diff --git a/go/vendor/github.com/globalsign/mgo/bson/bson_corpus_spec_test_generator.go b/go/vendor/github.com/globalsign/mgo/bson/bson_corpus_spec_test_generator.go
new file mode 100644
index 0000000..3525a00
--- /dev/null
+++ b/go/vendor/github.com/globalsign/mgo/bson/bson_corpus_spec_test_generator.go
@@ -0,0 +1,294 @@
+// +build ignore
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"go/format"
+	"html/template"
+	"io/ioutil"
+	"log"
+	"path/filepath"
+	"strings"
+
+	"github.com/globalsign/mgo/internal/json"
+)
+
+func main() {
+	log.SetFlags(0)
+	log.SetPrefix(name + ": ")
+
+	var g Generator
+
+	fmt.Fprintf(&g, "// Code generated by \"%s.go\"; DO NOT EDIT\n\n", name)
+
+	src := g.generate()
+
+	err := ioutil.WriteFile(fmt.Sprintf("%s.go", strings.TrimSuffix(name, "_generator")), src, 0644)
+	if err != nil {
+		log.Fatalf("writing output: %s", err)
+	}
+}
+
+// Generator holds the state of the analysis. Primarily used to buffer
+// the output for format.Source.
+type Generator struct {
+	bytes.Buffer // Accumulated output.
+}
+
+// format returns the gofmt-ed contents of the Generator's buffer.
+func (g *Generator) format() []byte {
+	src, err := format.Source(g.Bytes())
+	if err != nil {
+		// Should never happen, but can arise when developing this code.
+		// The user can compile the output to see the error.
+		log.Printf("warning: internal error: invalid Go generated: %s", err)
+		log.Printf("warning: compile the package to analyze the error")
+		return g.Bytes()
+	}
+	return src
+}
+
+// EVERYTHING ABOVE IS CONSTANT BETWEEN THE GENERATORS
+
+const name = "bson_corpus_spec_test_generator"
+
+func (g *Generator) generate() []byte {
+
+	testFiles, err := filepath.Glob("./specdata/specifications/source/bson-corpus/tests/*.json")
+	if err != nil {
+		log.Fatalf("error reading bson-corpus files: %s", err)
+	}
+
+	tests, err := g.loadTests(testFiles)
+	if err != nil {
+		log.Fatalf("error loading tests: %s", err)
+	}
+
+	tmpl, err := g.getTemplate()
+	if err != nil {
+		log.Fatalf("error loading template: %s", err)
+	}
+
+	tmpl.Execute(&g.Buffer, tests)
+
+	return g.format()
+}
+
+func (g *Generator) loadTests(filenames []string) ([]*testDef, error) {
+	var tests []*testDef
+	for _, filename := range filenames {
+		test, err := g.loadTest(filename)
+		if err != nil {
+			return nil, err
+		}
+
+		tests = append(tests, test)
+	}
+
+	return tests, nil
+}
+
+func (g *Generator) loadTest(filename string) (*testDef, error) {
+	content, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+
+	var testDef testDef
+	err = json.Unmarshal(content, &testDef)
+	if err != nil {
+		return nil, err
+	}
+
+	names := make(map[string]struct{})
+
+	for i := len(testDef.Valid) - 1; i >= 0; i-- {
+		if testDef.BsonType == "0x05" && testDef.Valid[i].Description == "subtype 0x02" {
+			testDef.Valid = append(testDef.Valid[:i], testDef.Valid[i+1:]...)
+			continue
+		}
+
+		name := cleanupFuncName(testDef.Description + "_" + testDef.Valid[i].Description)
+		nameIdx := name
+		j := 1
+		for {
+			if _, ok := names[nameIdx]; !ok {
+				break
+			}
+
+			nameIdx = fmt.Sprintf("%s_%d", name, j)
+		}
+
+		names[nameIdx] = struct{}{}
+
+		testDef.Valid[i].TestDef = &testDef
+		testDef.Valid[i].Name = nameIdx
+		testDef.Valid[i].StructTest = testDef.TestKey != "" &&
+			(testDef.BsonType != "0x05" || strings.Contains(testDef.Valid[i].Description, "0x00")) &&
+			!testDef.Deprecated
+	}
+
+	for i := len(testDef.DecodeErrors) - 1; i >= 0; i-- {
+		if strings.Contains(testDef.DecodeErrors[i].Description, "UTF-8") {
+			testDef.DecodeErrors = append(testDef.DecodeErrors[:i], testDef.DecodeErrors[i+1:]...)
+			continue
+		}
+
+		name := cleanupFuncName(testDef.Description + "_" + testDef.DecodeErrors[i].Description)
+		nameIdx := name
+		j := 1
+		for {
+			if _, ok := names[nameIdx]; !ok {
+				break
+			}
+
+			nameIdx = fmt.Sprintf("%s_%d", name, j)
+		}
+		names[nameIdx] = struct{}{}
+
+		testDef.DecodeErrors[i].Name = nameIdx
+	}
+
+	return &testDef, nil
+}
+
+func (g *Generator) getTemplate() (*template.Template, error) {
+	content := `package bson_test
+
+import (
+    "encoding/hex"
+	"time"
+
+	. "gopkg.in/check.v1"
+    "github.com/globalsign/mgo/bson"
+)
+
+func testValid(c *C, in []byte, expected []byte, result interface{}) {
+	err := bson.Unmarshal(in, result)
+	c.Assert(err, IsNil)
+
+	out, err := bson.Marshal(result)
+	c.Assert(err, IsNil)
+
+	c.Assert(string(expected), Equals, string(out), Commentf("roundtrip failed for %T, expected '%x' but got '%x'", result, expected, out))
+}
+
+func testDecodeSkip(c *C, in []byte) {
+	err := bson.Unmarshal(in, &struct{}{})
+	c.Assert(err, IsNil)
+}
+
+func testDecodeError(c *C, in []byte, result interface{}) {
+	err := bson.Unmarshal(in, result)
+	c.Assert(err, Not(IsNil))
+}
+
+{{range .}}
+{{range .Valid}}
+func (s *S) Test{{.Name}}(c *C) {
+    b, err := hex.DecodeString("{{.Bson}}")
+	c.Assert(err, IsNil)
+
+    {{if .CanonicalBson}}
+    cb, err := hex.DecodeString("{{.CanonicalBson}}")
+	c.Assert(err, IsNil)
+	{{else}}
+    cb := b
+    {{end}}
+
+    var resultD bson.D
+	testValid(c, b, cb, &resultD)
+	{{if .StructTest}}var resultS struct {
+		Element {{.TestDef.GoType}} ` + "`bson:\"{{.TestDef.TestKey}}\"`" + `
+	}
+	testValid(c, b, cb, &resultS){{end}}
+
+	testDecodeSkip(c, b)
+}
+{{end}}
+
+{{range .DecodeErrors}}
+func (s *S) Test{{.Name}}(c *C) {
+	b, err := hex.DecodeString("{{.Bson}}")
+	c.Assert(err, IsNil)
+
+	var resultD bson.D
+	testDecodeError(c, b, &resultD)
+}
+{{end}}
+{{end}}
+`
+	tmpl, err := template.New("").Parse(content)
+	if err != nil {
+		return nil, err
+	}
+	return tmpl, nil
+}
+
+func cleanupFuncName(name string) string {
+	return strings.Map(func(r rune) rune {
+		if (r >= 48 && r <= 57) || (r >= 65 && r <= 90) || (r >= 97 && r <= 122) {
+			return r
+		}
+		return '_'
+	}, name)
+}
+
+type testDef struct {
+	Description  string         `json:"description"`
+	BsonType     string         `json:"bson_type"`
+	TestKey      string         `json:"test_key"`
+	Valid        []*valid       `json:"valid"`
+	DecodeErrors []*decodeError `json:"decodeErrors"`
+	Deprecated   bool           `json:"deprecated"`
+}
+
+func (t *testDef) GoType() string {
+	switch t.BsonType {
+	case "0x01":
+		return "float64"
+	case "0x02":
+		return "string"
+	case "0x03":
+		return "bson.D"
+	case "0x04":
+		return "[]interface{}"
+	case "0x05":
+		return "[]byte"
+	case "0x07":
+		return "bson.ObjectId"
+	case "0x08":
+		return "bool"
+	case "0x09":
+		return "time.Time"
+	case "0x0E":
+		return "string"
+	case "0x10":
+		return "int32"
+	case "0x12":
+		return "int64"
+	case "0x13":
+		return "bson.Decimal"
+	default:
+		return "interface{}"
+	}
+}
+
+type valid struct {
+	Description   string `json:"description"`
+	Bson          string `json:"bson"`
+	CanonicalBson string `json:"canonical_bson"`
+
+	Name       string
+	StructTest bool
+	TestDef    *testDef
+}
+
+type decodeError struct {
+	Description string `json:"description"`
+	Bson        string `json:"bson"`
+
+	Name string
+}