htlcswitch: clean up test resources and temporary files

The htlcswitch tests were creating temporary database files
but failing to clean them up.

We fix this by making it obvious when temporary db files are
created, and cleaning up those resources where necessary in
the tests.

htlcswitch/mock.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"path/filepath"
 	"sync"
 	"sync/atomic"
 	"testing"
@@ -161,30 +162,7 @@ type mockServer struct {
 
 var _ lnpeer.Peer = (*mockServer)(nil)
 
-func initDB() (*channeldb.DB, error) {
-	tempPath, err := ioutil.TempDir("", "switchdb")
-	if err != nil {
-		return nil, err
-	}
-
-	db, err := channeldb.Open(tempPath)
-	if err != nil {
-		return nil, err
-	}
-
-	return db, err
-}
-
 func initSwitchWithDB(startingHeight uint32, db *channeldb.DB) (*Switch, error) {
-	var err error
-
-	if db == nil {
-		db, err = initDB()
-		if err != nil {
-			return nil, err
-		}
-	}
-
 	signAliasUpdate := func(u *lnwire.ChannelUpdate) (*ecdsa.Signature,
 		error) {
 
@@ -226,6 +204,24 @@ func initSwitchWithDB(startingHeight uint32, db *channeldb.DB) (*Switch, error)
 	return New(cfg, startingHeight)
 }
 
+func initSwitchWithTempDB(t testing.TB, startingHeight uint32) (*Switch,
+	error) {
+
+	tempPath := filepath.Join(t.TempDir(), "switchdb")
+	db, err := channeldb.Open(tempPath)
+	if err != nil {
+		return nil, err
+	}
+	t.Cleanup(func() { db.Close() })
+
+	s, err := initSwitchWithDB(startingHeight, db)
+	if err != nil {
+		return nil, err
+	}
+
+	return s, nil
+}
+
 func newMockServer(t testing.TB, name string, startingHeight uint32,
 	db *channeldb.DB, defaultDelta uint32) (*mockServer, error) {
 
@@ -235,13 +231,25 @@ func newMockServer(t testing.TB, name string, startingHeight uint32,
 
 	pCache := newMockPreimageCache()
 
-	htlcSwitch, err := initSwitchWithDB(startingHeight, db)
+	var (
+		htlcSwitch *Switch
+		err        error
+	)
+	if db == nil {
+		htlcSwitch, err = initSwitchWithTempDB(t, startingHeight)
+	} else {
+		htlcSwitch, err = initSwitchWithDB(startingHeight, db)
+	}
 	if err != nil {
 		return nil, err
 	}
 
+	t.Cleanup(func() { _ = htlcSwitch.Stop() })
+
 	registry := newMockRegistry(defaultDelta)
 
+	t.Cleanup(func() { registry.cleanup() })
+
 	return &mockServer{
 		t:                t,
 		id:               id,