diff --git a/cio/io_test.go b/cio/io_test.go
index e42836f76..1ca951c16 100644
--- a/cio/io_test.go
+++ b/cio/io_test.go
@@ -33,8 +33,8 @@ import (
 
 	"github.com/containerd/fifo"
 	"github.com/google/go-cmp/cmp/cmpopts"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 func assertHasPrefix(t *testing.T, s, prefix string) {
diff --git a/cio/io_unix_test.go b/cio/io_unix_test.go
index fc2cce96d..58412d71f 100644
--- a/cio/io_unix_test.go
+++ b/cio/io_unix_test.go
@@ -23,7 +23,7 @@ import (
 	"path/filepath"
 	"testing"
 
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestOpenFifos(t *testing.T) {
diff --git a/cio/io_windows_test.go b/cio/io_windows_test.go
index e0191480e..92fa1ff1c 100644
--- a/cio/io_windows_test.go
+++ b/cio/io_windows_test.go
@@ -21,7 +21,7 @@ package cio
 import (
 	"testing"
 
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestNewFifoSetInDir_NoTerminal(t *testing.T) {
diff --git a/client_ttrpc_test.go b/client_ttrpc_test.go
index b12da5f27..85b7aa383 100644
--- a/client_ttrpc_test.go
+++ b/client_ttrpc_test.go
@@ -26,7 +26,7 @@ import (
 	"github.com/containerd/containerd/pkg/ttrpcutil"
 	"github.com/containerd/ttrpc"
 	"github.com/gogo/protobuf/types"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestClientTTRPC_New(t *testing.T) {
diff --git a/content/helpers_test.go b/content/helpers_test.go
index 95079a9a6..1b4e39926 100644
--- a/content/helpers_test.go
+++ b/content/helpers_test.go
@@ -26,8 +26,8 @@ import (
 
 	"github.com/containerd/containerd/errdefs"
 	"github.com/opencontainers/go-digest"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 type copySource struct {
diff --git a/content/local/store_test.go b/content/local/store_test.go
index 86e284a77..559bdab99 100644
--- a/content/local/store_test.go
+++ b/content/local/store_test.go
@@ -40,7 +40,7 @@ import (
 
 	"github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 type memoryLabelStore struct {
diff --git a/content/testsuite/testsuite.go b/content/testsuite/testsuite.go
index 3e1a90ddf..8264f6274 100644
--- a/content/testsuite/testsuite.go
+++ b/content/testsuite/testsuite.go
@@ -36,7 +36,7 @@ import (
 	digest "github.com/opencontainers/go-digest"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 const (
diff --git a/gc/scheduler/scheduler_test.go b/gc/scheduler/scheduler_test.go
index 8027d993a..3690b78db 100644
--- a/gc/scheduler/scheduler_test.go
+++ b/gc/scheduler/scheduler_test.go
@@ -23,7 +23,7 @@ import (
 	"time"
 
 	"github.com/containerd/containerd/gc"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestPauseThreshold(t *testing.T) {
diff --git a/log/context_test.go b/log/context_test.go
index c5da476fa..0d9827c6d 100644
--- a/log/context_test.go
+++ b/log/context_test.go
@@ -20,7 +20,7 @@ import (
 	"context"
 	"testing"
 
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestLoggerContext(t *testing.T) {
diff --git a/mount/lookup_linux_test.go b/mount/lookup_linux_test.go
index e9347566e..f2ca5fd43 100644
--- a/mount/lookup_linux_test.go
+++ b/mount/lookup_linux_test.go
@@ -31,7 +31,7 @@ import (
 	// so we use continuity/testutil instead.
 	"github.com/containerd/continuity/testutil"
 	"github.com/containerd/continuity/testutil/loopback"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func checkLookup(t *testing.T, fsType, mntPoint, dir string) {
diff --git a/pkg/testutil/helpers_unix.go b/pkg/testutil/helpers_unix.go
index 96dd92eac..eee004af8 100644
--- a/pkg/testutil/helpers_unix.go
+++ b/pkg/testutil/helpers_unix.go
@@ -24,7 +24,7 @@ import (
 	"testing"
 
 	"github.com/containerd/containerd/mount"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 // Unmount unmounts a given mountPoint and sets t.Error if it fails
diff --git a/remotes/docker/fetcher_test.go b/remotes/docker/fetcher_test.go
index 92a308378..5930ec614 100644
--- a/remotes/docker/fetcher_test.go
+++ b/remotes/docker/fetcher_test.go
@@ -29,7 +29,7 @@ import (
 	"testing"
 
 	"github.com/pkg/errors"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 func TestFetcherOpen(t *testing.T) {
diff --git a/remotes/docker/scope_test.go b/remotes/docker/scope_test.go
index 2ec0feebd..e9995a6a4 100644
--- a/remotes/docker/scope_test.go
+++ b/remotes/docker/scope_test.go
@@ -21,8 +21,8 @@ import (
 	"testing"
 
 	"github.com/containerd/containerd/reference"
-	"gotest.tools/assert"
-	"gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	"gotest.tools/v3/assert/cmp"
 )
 
 func TestRepositoryScope(t *testing.T) {
diff --git a/services/server/config/config_test.go b/services/server/config/config_test.go
index 3091abc5d..47a12f17b 100644
--- a/services/server/config/config_test.go
+++ b/services/server/config/config_test.go
@@ -23,7 +23,7 @@ import (
 	"sort"
 	"testing"
 
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 
 	"github.com/containerd/containerd/plugin"
 )
diff --git a/services/server/server_test.go b/services/server/server_test.go
index 8a3b6b88c..a7b1a144f 100644
--- a/services/server/server_test.go
+++ b/services/server/server_test.go
@@ -20,8 +20,8 @@ import (
 	"testing"
 
 	srvconfig "github.com/containerd/containerd/services/server/config"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 func TestCreateTopLevelDirectoriesErrorsWithSamePathForRootAndState(t *testing.T) {
diff --git a/snapshots/benchsuite/benchmark_test.go b/snapshots/benchsuite/benchmark_test.go
index 05e3a183a..40514d54d 100644
--- a/snapshots/benchsuite/benchmark_test.go
+++ b/snapshots/benchsuite/benchmark_test.go
@@ -32,7 +32,7 @@ import (
 	"github.com/containerd/continuity/fs/fstest"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/snapshots"
diff --git a/snapshots/devmapper/config_test.go b/snapshots/devmapper/config_test.go
index b6b9cde2f..bae0ed616 100644
--- a/snapshots/devmapper/config_test.go
+++ b/snapshots/devmapper/config_test.go
@@ -25,8 +25,8 @@ import (
 
 	"github.com/BurntSushi/toml"
 	"github.com/hashicorp/go-multierror"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 func TestLoadConfig(t *testing.T) {
diff --git a/snapshots/devmapper/dmsetup/dmsetup_test.go b/snapshots/devmapper/dmsetup/dmsetup_test.go
index 97fdeb9b1..3b4c688bb 100644
--- a/snapshots/devmapper/dmsetup/dmsetup_test.go
+++ b/snapshots/devmapper/dmsetup/dmsetup_test.go
@@ -26,8 +26,8 @@ import (
 
 	"github.com/docker/go-units"
 	"golang.org/x/sys/unix"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 
 	"github.com/containerd/containerd/pkg/testutil"
 	"github.com/containerd/containerd/snapshots/devmapper/losetup"
diff --git a/snapshots/devmapper/losetup/losetup_test.go b/snapshots/devmapper/losetup/losetup_test.go
index 773ee59ca..b6d2d5ebc 100644
--- a/snapshots/devmapper/losetup/losetup_test.go
+++ b/snapshots/devmapper/losetup/losetup_test.go
@@ -25,8 +25,8 @@ import (
 
 	"github.com/docker/go-units"
 	"golang.org/x/sys/unix"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 
 	"github.com/containerd/containerd/pkg/testutil"
 )
diff --git a/snapshots/devmapper/metadata_test.go b/snapshots/devmapper/metadata_test.go
index fe62d206c..1b475c7d5 100644
--- a/snapshots/devmapper/metadata_test.go
+++ b/snapshots/devmapper/metadata_test.go
@@ -28,8 +28,8 @@ import (
 
 	"github.com/pkg/errors"
 	"go.etcd.io/bbolt"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 var (
diff --git a/snapshots/devmapper/pool_device_test.go b/snapshots/devmapper/pool_device_test.go
index 49eef4089..7ee7301ef 100644
--- a/snapshots/devmapper/pool_device_test.go
+++ b/snapshots/devmapper/pool_device_test.go
@@ -34,7 +34,7 @@ import (
 	"github.com/containerd/containerd/snapshots/devmapper/losetup"
 	"github.com/docker/go-units"
 	"github.com/sirupsen/logrus"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 )
 
 const (
diff --git a/snapshots/devmapper/snapshotter_test.go b/snapshots/devmapper/snapshotter_test.go
index 1ecde0528..5157be869 100644
--- a/snapshots/devmapper/snapshotter_test.go
+++ b/snapshots/devmapper/snapshotter_test.go
@@ -30,7 +30,7 @@ import (
 	"github.com/containerd/continuity/fs/fstest"
 	"github.com/hashicorp/go-multierror"
 	"github.com/sirupsen/logrus"
-	"gotest.tools/assert"
+	"gotest.tools/v3/assert"
 
 	"github.com/containerd/containerd/mount"
 	"github.com/containerd/containerd/namespaces"
diff --git a/snapshots/storage/metastore_test.go b/snapshots/storage/metastore_test.go
index a2b7e4ca6..90ed2ae73 100644
--- a/snapshots/storage/metastore_test.go
+++ b/snapshots/storage/metastore_test.go
@@ -28,8 +28,8 @@ import (
 	"github.com/containerd/containerd/snapshots"
 	"github.com/google/go-cmp/cmp"
 	"github.com/pkg/errors"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 type testFunc func(context.Context, *testing.T, *MetaStore)
diff --git a/snapshots/testsuite/testsuite.go b/snapshots/testsuite/testsuite.go
index c5af695f0..b2434025f 100644
--- a/snapshots/testsuite/testsuite.go
+++ b/snapshots/testsuite/testsuite.go
@@ -34,8 +34,8 @@ import (
 	"github.com/containerd/containerd/pkg/testutil"
 	"github.com/containerd/containerd/snapshots"
 	"github.com/containerd/continuity/fs/fstest"
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 // SnapshotterFunc is used in SnapshotterSuite
diff --git a/sys/oom_unix_test.go b/sys/oom_unix_test.go
index f849c64ec..dee5f81bf 100644
--- a/sys/oom_unix_test.go
+++ b/sys/oom_unix_test.go
@@ -25,8 +25,8 @@ import (
 	"testing"
 	"time"
 
-	"gotest.tools/assert"
-	is "gotest.tools/assert/cmp"
+	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 )
 
 func TestSetPositiveOomScoreAdjustment(t *testing.T) {
diff --git a/vendor.conf b/vendor.conf
index 5478e850d..162bc8ba6 100644
--- a/vendor.conf
+++ b/vendor.conf
@@ -50,7 +50,7 @@ golang.org/x/sys                                    c990c680b611ac1aeb7d8f2af94a
 golang.org/x/text                                   19e51611da83d6be54ddafce4a4af510cb3e9ea4
 google.golang.org/genproto                          e50cd9704f63023d62cd06a1994b98227fc4d21a
 google.golang.org/grpc                              f495f5b15ae7ccda3b38c53a1bfcde4c1a58a2bc # v1.27.1
-gotest.tools                                        1083505acf35a0bd8a696b26837e1fb3187a7a83 # v2.3.0
+gotest.tools/v3                                     bb0d8a963040ea5048dcef1a14d8f8b58a33d4b3 # v3.0.2
 
 # cri dependencies
 github.com/containerd/cri                           c0294ebfe0b4342db85c0faf7727ceb8d8c3afce # master
diff --git a/vendor/gotest.tools/go.mod b/vendor/gotest.tools/go.mod
deleted file mode 100644
index 39d0a1a77..000000000
--- a/vendor/gotest.tools/go.mod
+++ /dev/null
@@ -1,8 +0,0 @@
-module gotest.tools
-
-require (
-	github.com/google/go-cmp v0.2.0
-	github.com/pkg/errors v0.8.0
-	github.com/spf13/pflag v1.0.3
-	golang.org/x/tools v0.0.0-20180810170437-e96c4e24768d
-)
diff --git a/vendor/gotest.tools/LICENSE b/vendor/gotest.tools/v3/LICENSE
similarity index 100%
rename from vendor/gotest.tools/LICENSE
rename to vendor/gotest.tools/v3/LICENSE
diff --git a/vendor/gotest.tools/README.md b/vendor/gotest.tools/v3/README.md
similarity index 68%
rename from vendor/gotest.tools/README.md
rename to vendor/gotest.tools/v3/README.md
index 3155723dd..56b3e4ad2 100644
--- a/vendor/gotest.tools/README.md
+++ b/vendor/gotest.tools/v3/README.md
@@ -2,26 +2,41 @@
 
 A collection of packages to augment `testing` and support common patterns.
 
-[![GoDoc](https://godoc.org/gotest.tools?status.svg)](https://godoc.org/gotest.tools)
+[![GoDoc](https://godoc.org/gotest.tools?status.svg)](http://gotest.tools)
 [![CircleCI](https://circleci.com/gh/gotestyourself/gotest.tools/tree/master.svg?style=shield)](https://circleci.com/gh/gotestyourself/gotest.tools/tree/master)
 [![Go Reportcard](https://goreportcard.com/badge/gotest.tools)](https://goreportcard.com/report/gotest.tools)
 
+## Usage
+
+With Go modules enabled (go1.11+)
+
+```
+$ go get gotest.tools/v3
+```
+
+```
+import "gotest.tools/v3/assert"
+```
+
+To use `gotest.tools` with an older version of Go that does not understand Go
+module paths pin to version `v2.3.0`.
+
 
 ## Packages
 
-* [assert](http://godoc.org/gotest.tools/assert) -
+* [assert](http://gotest.tools/assert) -
   compare values and fail the test when a comparison fails
-* [env](http://godoc.org/gotest.tools/env) -
+* [env](http://gotest.tools/env) -
   test code which uses environment variables
-* [fs](http://godoc.org/gotest.tools/fs) -
+* [fs](http://gotest.tools/fs) -
   create temporary files and compare a filesystem tree to an expected value
-* [golden](http://godoc.org/gotest.tools/golden) -
+* [golden](http://gotest.tools/golden) -
   compare large multi-line strings against values frozen in golden files
-* [icmd](http://godoc.org/gotest.tools/icmd) -
+* [icmd](http://gotest.tools/icmd) -
   execute binaries and test the output
-* [poll](http://godoc.org/gotest.tools/poll) -
+* [poll](http://gotest.tools/poll) -
   test asynchronous code by polling until a desired state is reached
-* [skip](http://godoc.org/gotest.tools/skip) -
+* [skip](http://gotest.tools/skip) -
   skip a test and print the source code of the condition used to skip the test
 
 ## Related
diff --git a/vendor/gotest.tools/assert/assert.go b/vendor/gotest.tools/v3/assert/assert.go
similarity index 79%
rename from vendor/gotest.tools/assert/assert.go
rename to vendor/gotest.tools/v3/assert/assert.go
index 05d663543..e75d1f38a 100644
--- a/vendor/gotest.tools/assert/assert.go
+++ b/vendor/gotest.tools/v3/assert/assert.go
@@ -49,30 +49,31 @@ The example below shows assert used with some common types.
 
 Comparisons
 
-Package https://godoc.org/gotest.tools/assert/cmp provides
+Package http://gotest.tools/assert/cmp provides
 many common comparisons. Additional comparisons can be written to compare
 values in other ways. See the example Assert (CustomComparison).
 
 Automated migration from testify
 
-gty-migrate-from-testify is a binary which can update source code which uses
-testify assertions to use the assertions provided by this package.
+gty-migrate-from-testify is a command which translates Go source code from
+testify assertions to the assertions provided by this package.
 
-See http://bit.do/cmd-gty-migrate-from-testify.
+See http://gotest.tools/assert/cmd/gty-migrate-from-testify.
 
 
 */
-package assert // import "gotest.tools/assert"
+package assert // import "gotest.tools/v3/assert"
 
 import (
 	"fmt"
 	"go/ast"
 	"go/token"
+	"reflect"
 
 	gocmp "github.com/google/go-cmp/cmp"
-	"gotest.tools/assert/cmp"
-	"gotest.tools/internal/format"
-	"gotest.tools/internal/source"
+	"gotest.tools/v3/assert/cmp"
+	"gotest.tools/v3/internal/format"
+	"gotest.tools/v3/internal/source"
 )
 
 // BoolOrComparison can be a bool, or cmp.Comparison. See Assert() for usage.
@@ -118,8 +119,8 @@ func assert(
 		return true
 
 	case error:
-		msg := "error is not nil: "
-		t.Log(format.WithCustomMessage(failureMessage+msg+check.Error(), msgAndArgs...))
+		msg := failureMsgFromError(check)
+		t.Log(format.WithCustomMessage(failureMessage+msg, msgAndArgs...))
 
 	case cmp.Comparison:
 		success = runComparison(t, argSelector, check, msgAndArgs...)
@@ -174,6 +175,15 @@ func logFailureFromBool(t TestingT, msgAndArgs ...interface{}) {
 	t.Log(format.WithCustomMessage(failureMessage+msg, msgAndArgs...))
 }
 
+func failureMsgFromError(err error) string {
+	// Handle errors with non-nil types
+	v := reflect.ValueOf(err)
+	if v.Kind() == reflect.Ptr && v.IsNil() {
+		return fmt.Sprintf("error is not nil: error has type %T", err)
+	}
+	return "error is not nil: " + err.Error()
+}
+
 func boolFailureMessage(expr ast.Expr) (string, error) {
 	if binaryExpr, ok := expr.(*ast.BinaryExpr); ok && binaryExpr.Op == token.NEQ {
 		x, err := source.FormatNode(binaryExpr.X)
@@ -202,17 +212,20 @@ func boolFailureMessage(expr ast.Expr) (string, error) {
 	return "expression is false: " + formatted, nil
 }
 
-// Assert performs a comparison. If the comparison fails the test is marked as
+// Assert performs a comparison. If the comparison fails, the test is marked as
 // failed, a failure message is logged, and execution is stopped immediately.
 //
-// The comparison argument may be one of three types: bool, cmp.Comparison or
-// error.
-// When called with a bool the failure message will contain the literal source
-// code of the expression.
-// When called with a cmp.Comparison the comparison is responsible for producing
-// a helpful failure message.
-// When called with an error a nil value is considered success. A non-nil error
-// is a failure, and Error() is used as the failure message.
+// The comparison argument may be one of three types:
+//   bool
+// True is success. False is a failure.
+// The failure message will contain the literal source code of the expression.
+//   cmp.Comparison
+// Uses cmp.Result.Success() to check for success of failure.
+// The comparison is responsible for producing a helpful failure message.
+// http://gotest.tools/assert/cmp provides many common comparisons.
+//   error
+// A nil value is considered success.
+// A non-nil error is a failure, err.Error() is used as the failure message.
 func Assert(t TestingT, comparison BoolOrComparison, msgAndArgs ...interface{}) {
 	if ht, ok := t.(helperT); ok {
 		ht.Helper()
@@ -260,10 +273,10 @@ func Equal(t TestingT, x, y interface{}, msgAndArgs ...interface{}) {
 	assert(t, t.FailNow, argsAfterT, cmp.Equal(x, y), msgAndArgs...)
 }
 
-// DeepEqual uses google/go-cmp (http://bit.do/go-cmp) to assert two values are
-// equal and fails the test if they are not equal.
+// DeepEqual uses google/go-cmp (https://godoc.org/github.com/google/go-cmp/cmp)
+// to assert two values are equal and fails the test if they are not equal.
 //
-// Package https://godoc.org/gotest.tools/assert/opt provides some additional
+// Package http://gotest.tools/assert/opt provides some additional
 // commonly used Options.
 //
 // This is equivalent to Assert(t, cmp.DeepEqual(x, y)).
@@ -295,14 +308,19 @@ func ErrorContains(t TestingT, err error, substring string, msgAndArgs ...interf
 }
 
 // ErrorType fails the test if err is nil, or err is not the expected type.
+// Equivalent to Assert(t, cmp.ErrorType(err, expected)).
 //
 // Expected can be one of:
-// a func(error) bool which returns true if the error is the expected type,
-// an instance of (or a pointer to) a struct of the expected type,
-// a pointer to an interface the error is expected to implement,
-// a reflect.Type of the expected struct or interface.
-//
-// Equivalent to Assert(t, cmp.ErrorType(err, expected)).
+//   func(error) bool
+// Function should return true if the error is the expected type.
+//   type struct{}, type &struct{}
+// A struct or a pointer to a struct.
+// Fails if the error is not of the same type as expected.
+//   type &interface{}
+// A pointer to an interface type.
+// Fails if err does not implement the interface.
+//   reflect.Type
+// Fails if err does not implement the reflect.Type
 func ErrorType(t TestingT, err error, expected interface{}, msgAndArgs ...interface{}) {
 	if ht, ok := t.(helperT); ok {
 		ht.Helper()
diff --git a/vendor/gotest.tools/assert/cmp/compare.go b/vendor/gotest.tools/v3/assert/cmp/compare.go
similarity index 92%
rename from vendor/gotest.tools/assert/cmp/compare.go
rename to vendor/gotest.tools/v3/assert/cmp/compare.go
index cf48d887a..bb3b24f43 100644
--- a/vendor/gotest.tools/assert/cmp/compare.go
+++ b/vendor/gotest.tools/v3/assert/cmp/compare.go
@@ -1,5 +1,5 @@
 /*Package cmp provides Comparisons for Assert and Check*/
-package cmp // import "gotest.tools/assert/cmp"
+package cmp // import "gotest.tools/v3/assert/cmp"
 
 import (
 	"fmt"
@@ -8,7 +8,7 @@ import (
 	"strings"
 
 	"github.com/google/go-cmp/cmp"
-	"gotest.tools/internal/format"
+	"gotest.tools/v3/internal/format"
 )
 
 // Comparison is a function which compares values and returns ResultSuccess if
@@ -16,11 +16,12 @@ import (
 // Result will contain a message about why it failed.
 type Comparison func() Result
 
-// DeepEqual compares two values using google/go-cmp (http://bit.do/go-cmp)
+// DeepEqual compares two values using google/go-cmp
+// (https://godoc.org/github.com/google/go-cmp/cmp)
 // and succeeds if the values are equal.
 //
 // The comparison can be customized using comparison Options.
-// Package https://godoc.org/gotest.tools/assert/opt provides some additional
+// Package http://gotest.tools/assert/opt provides some additional
 // commonly used Options.
 func DeepEqual(x, y interface{}, opts ...cmp.Option) Comparison {
 	return func() (result Result) {
@@ -103,10 +104,10 @@ func Equal(x, y interface{}) Comparison {
 			return multiLineDiffResult(diff)
 		}
 		return ResultFailureTemplate(`
-			{{- .Data.x}} (
+			{{- printf "%v" .Data.x}} (
 				{{- with callArg 0 }}{{ formatNode . }} {{end -}}
 				{{- printf "%T" .Data.x -}}
-			) != {{ .Data.y}} (
+			) != {{ printf "%v" .Data.y}} (
 				{{- with callArg 1 }}{{ formatNode . }} {{end -}}
 				{{- printf "%T" .Data.y -}}
 			)`,
@@ -241,10 +242,12 @@ func ErrorContains(err error, substring string) Comparison {
 	}
 }
 
+type causer interface {
+	Cause() error
+}
+
 func formatErrorMessage(err error) string {
-	if _, ok := err.(interface {
-		Cause() error
-	}); ok {
+	if _, ok := err.(causer); ok {
 		return fmt.Sprintf("%q\n%+v", err, err)
 	}
 	// This error was not wrapped with github.com/pkg/errors
@@ -283,10 +286,16 @@ func isNil(obj interface{}, msgFunc func(reflect.Value) string) Comparison {
 // ErrorType succeeds if err is not nil and is of the expected type.
 //
 // Expected can be one of:
-// a func(error) bool which returns true if the error is the expected type,
-// an instance of (or a pointer to) a struct of the expected type,
-// a pointer to an interface the error is expected to implement,
-// a reflect.Type of the expected struct or interface.
+//   func(error) bool
+// Function should return true if the error is the expected type.
+//   type struct{}, type &struct{}
+// A struct or a pointer to a struct.
+// Fails if the error is not of the same type as expected.
+//   type &interface{}
+// A pointer to an interface type.
+// Fails if err does not implement the interface.
+//   reflect.Type
+// Fails if err does not implement the reflect.Type
 func ErrorType(err error, expected interface{}) Comparison {
 	return func() Result {
 		switch expectedType := expected.(type) {
diff --git a/vendor/gotest.tools/assert/cmp/result.go b/vendor/gotest.tools/v3/assert/cmp/result.go
similarity index 98%
rename from vendor/gotest.tools/assert/cmp/result.go
rename to vendor/gotest.tools/v3/assert/cmp/result.go
index 204edda4b..385e1a087 100644
--- a/vendor/gotest.tools/assert/cmp/result.go
+++ b/vendor/gotest.tools/v3/assert/cmp/result.go
@@ -6,7 +6,7 @@ import (
 	"go/ast"
 	"text/template"
 
-	"gotest.tools/internal/source"
+	"gotest.tools/v3/internal/source"
 )
 
 // A Result of a Comparison.
diff --git a/vendor/gotest.tools/assert/result.go b/vendor/gotest.tools/v3/assert/result.go
similarity index 95%
rename from vendor/gotest.tools/assert/result.go
rename to vendor/gotest.tools/v3/assert/result.go
index 949d93961..d77860b58 100644
--- a/vendor/gotest.tools/assert/result.go
+++ b/vendor/gotest.tools/v3/assert/result.go
@@ -4,9 +4,9 @@ import (
 	"fmt"
 	"go/ast"
 
-	"gotest.tools/assert/cmp"
-	"gotest.tools/internal/format"
-	"gotest.tools/internal/source"
+	"gotest.tools/v3/assert/cmp"
+	"gotest.tools/v3/internal/format"
+	"gotest.tools/v3/internal/source"
 )
 
 func runComparison(
diff --git a/vendor/gotest.tools/v3/go.mod b/vendor/gotest.tools/v3/go.mod
new file mode 100644
index 000000000..4ae9354e5
--- /dev/null
+++ b/vendor/gotest.tools/v3/go.mod
@@ -0,0 +1,10 @@
+module gotest.tools/v3
+
+require (
+	github.com/google/go-cmp v0.3.0
+	github.com/pkg/errors v0.8.1
+	github.com/spf13/pflag v1.0.3
+	golang.org/x/tools v0.0.0-20190624222133-a101b041ded4
+)
+
+go 1.11
diff --git a/vendor/gotest.tools/internal/difflib/LICENSE b/vendor/gotest.tools/v3/internal/difflib/LICENSE
similarity index 100%
rename from vendor/gotest.tools/internal/difflib/LICENSE
rename to vendor/gotest.tools/v3/internal/difflib/LICENSE
diff --git a/vendor/gotest.tools/internal/difflib/difflib.go b/vendor/gotest.tools/v3/internal/difflib/difflib.go
similarity index 99%
rename from vendor/gotest.tools/internal/difflib/difflib.go
rename to vendor/gotest.tools/v3/internal/difflib/difflib.go
index b6f486b9c..9bf506b6b 100644
--- a/vendor/gotest.tools/internal/difflib/difflib.go
+++ b/vendor/gotest.tools/v3/internal/difflib/difflib.go
@@ -4,7 +4,7 @@ Original source: https://github.com/pmezard/go-difflib
 
 This file is trimmed to only the parts used by this repository.
 */
-package difflib // import "gotest.tools/internal/difflib"
+package difflib // import "gotest.tools/v3/internal/difflib"
 
 func min(a, b int) int {
 	if a < b {
diff --git a/vendor/gotest.tools/internal/format/diff.go b/vendor/gotest.tools/v3/internal/format/diff.go
similarity index 99%
rename from vendor/gotest.tools/internal/format/diff.go
rename to vendor/gotest.tools/v3/internal/format/diff.go
index c938c97be..9897d4b9d 100644
--- a/vendor/gotest.tools/internal/format/diff.go
+++ b/vendor/gotest.tools/v3/internal/format/diff.go
@@ -6,7 +6,7 @@ import (
 	"strings"
 	"unicode"
 
-	"gotest.tools/internal/difflib"
+	"gotest.tools/v3/internal/difflib"
 )
 
 const (
diff --git a/vendor/gotest.tools/internal/format/format.go b/vendor/gotest.tools/v3/internal/format/format.go
similarity index 91%
rename from vendor/gotest.tools/internal/format/format.go
rename to vendor/gotest.tools/v3/internal/format/format.go
index 8f6494f99..5097e4bd6 100644
--- a/vendor/gotest.tools/internal/format/format.go
+++ b/vendor/gotest.tools/v3/internal/format/format.go
@@ -1,4 +1,4 @@
-package format // import "gotest.tools/internal/format"
+package format // import "gotest.tools/v3/internal/format"
 
 import "fmt"
 
diff --git a/vendor/gotest.tools/internal/source/defers.go b/vendor/gotest.tools/v3/internal/source/defers.go
similarity index 100%
rename from vendor/gotest.tools/internal/source/defers.go
rename to vendor/gotest.tools/v3/internal/source/defers.go
diff --git a/vendor/gotest.tools/internal/source/source.go b/vendor/gotest.tools/v3/internal/source/source.go
similarity index 91%
rename from vendor/gotest.tools/internal/source/source.go
rename to vendor/gotest.tools/v3/internal/source/source.go
index 8a5d0e8d3..134afb6ba 100644
--- a/vendor/gotest.tools/internal/source/source.go
+++ b/vendor/gotest.tools/v3/internal/source/source.go
@@ -1,4 +1,4 @@
-package source // import "gotest.tools/internal/source"
+package source // import "gotest.tools/v3/internal/source"
 
 import (
 	"bytes"
@@ -92,7 +92,9 @@ func nodePosition(fileset *token.FileSet, node ast.Node) token.Position {
 	return fileset.Position(node.Pos())
 }
 
-var goVersionBefore19 = func() bool {
+// GoVersionLessThan returns true if runtime.Version() is semantically less than
+// version 1.minor.
+func GoVersionLessThan(minor int64) bool {
 	version := runtime.Version()
 	// not a release version
 	if !strings.HasPrefix(version, "go") {
@@ -103,9 +105,11 @@ var goVersionBefore19 = func() bool {
 	if len(parts) < 2 {
 		return false
 	}
-	minor, err := strconv.ParseInt(parts[1], 10, 32)
-	return err == nil && parts[0] == "1" && minor < 9
-}()
+	actual, err := strconv.ParseInt(parts[1], 10, 32)
+	return err == nil && parts[0] == "1" && actual < minor
+}
+
+var goVersionBefore19 = GoVersionLessThan(9)
 
 func getCallExprArgs(node ast.Node) ([]ast.Expr, error) {
 	visitor := &callExprVisitor{}