Minor bug fixes

- model::Db::lookupPaperNameFromId() bad if-else-if
- model::StrUtil::formatFraction missing arg in QString
- Added unit tests for StrUtil

model/unit_tests/TestStrUtil.h

@@ -0,0 +1,30 @@
+/*  TestColorNode.h
+ *
+ *  Copyright (C) 2019  Jaye Evins <evins@snaught.com>
+ *
+ *  This file is part of gLabels-qt.
+ *
+ *  gLabels-qt is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  gLabels-qt is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with gLabels-qt.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <QtTest/QtTest>
+
+
+class TestStrUtil : public QObject
+{
+	Q_OBJECT
+
+private slots:
+	void formatFraction();
+};