Modify the tests to use memory database backend.

This commit modifies the tests to setup a chain instance backed by the new
memory database backend for btcdb.  This allows the tests to avoid
creating and cleaning up files and also allows the tests to run faster
since it can all happen in memory.

The chainSetup function has also been changed to provide logic to switch
on the database type to allow for easy changing of the backend to a
different database type as needed.  For example, it could be useful to
provide extra testing against new database backends.

common_test.go

@@ -9,12 +9,16 @@ import (
 	"github.com/conformal/btcchain"
 	"github.com/conformal/btcdb"
 	_ "github.com/conformal/btcdb/ldb"
+	_ "github.com/conformal/btcdb/memdb"
 	"github.com/conformal/btcutil"
 	"github.com/conformal/btcwire"
 	"os"
 	"path/filepath"
 )
 
+// testDbType is the database backend type to use for the tests.
+const testDbType = "memdb"
+
 // testDbRoot is the root directory used to create all test databases.
 const testDbRoot = "testdbs"
 
@@ -28,41 +32,78 @@ func fileExists(name string) bool {
 	return true
 }
 
+// isSupportedDbType returns whether or not the passed database type is
+// currently supported.
+func isSupportedDbType(dbType string) bool {
+	supportedDBs := btcdb.SupportedDBs()
+	for _, sDbType := range supportedDBs {
+		if dbType == sDbType {
+			return true
+		}
+	}
+
+	return false
+}
+
 // chainSetup is used to create a new db and chain instance with the genesis
 // block already inserted.  In addition to the new chain instnce, it returns
 // a teardown function the caller should invoke when done testing to clean up.
 func chainSetup(dbName string) (*btcchain.BlockChain, func(), error) {
-	// Create the root directory for test databases.
-	if !fileExists(testDbRoot) {
-		if err := os.MkdirAll(testDbRoot, 0700); err != nil {
-			err := fmt.Errorf("unable to create test db root: %v", err)
-			return nil, nil, err
+	if !isSupportedDbType(testDbType) {
+		return nil, nil, fmt.Errorf("unsupported db type %v", testDbType)
+	}
+
+	// Handle memory database specially since it doesn't need the disk
+	// specific handling.
+	var db btcdb.Db
+	var teardown func()
+	if testDbType == "memdb" {
+		ndb, err := btcdb.CreateDB(testDbType, "")
+		if err != nil {
+			return nil, nil, fmt.Errorf("error creating db: %v", err)
 		}
-	}
+		db = ndb
 
-	// Create a new database to store the accepted blocks into.
-	dbPath := filepath.Join(testDbRoot, dbName)
-	_ = os.RemoveAll(dbPath)
-	db, err := btcdb.CreateDB("leveldb", dbPath)
-	if err != nil {
-		return nil, nil, fmt.Errorf("error creating db: %v", err)
-	}
+		// Setup a teardown function for cleaning up.  This function is
+		// returned to the caller to be invoked when it is done testing.
+		teardown = func() {
+			db.Close()
+		}
+	} else {
+		// Create the root directory for test databases.
+		if !fileExists(testDbRoot) {
+			if err := os.MkdirAll(testDbRoot, 0700); err != nil {
+				err := fmt.Errorf("unable to create test db "+
+					"root: %v", err)
+				return nil, nil, err
+			}
+		}
 
-	// Setup a teardown function for cleaning up.  This function is returned
-	// to the caller to be invoked when it is done testing.
-	teardown := func() {
-		dbVersionPath := filepath.Join(testDbRoot, dbName+".ver")
-		db.Sync()
-		db.Close()
-		os.RemoveAll(dbPath)
-		os.Remove(dbVersionPath)
-		os.RemoveAll(testDbRoot)
+		// Create a new database to store the accepted blocks into.
+		dbPath := filepath.Join(testDbRoot, dbName)
+		_ = os.RemoveAll(dbPath)
+		ndb, err := btcdb.CreateDB(testDbType, dbPath)
+		if err != nil {
+			return nil, nil, fmt.Errorf("error creating db: %v", err)
+		}
+		db = ndb
+
+		// Setup a teardown function for cleaning up.  This function is
+		// returned to the caller to be invoked when it is done testing.
+		teardown = func() {
+			dbVersionPath := filepath.Join(testDbRoot, dbName+".ver")
+			db.Sync()
+			db.Close()
+			os.RemoveAll(dbPath)
+			os.Remove(dbVersionPath)
+			os.RemoveAll(testDbRoot)
+		}
 	}
 
 	// Insert the main network genesis block.  This is part of the initial
 	// database setup.
 	genesisBlock := btcutil.NewBlock(&btcwire.GenesisBlock)
-	_, err = db.InsertBlock(genesisBlock)
+	_, err := db.InsertBlock(genesisBlock)
 	if err != nil {
 		teardown()
 		err := fmt.Errorf("failed to insert genesis block: %v", err)