Update and reorganise themes (#893)

* Drop the subfolders for GUI themes
* Remove bundled font support
* Add safe file read function
* Allow loading themes from multiple locations
* Clean up unused variables
* Clean up icons class
* Merge icon theme icons
* Update icon theme class
* Remove guiDark config setting
* Fix tests
* Fix handling of default theme
* Update icon readmes
* Add test for getGuiItem common function

tests/test_base/test_base_common.py

@@ -29,12 +29,13 @@ from datetime import datetime
 from mock import causeOSError
 from tools import writeFile
 
+from novelwriter.guimain import GuiMain
 from novelwriter.common import (
     checkString, checkInt, checkBool, checkHandle, isHandle, isTitleTag,
     isItemClass, isItemType, isItemLayout, hexToInt, formatInt,
     formatTimeStamp, formatTime, parseTimeStamp, splitVersionNumber,
-    transferCase, fuzzyTime, numberToRoman, jsonEncode, makeFileNameSafe,
-    sha256sum, NWConfigParser
+    transferCase, fuzzyTime, numberToRoman, jsonEncode, readTextFile,
+    makeFileNameSafe, sha256sum, getGuiItem, NWConfigParser
 )
 
 
@@ -456,6 +457,24 @@ def testBaseCommon_JsonEncode():
 # END Test testBaseCommon_JsonEncode
 
 
+@pytest.mark.base
+def testBaseCommon_ReadTextFile(monkeypatch, fncDir, ipsumText):
+    """Test the readTextFile function.
+    """
+    testText = "\n\n".join(ipsumText) + "\n"
+    testFile = os.path.join(fncDir, "ipsum.txt")
+    writeFile(testFile, testText)
+
+    assert readTextFile(os.path.join(fncDir, "not_a_file.txt")) == ""
+    assert readTextFile(testFile) == testText
+
+    with monkeypatch.context() as mp:
+        mp.setattr("builtins.open", causeOSError)
+        assert readTextFile(testFile) == ""
+
+# END Test testBaseCommon_ReadTextFile
+
+
 @pytest.mark.base
 def testBaseCommon_MakeFileNameSafe():
     """Test the makeFileNameSafe function.
@@ -508,6 +527,16 @@ def testBaseCommon_Sha256Sum(monkeypatch, fncDir, ipsumText):
 # END Test testBaseCommon_Sha256Sum
 
 
+@pytest.mark.base
+def testBaseCommon_GetGuiItem(nwGUI):
+    """Check the GUI item function.
+    """
+    assert getGuiItem("gibberish") is None
+    assert isinstance(getGuiItem("GuiMain"), GuiMain)
+
+# END Test testBaseCommon_GetGuiItem
+
+
 @pytest.mark.base
 def testBaseCommon_NWConfigParser(fncDir):
     """Test the NWConfigParser subclass.