diff --git a/container_test.go b/container_test.go
index a2627114c..0c0d8416c 100644
--- a/container_test.go
+++ b/container_test.go
@@ -2,7 +2,6 @@ package containerd
 
 import (
 	"bytes"
-	"fmt"
 	"io/ioutil"
 	"os"
 	"runtime"
diff --git a/metadata/snapshot_test.go b/metadata/snapshot_test.go
index 573d3b83d..37800dc40 100644
--- a/metadata/snapshot_test.go
+++ b/metadata/snapshot_test.go
@@ -13,7 +13,7 @@ import (
 	"github.com/containerd/containerd/testutil"
 )
 
-func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
+func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error) {
 	naiveRoot := filepath.Join(root, "naive")
 	if err := os.Mkdir(naiveRoot, 0770); err != nil {
 		return nil, nil, err
@@ -30,8 +30,8 @@ func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, fun
 
 	sn := NewSnapshotter(db, "naive", snapshotter)
 
-	return sn, func() {
-		db.Close()
+	return sn, func() error {
+		return db.Close()
 	}, nil
 }
 
diff --git a/snapshot/btrfs/btrfs_test.go b/snapshot/btrfs/btrfs_test.go
index 738da0048..83fd7d54d 100644
--- a/snapshot/btrfs/btrfs_test.go
+++ b/snapshot/btrfs/btrfs_test.go
@@ -16,9 +16,10 @@ import (
 	"github.com/containerd/containerd/snapshot/testsuite"
 	"github.com/containerd/containerd/testutil"
 	"github.com/pkg/errors"
+	"golang.org/x/sys/unix"
 )
 
-func boltSnapshotter(t *testing.T) func(context.Context, string) (snapshot.Snapshotter, func(), error) {
+func boltSnapshotter(t *testing.T) func(context.Context, string) (snapshot.Snapshotter, func() error, error) {
 	mkbtrfs, err := exec.LookPath("mkfs.btrfs")
 	if err != nil {
 		t.Skipf("could not find mkfs.btrfs: %v", err)
@@ -26,7 +27,7 @@ func boltSnapshotter(t *testing.T) func(context.Context, string) (snapshot.Snaps
 
 	// TODO: Check for btrfs in /proc/module and skip if not loaded
 
-	return func(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
+	return func(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error) {
 
 		deviceName, cleanupDevice, err := testutil.NewLoopback(100 << 20) // 100 MB
 		if err != nil {
@@ -45,11 +46,14 @@ func boltSnapshotter(t *testing.T) func(context.Context, string) (snapshot.Snaps
 			return nil, nil, errors.Wrap(err, "failed to create new snapshotter")
 		}
 
-		return snapshotter, func() {
-			testutil.Unmount(t, root)
-			if err := cleanupDevice(); err != nil {
-				t.Errorf("Device cleanup failed: %v", err)
+		return snapshotter, func() (err error) {
+			merr := mount.UnmountAll(root, unix.MNT_DETACH)
+			if err = cleanupDevice(); err != nil {
+				return errors.Wrap(err, "device cleanup failed")
+			} else {
+				err = merr
 			}
+			return err
 		}, nil
 	}
 }
diff --git a/snapshot/naive/naive_test.go b/snapshot/naive/naive_test.go
index 67ac2cc4f..279e95505 100644
--- a/snapshot/naive/naive_test.go
+++ b/snapshot/naive/naive_test.go
@@ -9,13 +9,13 @@ import (
 	"github.com/containerd/containerd/testutil"
 )
 
-func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
+func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error) {
 	snapshotter, err := NewSnapshotter(root)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	return snapshotter, func() {}, nil
+	return snapshotter, nil, nil
 }
 
 func TestNaive(t *testing.T) {
diff --git a/snapshot/overlay/overlay_test.go b/snapshot/overlay/overlay_test.go
index 5b47f07ae..870b31a3f 100644
--- a/snapshot/overlay/overlay_test.go
+++ b/snapshot/overlay/overlay_test.go
@@ -18,13 +18,13 @@ import (
 	"github.com/containerd/containerd/testutil"
 )
 
-func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
+func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error) {
 	snapshotter, err := NewSnapshotter(root)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	return snapshotter, func() {}, nil
+	return snapshotter, nil, nil
 }
 
 func TestOverlay(t *testing.T) {
diff --git a/snapshot/testsuite/helpers.go b/snapshot/testsuite/helpers.go
index a0be722d1..8d4acb904 100644
--- a/snapshot/testsuite/helpers.go
+++ b/snapshot/testsuite/helpers.go
@@ -21,11 +21,11 @@ func applyToMounts(m []mount.Mount, work string, a fstest.Applier) (err error) {
 	defer os.RemoveAll(td)
 
 	if err := mount.MountAll(m, td); err != nil {
-		return err
+		return errors.Wrap(err, "failed to mount")
 	}
 	defer func() {
-		if err1 := mount.UnmountAll(td, 0); err == nil {
-			err = err1
+		if err1 := mount.UnmountAll(td, umountflags); err == nil {
+			err = errors.Wrap(err1, "failed to unmount")
 		}
 	}()
 
@@ -40,26 +40,30 @@ func createSnapshot(ctx context.Context, sn snapshot.Snapshotter, parent, work s
 
 	m, err := sn.Prepare(ctx, prepare, parent)
 	if err != nil {
-		return "", err
+		return "", errors.Wrap(err, "failed to prepare snapshot")
 	}
 
 	if err := applyToMounts(m, work, a); err != nil {
-		return "", err
+		return "", errors.Wrap(err, "failed to apply")
 	}
 
 	if err := sn.Commit(ctx, n, prepare); err != nil {
-		return "", err
+		return "", errors.Wrap(err, "failed to commit")
 	}
 
 	return n, nil
 }
 
-func checkSnapshot(ctx context.Context, sn snapshot.Snapshotter, work, name, check string) error {
+func checkSnapshot(ctx context.Context, sn snapshot.Snapshotter, work, name, check string) (err error) {
 	td, err := ioutil.TempDir(work, "check")
 	if err != nil {
 		return errors.Wrap(err, "failed to create temp dir")
 	}
-	defer os.RemoveAll(td)
+	defer func() {
+		if err1 := os.RemoveAll(td); err == nil {
+			err = errors.Wrapf(err1, "failed to remove temporary directory %s", td)
+		}
+	}()
 
 	view := fmt.Sprintf("%s-view", name)
 	m, err := sn.View(ctx, view, name)
@@ -73,10 +77,10 @@ func checkSnapshot(ctx context.Context, sn snapshot.Snapshotter, work, name, che
 	}()
 
 	if err := mount.MountAll(m, td); err != nil {
-		return errors.Wrap(err, "failed to unmount")
+		return errors.Wrap(err, "failed to mount")
 	}
 	defer func() {
-		if err1 := mount.UnmountAll(td, 0); err == nil {
+		if err1 := mount.UnmountAll(td, umountflags); err == nil {
 			err = errors.Wrap(err1, "failed to unmount view")
 		}
 	}()
diff --git a/snapshot/testsuite/issues.go b/snapshot/testsuite/issues.go
index 84b7a5e01..a41c401f0 100644
--- a/snapshot/testsuite/issues.go
+++ b/snapshot/testsuite/issues.go
@@ -22,8 +22,6 @@ import (
 // avoid such issues by not relying on tar to create layers.
 // See https://github.com/docker/docker/issues/21555
 func checkLayerFileUpdate(ctx context.Context, t *testing.T, sn snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	l1Init := fstest.Apply(
 		fstest.CreateDir("/etc", 0700),
 		fstest.CreateFile("/etc/hosts", []byte("mydomain 10.0.0.1"), 0644),
@@ -55,8 +53,6 @@ func checkLayerFileUpdate(ctx context.Context, t *testing.T, sn snapshot.Snapsho
 // checkRemoveDirectoryInLowerLayer
 // See https://github.com/docker/docker/issues/25244
 func checkRemoveDirectoryInLowerLayer(ctx context.Context, t *testing.T, sn snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	l1Init := fstest.Apply(
 		fstest.CreateDir("/lib", 0700),
 		fstest.CreateFile("/lib/hidden", []byte{}, 0644),
@@ -80,8 +76,6 @@ func checkRemoveDirectoryInLowerLayer(ctx context.Context, t *testing.T, sn snap
 // See https://github.com/docker/docker/issues/24913 overlay
 // see https://github.com/docker/docker/issues/28391 overlay2
 func checkChown(ctx context.Context, t *testing.T, sn snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	l1Init := fstest.Apply(
 		fstest.CreateDir("/opt", 0700),
 		fstest.CreateDir("/opt/a", 0700),
@@ -124,8 +118,6 @@ func checkRename(ctx context.Context, t *testing.T, sn snapshot.Snapshotter, wor
 // checkDirectoryPermissionOnCommit
 // https://github.com/docker/docker/issues/27298
 func checkDirectoryPermissionOnCommit(ctx context.Context, t *testing.T, sn snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	l1Init := fstest.Apply(
 		fstest.CreateDir("/dir1", 0700),
 		fstest.CreateDir("/dir2", 0700),
diff --git a/snapshot/testsuite/testsuite.go b/snapshot/testsuite/testsuite.go
index 467b30104..df934c7f8 100644
--- a/snapshot/testsuite/testsuite.go
+++ b/snapshot/testsuite/testsuite.go
@@ -19,8 +19,9 @@ import (
 )
 
 // SnapshotterSuite runs a test suite on the snapshotter given a factory function.
-func SnapshotterSuite(t *testing.T, name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func(), error)) {
-	t.Parallel()
+func SnapshotterSuite(t *testing.T, name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error)) {
+	restoreMask := clearMask()
+	defer restoreMask()
 
 	t.Run("Basic", makeTest(name, snapshotterFn, checkSnapshotterBasic))
 	t.Run("StatActive", makeTest(name, snapshotterFn, checkSnapshotterStatActive))
@@ -39,12 +40,12 @@ func SnapshotterSuite(t *testing.T, name string, snapshotterFn func(ctx context.
 	//t.Run("Rename", makeTest(name, snapshotterFn, checkRename))
 }
 
-func makeTest(name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func(), error), fn func(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string)) func(t *testing.T) {
+func makeTest(name string, snapshotterFn func(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error), fn func(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string)) func(t *testing.T) {
 	return func(t *testing.T) {
+		t.Parallel()
+
 		ctx := context.Background()
 		ctx = namespaces.WithNamespace(ctx, "testsuite")
-		restoreMask := clearMask()
-		defer restoreMask()
 		// Make two directories: a snapshotter root and a play area for the tests:
 		//
 		// 	/tmp
@@ -64,9 +65,15 @@ func makeTest(name string, snapshotterFn func(ctx context.Context, root string)
 
 		snapshotter, cleanup, err := snapshotterFn(ctx, root)
 		if err != nil {
-			t.Fatal(err)
+			t.Fatalf("Failed to initialize snapshotter: %+v", err)
 		}
-		defer cleanup()
+		defer func() {
+			if cleanup != nil {
+				if err := cleanup(); err != nil {
+					t.Errorf("Cleanup failed: %v", err)
+				}
+			}
+		}()
 
 		work := filepath.Join(tmpDir, "work")
 		if err := os.MkdirAll(work, 0777); err != nil {
@@ -80,9 +87,6 @@ func makeTest(name string, snapshotterFn func(ctx context.Context, root string)
 
 // checkSnapshotterBasic tests the basic workflow of a snapshot snapshotter.
 func checkSnapshotterBasic(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	// TODO: this always fails when run in parallel, why?
-	//	t.Parallel()
-
 	initialApplier := fstest.Apply(
 		fstest.CreateFile("/foo", []byte("foo\n"), 0777),
 		fstest.CreateDir("/a", 0755),
@@ -216,8 +220,6 @@ func checkSnapshotterBasic(ctx context.Context, t *testing.T, snapshotter snapsh
 
 // Create a New Layer on top of base layer with Prepare, Stat on new layer, should return Active layer.
 func checkSnapshotterStatActive(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	preparing := filepath.Join(work, "preparing")
 	if err := os.MkdirAll(preparing, 0777); err != nil {
 		t.Fatal(err)
@@ -252,8 +254,6 @@ func checkSnapshotterStatActive(ctx context.Context, t *testing.T, snapshotter s
 
 // Commit a New Layer on top of base layer with Prepare & Commit , Stat on new layer, should return Committed layer.
 func checkSnapshotterStatCommitted(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	preparing := filepath.Join(work, "preparing")
 	if err := os.MkdirAll(preparing, 0777); err != nil {
 		t.Fatal(err)
@@ -315,8 +315,6 @@ func snapshotterPrepareMount(ctx context.Context, snapshotter snapshot.Snapshott
 
 // Given A <- B <- C, B is the parent of C and A is a transitive parent of C (in this case, a "grandparent")
 func checkSnapshotterTransitivity(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	preparing, err := snapshotterPrepareMount(ctx, snapshotter, "preparing", "", work)
 	if err != nil {
 		t.Fatal(err)
@@ -371,8 +369,6 @@ func checkSnapshotterTransitivity(ctx context.Context, t *testing.T, snapshotter
 
 // Creating two layers with Prepare or View with same key must fail.
 func checkSnapshotterPrepareView(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	preparing, err := snapshotterPrepareMount(ctx, snapshotter, "preparing", "", work)
 	if err != nil {
 		t.Fatal(err)
@@ -469,8 +465,6 @@ func baseTestSnapshots(ctx context.Context, snapshotter snapshot.Snapshotter) er
 }
 
 func checkUpdate(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	t1 := time.Now().UTC()
 	if err := baseTestSnapshots(ctx, snapshotter); err != nil {
 		t.Fatalf("Failed to create base snapshots: %v", err)
@@ -622,8 +616,6 @@ func assertLabels(t *testing.T, actual, expected map[string]string) {
 }
 
 func checkRemove(ctx context.Context, t *testing.T, snapshotter snapshot.Snapshotter, work string) {
-	t.Parallel()
-
 	if _, err := snapshotter.Prepare(ctx, "committed-a", ""); err != nil {
 		t.Fatal(err)
 	}
diff --git a/snapshot/testsuite/testsuite_unix.go b/snapshot/testsuite/testsuite_unix.go
index 6a02eda9d..14dc85864 100644
--- a/snapshot/testsuite/testsuite_unix.go
+++ b/snapshot/testsuite/testsuite_unix.go
@@ -2,7 +2,13 @@
 
 package testsuite
 
-import "syscall"
+import (
+	"syscall"
+
+	"golang.org/x/sys/unix"
+)
+
+const umountflags int = unix.MNT_DETACH
 
 func clearMask() func() {
 	oldumask := syscall.Umask(0)
diff --git a/snapshot/testsuite/testsuite_windows.go b/snapshot/testsuite/testsuite_windows.go
index c3cc8c22b..c48cca3e6 100644
--- a/snapshot/testsuite/testsuite_windows.go
+++ b/snapshot/testsuite/testsuite_windows.go
@@ -1,5 +1,7 @@
 package testsuite
 
+const umountflags int = 0
+
 func clearMask() func() {
 	return func() {}
 }
diff --git a/snapshot_test.go b/snapshot_test.go
index ccf28c70c..0bcab7876 100644
--- a/snapshot_test.go
+++ b/snapshot_test.go
@@ -9,7 +9,7 @@ import (
 	"github.com/containerd/containerd/snapshot/testsuite"
 )
 
-func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func(), error) {
+func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, func() error, error) {
 	client, err := New(address)
 	if err != nil {
 		return nil, nil, err
@@ -17,8 +17,8 @@ func newSnapshotter(ctx context.Context, root string) (snapshot.Snapshotter, fun
 
 	sn := client.SnapshotService(DefaultSnapshotter)
 
-	return sn, func() {
-		client.Close()
+	return sn, func() error {
+		return client.Close()
 	}, nil
 }
 
diff --git a/testutil/helpers_unix.go b/testutil/helpers_unix.go
index 398209df1..fd207449e 100644
--- a/testutil/helpers_unix.go
+++ b/testutil/helpers_unix.go
@@ -9,12 +9,13 @@ import (
 
 	"github.com/containerd/containerd/mount"
 	"github.com/stretchr/testify/assert"
+	"golang.org/x/sys/unix"
 )
 
 // Unmount unmounts a given mountPoint and sets t.Error if it fails
 func Unmount(t *testing.T, mountPoint string) {
 	t.Log("unmount", mountPoint)
-	if err := mount.Unmount(mountPoint, 0); err != nil {
+	if err := mount.UnmountAll(mountPoint, unix.MNT_DETACH); err != nil {
 		t.Error("Could not umount", mountPoint, err)
 	}
 }