Fix Close() to also wait for view transactions and fix tests as well (#91)

* Fix testDB_Close_PendingTx to do something with the writable arg and stop it from closing twice

* Fix Close() to wait for view transactions by getting a full lock on mmaplock

* Fix the TestTx_Check_ReadOnly to close the view transaction

* Fix the TestTx_Commit_ErrTxNotWritable to close the view transaction

db.go

@@ -454,8 +454,8 @@ func (db *DB) Close() error {
 	db.metalock.Lock()
 	defer db.metalock.Unlock()
 
-	db.mmaplock.RLock()
-	defer db.mmaplock.RUnlock()
+	db.mmaplock.Lock()
+	defer db.mmaplock.Unlock()
 
 	return db.close()
 }

db_test.go

@@ -662,10 +662,9 @@ func TestDB_Close_PendingTx_RO(t *testing.T) { testDB_Close_PendingTx(t, false)
 // Ensure that a database cannot close while transactions are open.
 func testDB_Close_PendingTx(t *testing.T, writable bool) {
 	db := MustOpenDB()
-	defer db.MustClose()
 
 	// Start transaction.
-	tx, err := db.Begin(true)
+	tx, err := db.Begin(writable)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -687,8 +686,13 @@ func testDB_Close_PendingTx(t *testing.T, writable bool) {
 	default:
 	}
 
-	// Commit transaction.
-	if err := tx.Commit(); err != nil {
+	// Commit/close transaction.
+	if writable {
+		err = tx.Commit()
+	} else {
+		err = tx.Rollback()
+	}
+	if err != nil {
 		t.Fatal(err)
 	}
 

tx_test.go

@@ -57,6 +57,8 @@ func TestTx_Check_ReadOnly(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
+	// Close the view transaction
+	tx.Rollback()
 }
 
 // Ensure that committing a closed transaction returns an error.
@@ -110,6 +112,8 @@ func TestTx_Commit_ErrTxNotWritable(t *testing.T) {
 	if err := tx.Commit(); err != bolt.ErrTxNotWritable {
 		t.Fatal(err)
 	}
+	// Close the view transaction
+	tx.Rollback()
 }
 
 // Ensure that a transaction can retrieve a cursor on the root bucket.