diff --git a/vendor/github.com/google/go-cmp/cmp/internal/value/format.go b/vendor/github.com/google/go-cmp/cmp/internal/value/format.go
new file mode 100644
index 0000000..657e508
--- /dev/null
+++ b/vendor/github.com/google/go-cmp/cmp/internal/value/format.go
@@ -0,0 +1,277 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package value provides functionality for reflect.Value types.
+package value
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+var stringerIface = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+
+// Format formats the value v as a string.
+//
+// This is similar to fmt.Sprintf("%+v", v) except this:
+//	* Prints the type unless it can be elided
+//	* Avoids printing struct fields that are zero
+//	* Prints a nil-slice as being nil, not empty
+//	* Prints map entries in deterministic order
+func Format(v reflect.Value, conf FormatConfig) string {
+	conf.printType = true
+	conf.followPointers = true
+	conf.realPointers = true
+	return formatAny(v, conf, nil)
+}
+
+type FormatConfig struct {
+	UseStringer        bool // Should the String method be used if available?
+	printType          bool // Should we print the type before the value?
+	PrintPrimitiveType bool // Should we print the type of primitives?
+	followPointers     bool // Should we recursively follow pointers?
+	realPointers       bool // Should we print the real address of pointers?
+}
+
+func formatAny(v reflect.Value, conf FormatConfig, visited map[uintptr]bool) string {
+	// TODO: Should this be a multi-line printout in certain situations?
+
+	if !v.IsValid() {
+		return "<non-existent>"
+	}
+	if conf.UseStringer && v.Type().Implements(stringerIface) && v.CanInterface() {
+		if (v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface) && v.IsNil() {
+			return "<nil>"
+		}
+
+		const stringerPrefix = "s" // Indicates that the String method was used
+		s := v.Interface().(fmt.Stringer).String()
+		return stringerPrefix + formatString(s)
+	}
+
+	switch v.Kind() {
+	case reflect.Bool:
+		return formatPrimitive(v.Type(), v.Bool(), conf)
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return formatPrimitive(v.Type(), v.Int(), conf)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		if v.Type().PkgPath() == "" || v.Kind() == reflect.Uintptr {
+			// Unnamed uints are usually bytes or words, so use hexadecimal.
+			return formatPrimitive(v.Type(), formatHex(v.Uint()), conf)
+		}
+		return formatPrimitive(v.Type(), v.Uint(), conf)
+	case reflect.Float32, reflect.Float64:
+		return formatPrimitive(v.Type(), v.Float(), conf)
+	case reflect.Complex64, reflect.Complex128:
+		return formatPrimitive(v.Type(), v.Complex(), conf)
+	case reflect.String:
+		return formatPrimitive(v.Type(), formatString(v.String()), conf)
+	case reflect.UnsafePointer, reflect.Chan, reflect.Func:
+		return formatPointer(v, conf)
+	case reflect.Ptr:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("(%v)(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		if visited[v.Pointer()] || !conf.followPointers {
+			return formatPointer(v, conf)
+		}
+		visited = insertPointer(visited, v.Pointer())
+		return "&" + formatAny(v.Elem(), conf, visited)
+	case reflect.Interface:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		return formatAny(v.Elem(), conf, visited)
+	case reflect.Slice:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		if visited[v.Pointer()] {
+			return formatPointer(v, conf)
+		}
+		visited = insertPointer(visited, v.Pointer())
+		fallthrough
+	case reflect.Array:
+		var ss []string
+		subConf := conf
+		subConf.printType = v.Type().Elem().Kind() == reflect.Interface
+		for i := 0; i < v.Len(); i++ {
+			s := formatAny(v.Index(i), subConf, visited)
+			ss = append(ss, s)
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	case reflect.Map:
+		if v.IsNil() {
+			if conf.printType {
+				return fmt.Sprintf("%v(nil)", v.Type())
+			}
+			return "<nil>"
+		}
+		if visited[v.Pointer()] {
+			return formatPointer(v, conf)
+		}
+		visited = insertPointer(visited, v.Pointer())
+
+		var ss []string
+		keyConf, valConf := conf, conf
+		keyConf.printType = v.Type().Key().Kind() == reflect.Interface
+		keyConf.followPointers = false
+		valConf.printType = v.Type().Elem().Kind() == reflect.Interface
+		for _, k := range SortKeys(v.MapKeys()) {
+			sk := formatAny(k, keyConf, visited)
+			sv := formatAny(v.MapIndex(k), valConf, visited)
+			ss = append(ss, fmt.Sprintf("%s: %s", sk, sv))
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	case reflect.Struct:
+		var ss []string
+		subConf := conf
+		subConf.printType = true
+		for i := 0; i < v.NumField(); i++ {
+			vv := v.Field(i)
+			if isZero(vv) {
+				continue // Elide zero value fields
+			}
+			name := v.Type().Field(i).Name
+			subConf.UseStringer = conf.UseStringer
+			s := formatAny(vv, subConf, visited)
+			ss = append(ss, fmt.Sprintf("%s: %s", name, s))
+		}
+		s := fmt.Sprintf("{%s}", strings.Join(ss, ", "))
+		if conf.printType {
+			return v.Type().String() + s
+		}
+		return s
+	default:
+		panic(fmt.Sprintf("%v kind not handled", v.Kind()))
+	}
+}
+
+func formatString(s string) string {
+	// Use quoted string if it the same length as a raw string literal.
+	// Otherwise, attempt to use the raw string form.
+	qs := strconv.Quote(s)
+	if len(qs) == 1+len(s)+1 {
+		return qs
+	}
+
+	// Disallow newlines to ensure output is a single line.
+	// Only allow printable runes for readability purposes.
+	rawInvalid := func(r rune) bool {
+		return r == '`' || r == '\n' || !unicode.IsPrint(r)
+	}
+	if strings.IndexFunc(s, rawInvalid) < 0 {
+		return "`" + s + "`"
+	}
+	return qs
+}
+
+func formatPrimitive(t reflect.Type, v interface{}, conf FormatConfig) string {
+	if conf.printType && (conf.PrintPrimitiveType || t.PkgPath() != "") {
+		return fmt.Sprintf("%v(%v)", t, v)
+	}
+	return fmt.Sprintf("%v", v)
+}
+
+func formatPointer(v reflect.Value, conf FormatConfig) string {
+	p := v.Pointer()
+	if !conf.realPointers {
+		p = 0 // For deterministic printing purposes
+	}
+	s := formatHex(uint64(p))
+	if conf.printType {
+		return fmt.Sprintf("(%v)(%s)", v.Type(), s)
+	}
+	return s
+}
+
+func formatHex(u uint64) string {
+	var f string
+	switch {
+	case u <= 0xff:
+		f = "0x%02x"
+	case u <= 0xffff:
+		f = "0x%04x"
+	case u <= 0xffffff:
+		f = "0x%06x"
+	case u <= 0xffffffff:
+		f = "0x%08x"
+	case u <= 0xffffffffff:
+		f = "0x%010x"
+	case u <= 0xffffffffffff:
+		f = "0x%012x"
+	case u <= 0xffffffffffffff:
+		f = "0x%014x"
+	case u <= 0xffffffffffffffff:
+		f = "0x%016x"
+	}
+	return fmt.Sprintf(f, u)
+}
+
+// insertPointer insert p into m, allocating m if necessary.
+func insertPointer(m map[uintptr]bool, p uintptr) map[uintptr]bool {
+	if m == nil {
+		m = make(map[uintptr]bool)
+	}
+	m[p] = true
+	return m
+}
+
+// isZero reports whether v is the zero value.
+// This does not rely on Interface and so can be used on unexported fields.
+func isZero(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Bool:
+		return v.Bool() == false
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Complex64, reflect.Complex128:
+		return v.Complex() == 0
+	case reflect.String:
+		return v.String() == ""
+	case reflect.UnsafePointer:
+		return v.Pointer() == 0
+	case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
+		return v.IsNil()
+	case reflect.Array:
+		for i := 0; i < v.Len(); i++ {
+			if !isZero(v.Index(i)) {
+				return false
+			}
+		}
+		return true
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			if !isZero(v.Field(i)) {
+				return false
+			}
+		}
+		return true
+	}
+	return false
+}
diff --git a/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go b/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go
new file mode 100644
index 0000000..fe8aa27
--- /dev/null
+++ b/vendor/github.com/google/go-cmp/cmp/internal/value/sort.go
@@ -0,0 +1,111 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package value
+
+import (
+	"fmt"
+	"math"
+	"reflect"
+	"sort"
+)
+
+// SortKeys sorts a list of map keys, deduplicating keys if necessary.
+// The type of each value must be comparable.
+func SortKeys(vs []reflect.Value) []reflect.Value {
+	if len(vs) == 0 {
+		return vs
+	}
+
+	// Sort the map keys.
+	sort.Sort(valueSorter(vs))
+
+	// Deduplicate keys (fails for NaNs).
+	vs2 := vs[:1]
+	for _, v := range vs[1:] {
+		if isLess(vs2[len(vs2)-1], v) {
+			vs2 = append(vs2, v)
+		}
+	}
+	return vs2
+}
+
+// TODO: Use sort.Slice once Google AppEngine is on Go1.8 or above.
+type valueSorter []reflect.Value
+
+func (vs valueSorter) Len() int           { return len(vs) }
+func (vs valueSorter) Less(i, j int) bool { return isLess(vs[i], vs[j]) }
+func (vs valueSorter) Swap(i, j int)      { vs[i], vs[j] = vs[j], vs[i] }
+
+// isLess is a generic function for sorting arbitrary map keys.
+// The inputs must be of the same type and must be comparable.
+func isLess(x, y reflect.Value) bool {
+	switch x.Type().Kind() {
+	case reflect.Bool:
+		return !x.Bool() && y.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return x.Int() < y.Int()
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return x.Uint() < y.Uint()
+	case reflect.Float32, reflect.Float64:
+		fx, fy := x.Float(), y.Float()
+		return fx < fy || math.IsNaN(fx) && !math.IsNaN(fy)
+	case reflect.Complex64, reflect.Complex128:
+		cx, cy := x.Complex(), y.Complex()
+		rx, ix, ry, iy := real(cx), imag(cx), real(cy), imag(cy)
+		if rx == ry || (math.IsNaN(rx) && math.IsNaN(ry)) {
+			return ix < iy || math.IsNaN(ix) && !math.IsNaN(iy)
+		}
+		return rx < ry || math.IsNaN(rx) && !math.IsNaN(ry)
+	case reflect.Ptr, reflect.UnsafePointer, reflect.Chan:
+		return x.Pointer() < y.Pointer()
+	case reflect.String:
+		return x.String() < y.String()
+	case reflect.Array:
+		for i := 0; i < x.Len(); i++ {
+			if isLess(x.Index(i), y.Index(i)) {
+				return true
+			}
+			if isLess(y.Index(i), x.Index(i)) {
+				return false
+			}
+		}
+		return false
+	case reflect.Struct:
+		for i := 0; i < x.NumField(); i++ {
+			if isLess(x.Field(i), y.Field(i)) {
+				return true
+			}
+			if isLess(y.Field(i), x.Field(i)) {
+				return false
+			}
+		}
+		return false
+	case reflect.Interface:
+		vx, vy := x.Elem(), y.Elem()
+		if !vx.IsValid() || !vy.IsValid() {
+			return !vx.IsValid() && vy.IsValid()
+		}
+		tx, ty := vx.Type(), vy.Type()
+		if tx == ty {
+			return isLess(x.Elem(), y.Elem())
+		}
+		if tx.Kind() != ty.Kind() {
+			return vx.Kind() < vy.Kind()
+		}
+		if tx.String() != ty.String() {
+			return tx.String() < ty.String()
+		}
+		if tx.PkgPath() != ty.PkgPath() {
+			return tx.PkgPath() < ty.PkgPath()
+		}
+		// This can happen in rare situations, so we fallback to just comparing
+		// the unique pointer for a reflect.Type. This guarantees deterministic
+		// ordering within a program, but it is obviously not stable.
+		return reflect.ValueOf(vx.Type()).Pointer() < reflect.ValueOf(vy.Type()).Pointer()
+	default:
+		// Must be Func, Map, or Slice; which are not comparable.
+		panic(fmt.Sprintf("%T is not comparable", x.Type()))
+	}
+}