diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -32,6 +32,7 @@
 include(ECMSetupVersion)
 include(FeatureSummary)
 include(ECMQtDeclareLoggingCategory)
+include(ECMAddTests)
 
 find_package(
     Qt5 ${QT_MIN_VERSION} CONFIG REQUIRED
@@ -41,6 +42,7 @@
         DBus
         PrintSupport
         Quick
+        Test
 )
 
 find_package(
@@ -106,6 +108,7 @@
 add_subdirectory(desktop)
 add_subdirectory(icons)
 add_subdirectory(doc)
+add_subdirectory(tests)
 
 install( FILES spectacle.categories DESTINATION ${KDE_INSTALL_CONFDIR} )
 # summaries
diff --git a/src/ExportManager.h b/src/ExportManager.h
--- a/src/ExportManager.h
+++ b/src/ExportManager.h
@@ -63,6 +63,7 @@
     void setPixmap(const QPixmap &pixmap);
     QPixmap pixmap() const;
     void updatePixmapTimestamp();
+    void setTimestamp(const QDateTime &timestamp);
     void setWindowTitle(const QString &windowTitle);
     QString windowTitle() const;
     ImageGrabber::GrabMode grabMode() const;
diff --git a/src/ExportManager.cpp b/src/ExportManager.cpp
--- a/src/ExportManager.cpp
+++ b/src/ExportManager.cpp
@@ -109,6 +109,11 @@
 	mPixmapTimestamp = QDateTime::currentDateTime();
 }
 
+void ExportManager::setTimestamp(const QDateTime &timestamp)
+{
+    mPixmapTimestamp = timestamp;
+}
+
 // native file save helpers
 
 QString ExportManager::defaultSaveLocation() const
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/tests/CMakeLists.txt
@@ -0,0 +1,9 @@
+include_directories(${CMAKE_CURRENT_SOURCE_DIR}/../src)
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+
+ecm_add_test(FilenameTest.cpp
+        ../src/ExportManager.cpp ../src/SpectacleConfig.cpp ../src/PlatformBackends/ImageGrabber.cpp
+    TEST_NAME "filename_test"
+    LINK_LIBRARIES  Qt5::Test 
+        Qt5::PrintSupport KF5::I18n KF5::ConfigCore KF5::KIOCore KF5::WindowSystem
+)
diff --git a/tests/FilenameTest.cpp b/tests/FilenameTest.cpp
new file mode 100644
--- /dev/null
+++ b/tests/FilenameTest.cpp
@@ -0,0 +1,91 @@
+#include <QDir>
+#include <QFile>
+#include <QtTest>
+#include <QUuid>
+
+#include "ExportManager.h"
+
+class FilenameTest : public QObject
+{
+    Q_OBJECT
+private:
+    ExportManager* em;
+private Q_SLOTS:
+    void initTestCase();
+    void testStrings();
+    void testDateTokens();
+    void testWindowTitle();
+    void testNumbering();
+    void testCombined();
+};
+
+void FilenameTest::initTestCase()
+{
+    em = ExportManager::instance();
+    em->setTimestamp(QDateTime::fromString(QStringLiteral("2019-03-22T10:43:25"), Qt::ISODate));
+    em->setWindowTitle(QStringLiteral("Spectacle"));
+}
+
+void FilenameTest::testStrings()
+{
+    QCOMPARE(em->formatFilename(QStringLiteral("Screenshot")), QStringLiteral("Screenshot"));
+    // empty string produces Screenshot per default
+    QCOMPARE(em->formatFilename(QStringLiteral("")), QStringLiteral("Screenshot"));
+    // not a placeholder
+    QCOMPARE(em->formatFilename(QStringLiteral("%")), QStringLiteral("%"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%K")), QStringLiteral("%K"));
+}
+
+void FilenameTest::testDateTokens()
+{
+    QCOMPARE(em->formatFilename(QStringLiteral("%Y")), QStringLiteral("2019"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%y")), QStringLiteral("19"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%M")), QStringLiteral("03"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%D")), QStringLiteral("22"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%H")), QStringLiteral("10"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%m")), QStringLiteral("43"));
+    QCOMPARE(em->formatFilename(QStringLiteral("%S")), QStringLiteral("25"));
+}
+
+void FilenameTest::testWindowTitle()
+{
+    em->setGrabMode(ImageGrabber::ActiveWindow);
+    QCOMPARE(em->formatFilename(QStringLiteral("%T")), QStringLiteral("Spectacle"));
+    QCOMPARE(em->formatFilename(QStringLiteral("Before%TAfter")),
+             QStringLiteral("BeforeSpectacleAfter"));
+    em->setGrabMode(ImageGrabber::FullScreen);
+    //Empty String produces Screenshot
+    QCOMPARE(em->formatFilename(QStringLiteral("%T")), QStringLiteral("Screenshot"));
+    QCOMPARE(em->formatFilename(QStringLiteral("Before%TAfter")), QStringLiteral("BeforeAfter"));
+    QCOMPARE(em->formatFilename(QStringLiteral("Before_%T_After")), QStringLiteral("Before_After"));
+}
+
+void FilenameTest::testNumbering()
+{
+    QString baseName = QStringLiteral("spectacle_test_")+ QUuid::createUuid().toString();
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%d")), baseName+QStringLiteral("_1"));
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%1d")), baseName+QStringLiteral("_1"));
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%2d")), baseName+QStringLiteral("_01"));
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%3d")), baseName+QStringLiteral("_001"));
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%4d")), baseName+QStringLiteral("_0001"));
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%d_%2d_%3d")),
+             baseName+QStringLiteral("_1_01_001"));
+    QFile file(QDir(em->defaultSaveLocation()).filePath(baseName + QStringLiteral("_1.png")));
+    file.open(QIODevice::WriteOnly);
+    QCOMPARE(em->formatFilename(baseName+QStringLiteral("_%d")), baseName+QStringLiteral("_2"));
+    file.remove();
+}
+
+void FilenameTest::testCombined()
+{
+    em->setGrabMode(ImageGrabber::ActiveWindow);
+    QCOMPARE(em->formatFilename(QStringLiteral("App_%T_Date_%Y%M%D_Time_%H:%m:%S%F")),
+             QStringLiteral("App_Spectacle_Date_20190322_Time_10:43:25%F"));
+    em->setGrabMode(ImageGrabber::FullScreen);
+    QCOMPARE(em->formatFilename(QStringLiteral("App_%T_Date_%Y%M%D_Time_%H:%m:%S%F")),
+             QStringLiteral("App_Date_20190322_Time_10:43:25%F"));
+}
+
+QTEST_MAIN(FilenameTest)
+
+#include "FilenameTest.moc"