diff --git a/tests/system/shared/editor_utils.py b/tests/system/shared/editor_utils.py
index 9af13028486..bb6e8ba299d 100644
--- a/tests/system/shared/editor_utils.py
+++ b/tests/system/shared/editor_utils.py
@@ -37,7 +37,7 @@ def placeCursorToLine(editor, line, isRegex=False):
         return waitForObject(editor)
 
     isDarwin = platform.system() == 'Darwin'
-    if not isinstance(editor, (str, unicode)):
+    if not isString(editor):
         editor = objectMap.realName(editor)
     oldPosition = 0
     jumpToFirstLine(getEditor())
@@ -120,7 +120,7 @@ def replaceEditorContent(editor, newcontent):
     type(editor, newcontent)
 
 def typeLines(editor, lines):
-    if isinstance(lines, (str, unicode)):
+    if isString(lines):
         lines = [lines]
     if isinstance(lines, (list, tuple)):
         for line in lines:
diff --git a/tests/system/shared/fs_utils.py b/tests/system/shared/fs_utils.py
index f36fbd7fbf2..ee24d6f0ca3 100644
--- a/tests/system/shared/fs_utils.py
+++ b/tests/system/shared/fs_utils.py
@@ -35,10 +35,10 @@ def changeFilePermissions(dirPath, readPerm, writePerm, excludeFileNames=None):
         permission |= stat.S_IWRITE
     if excludeFileNames == None:
         excludeFileNames = []
-    elif isinstance(excludeFileNames, (str, unicode)):
+    elif isString(excludeFileNames):
         excludeFileNames = [excludeFileNames]
     if not isinstance(excludeFileNames, (tuple, list)):
-        test.warning("File names to exclude must be of type str, unicode, list, tuple or None - "
+        test.warning("File names to exclude must be of type str, list, tuple or None - "
                      "ignoring parameter this time.")
         excludeFileNames = []
     if not os.path.isdir(dirPath):
diff --git a/tests/system/shared/project_explorer.py b/tests/system/shared/project_explorer.py
index 587574ff0a5..a4abeb7a723 100644
--- a/tests/system/shared/project_explorer.py
+++ b/tests/system/shared/project_explorer.py
@@ -95,8 +95,8 @@ def setRunInTerminal(wantedKit, runInTerminal=True):
     switchViewTo(ViewConstants.EDIT)
 
 def __getTargetFromToolTip__(toolTip):
-    if toolTip == None or not isinstance(toolTip, (str, unicode)):
-        test.warning("Parameter toolTip must be of type str or unicode and can't be None!")
+    if toolTip == None or not isString(toolTip):
+        test.warning("Parameter toolTip must be of type str and can't be None!")
         return None
     pattern = re.compile(".*<b>Kit:</b>(.*)<b>Deploy.*")
     target = pattern.match(toolTip)
@@ -108,7 +108,7 @@ def __getTargetFromToolTip__(toolTip):
 
 def getExecutableAndTargetFromToolTip(toolTip):
     target = __getTargetFromToolTip__(toolTip)
-    if toolTip == None or not isinstance(toolTip, (str, unicode)):
+    if toolTip == None or not isString(toolTip):
         return None, target
     pattern = re.compile('.*<b>Run:</b>(.*)</.*')
     exe = pattern.match(toolTip)
diff --git a/tests/system/shared/utils.py b/tests/system/shared/utils.py
index 74ce0723924..c67cbc57517 100644
--- a/tests/system/shared/utils.py
+++ b/tests/system/shared/utils.py
@@ -76,7 +76,7 @@ def ensureChecked(objectName, shouldBeChecked = True, timeout=20000):
 #                   or the object itself. If it is an object, it must exist already.
 # param expectedState is the expected enable state of the object
 def verifyEnabled(objectSpec, expectedState = True):
-    if isinstance(objectSpec, (str, unicode)):
+    if isString(objectSpec):
         waitFor("object.exists('" + str(objectSpec).replace("'", "\\'") + "')", 20000)
         foundObject = findObject(objectSpec)
     else:
@@ -154,7 +154,7 @@ def which(program):
 def cleanUpUserFiles(pathsToProFiles=None):
     if pathsToProFiles==None:
         return False
-    if isinstance(pathsToProFiles, (str, unicode)):
+    if isString(pathsToProFiles):
         filelist = glob.glob(pathsToProFiles+".user*")
     elif isinstance(pathsToProFiles, (list, tuple)):
         filelist = []
@@ -398,10 +398,10 @@ def enabledCheckBoxExists(text):
 
 # this function verifies if the text matches the given
 # regex inside expectedTexts
-# param text must be a single str/unicode
-# param expectedTexts can be str/unicode/list/tuple
+# param text must be a single str
+# param expectedTexts can be str/list/tuple
 def regexVerify(text, expectedTexts):
-    if isinstance(expectedTexts, (str,unicode)):
+    if isString(expectedTexts):
         expectedTexts = [expectedTexts]
     for curr in expectedTexts:
         pattern = re.compile(curr)
@@ -453,7 +453,7 @@ def iterateQtVersions(keepOptionsOpen=False, alreadyOnOptionsDialog=False,
                 result.append({target:version})
                 if additionalFunction:
                     try:
-                        if isinstance(additionalFunction, (str, unicode)):
+                        if isString(additionalFunction):
                             currResult = globals()[additionalFunction](target, version, *argsForAdditionalFunc)
                         else:
                             currResult = additionalFunction(target, version, *argsForAdditionalFunc)
@@ -514,7 +514,7 @@ def iterateKits(keepOptionsOpen=False, alreadyOnOptionsDialog=False,
                              currentItem.replace(".", "\\.")])
             if additionalFunction:
                 try:
-                    if isinstance(additionalFunction, (str, unicode)):
+                    if isString(additionalFunction):
                         currResult = globals()[additionalFunction](item, kitName, *argsForAdditionalFunc)
                     else:
                         currResult = additionalFunction(item, kitName, *argsForAdditionalFunc)
@@ -674,3 +674,10 @@ def getHelpViewer():
 
 def getHelpTitle():
     return str(getHelpViewer().title())
+
+
+def isString(sth):
+    if sys.version_info.major > 2:
+        return isinstance(sth, str)
+    else:
+        return isinstance(sth, (str, unicode))
diff --git a/tests/system/suite_general/tst_default_settings/test.py b/tests/system/suite_general/tst_default_settings/test.py
index 2cb40725b82..29c65425b09 100644
--- a/tests/system/suite_general/tst_default_settings/test.py
+++ b/tests/system/suite_general/tst_default_settings/test.py
@@ -306,7 +306,7 @@ def __compareCompilers__(foundCompilers, expectedCompilers):
         if isinstance(currentFound, dict):
             foundExp = False
             for currentExp in expectedCompilers:
-                if isinstance(currentExp, (str, unicode)):
+                if isString(currentExp):
                     continue
                 key = currentExp.keys()[0]
                 # special case for (fuzzy) regex comparison on Windows (internal LLVM)
@@ -353,7 +353,7 @@ def __compareDebuggers__(foundDebuggers, expectedDebuggers):
 
 def __lowerStrs__(iterable):
     for it in iterable:
-        if isinstance(it, (str, unicode)):
+        if isString(it):
             yield it.lower()
         else:
             yield it