diff --git a/tests/test_base/test_base_common.py b/tests/test_base/test_base_common.py
index 8ac8f357..08e8b3e9 100644
--- a/tests/test_base/test_base_common.py
+++ b/tests/test_base/test_base_common.py
@@ -20,6 +20,8 @@ along with this program. If not, see <https://www.gnu.org/licenses/>.
 """
 
 import time
+from PyQt5.QtCore import QUrl
+from PyQt5.QtGui import QDesktopServices
 import pytest
 
 from pathlib import Path
@@ -32,10 +34,10 @@ from novelwriter.guimain import GuiMain
 from novelwriter.common import (
     checkBool, checkFloat, checkHandle, checkInt, checkIntTuple, checkPath,
     checkString, checkStringNone, checkUuid, formatInt, formatTime,
-    formatTimeStamp, fuzzyTime, getGuiItem, hexToInt, isHandle, isItemClass,
-    isItemLayout, isItemType, isTitleTag, jsonEncode, makeFileNameSafe, minmax,
-    numberToRoman, NWConfigParser, readTextFile, simplified, transferCase,
-    xmlIndent, yesNo
+    formatTimeStamp, fuzzyTime, getFileSize, getGuiItem, hexToInt, isHandle,
+    isItemClass, isItemLayout, isItemType, isTitleTag, jsonEncode,
+    makeFileNameSafe, minmax, numberToRoman, NWConfigParser, openExternalPath,
+    readTextFile, simplified, transferCase, xmlIndent, yesNo
 )
 
 
@@ -621,6 +623,37 @@ def testBaseCommon_makeFileNameSafe():
 # END Test testBaseCommon_makeFileNameSafe
 
 
+@pytest.mark.base
+def testBaseCommon_getFileSize(fncPath):
+    """Test the getFileSize function."""
+    (fncPath / "one.txt").write_bytes(b"foobar")
+    (fncPath / "two.txt").touch()
+
+    assert getFileSize(fncPath / "nope.txt") == -1
+    assert getFileSize(fncPath / "one.txt") == 6
+    assert getFileSize(fncPath / "two.txt") == 0
+
+# END Test testBaseCommon_getFileSize
+
+
+@pytest.mark.base
+def testBaseCommon_openExternalPath(monkeypatch, tstPaths):
+    """Test the openExternalPath function."""
+    lastUrl = ""
+
+    def mockOpenUrl(url: QUrl) -> None:
+        nonlocal lastUrl
+        lastUrl = url.toString()
+        return
+
+    monkeypatch.setattr(QDesktopServices, "openUrl", mockOpenUrl)
+    assert openExternalPath(Path("/foo/bar")) is False
+    assert openExternalPath(tstPaths.tmpDir) is True
+    assert lastUrl.startswith("file://")
+
+# END Test testBaseCommon_openExternalPath
+
+
 @pytest.mark.base
 def testBaseCommon_getGuiItem(nwGUI):
     """Check the GUI item function."""
diff --git a/tests/test_tools/test_tools_manusbuild.py b/tests/test_tools/test_tools_manusbuild.py
index 271f9b0f..a23f383e 100644
--- a/tests/test_tools/test_tools_manusbuild.py
+++ b/tests/test_tools/test_tools_manusbuild.py
@@ -19,6 +19,8 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <https://www.gnu.org/licenses/>.
 """
 
+from PyQt5.QtCore import QUrl
+from PyQt5.QtGui import QDesktopServices
 import pytest
 
 from pathlib import Path
@@ -132,6 +134,19 @@ def testManuscriptBuild_Main(
         mp.setattr(QMessageBox, "result", lambda *a: QMessageBox.No)
         assert manus._runBuild() is False
 
+    # Test that the open button works
+    lastUrl = ""
+
+    def mockOpenUrl(url: QUrl) -> None:
+        nonlocal lastUrl
+        lastUrl = url.toString()
+        return
+
+    with monkeypatch.context() as mp:
+        mp.setattr(QDesktopServices, "openUrl", mockOpenUrl)
+        manus.btnOpen.click()
+        assert lastUrl.startswith("file://")
+
     # Finish
     manus._dialogButtonClicked(manus.dlgButtons.button(QDialogButtonBox.Close))
     # qtbot.stop()