLen])
+				break
+			} else {
+				bufLen += n
+			}
+		}
+	}()
+
+	body()
+
+	return <-result
+}
+
+func get(t *testing.T, match string, body fn) (got string, equals bool, contains bool) {
+	got = getMessage(t, body)
+	equals = got == match
+	contains = strings.Contains(got, match)
+	return got, equals, contains
+}
+
+func printLocation(t *testing.T) {
+	_, file, line, _ := runtime.Caller(2)
+	t.Errorf("At: %s:%d", file, line)
+}
+
+// ShouldReceiveOnly will fire a test error if the given function doesn't send
+// exactly the given string over UDP.
+func ShouldReceiveOnly(t *testing.T, expected string, body fn) {
+	got, equals, _ := get(t, expected, body)
+	if !equals {
+		printLocation(t)
+		t.Errorf("Expected: %#v", expected)
+		t.Errorf("But got: %#v", got)
+	}
+}
+
+// ShouldNotReceiveOnly will fire a test error if the given function sends
+// exactly the given string over UDP.
+func ShouldNotReceiveOnly(t *testing.T, notExpected string, body fn) {
+	_, equals, _ := get(t, notExpected, body)
+	if equals {
+		printLocation(t)
+		t.Errorf("Expected not to get: %#v", notExpected)
+	}
+}
+
+// ShouldReceive will fire a test error if the given function doesn't send the
+// given string over UDP.
+func ShouldReceive(t *testing.T, expected string, body fn) {
+	got, _, contains := get(t, expected, body)
+	if !contains {
+		printLocation(t)
+		t.Errorf("Expected to find: %#v", expected)
+		t.Errorf("But got: %#v", got)
+	}
+}
+
+// ShouldNotReceive will fire a test error if the given function sends the
+// given string over UDP.
+func ShouldNotReceive(t *testing.T, expected string, body fn) {
+	got, _, contains := get(t, expected, body)
+	if contains {
+		printLocation(t)
+		t.Errorf("Expected not to find: %#v", expected)
+		t.Errorf("But got: %#v", got)
+	}
+}
+
+// ShouldReceiveAll will fire a test error unless all of the given strings are
+// sent over UDP.
+func ShouldReceiveAll(t *testing.T, expected []string, body fn) {
+	got := getMessage(t, body)
+	failed := false
+
+	for _, str := range expected {
+		if !strings.Contains(got, str) {
+			if !failed {
+				printLocation(t)
+				failed = true
+			}
+			t.Errorf("Expected to find: %#v", str)
+		}
+	}
+
+	if failed {
+		t.Errorf("But got: %#v", got)
+	}
+}
+
+// ShouldNotReceiveAny will fire a test error if any of the given strings are
+// sent over UDP.
+func ShouldNotReceiveAny(t *testing.T, unexpected []string, body fn) {
+	got := getMessage(t, body)
+	failed := false
+
+	for _, str := range unexpected {
+		if strings.Contains(got, str) {
+			if !failed {
+				printLocation(t)
+				failed = true
+			}
+			t.Errorf("Expected not to find: %#v", str)
+		}
+	}
+
+	if failed {
+		t.Errorf("But got: %#v", got)
+	}
+}
+
+func ShouldReceiveAllAndNotReceiveAny(t *testing.T, expected []string, unexpected []string, body fn) {
+	got := getMessage(t, body)
+	failed := false
+
+	for _, str := range expected {
+		if !strings.Contains(got, str) {
+			if !failed {
+				printLocation(t)
+				failed = true
+			}
+			t.Errorf("Expected to find: %#v", str)
+		}
+	}
+	for _, str := range unexpected {
+		if strings.Contains(got, str) {
+			if !failed {
+				printLocation(t)
+				failed = true
+			}
+			t.Errorf("Expected not to find: %#v", str)
+		}
+	}
+
+	if failed {
+		t.Errorf("but got: %#v", got)
+	}
+}