diff --git a/packages/mbed-greentea/mbed_greentea/mbed_greentea_cli.py b/packages/mbed-greentea/mbed_greentea/mbed_greentea_cli.py
index 916ceb89b8..b2ad4d7523 100644
--- a/packages/mbed-greentea/mbed_greentea/mbed_greentea_cli.py
+++ b/packages/mbed-greentea/mbed_greentea/mbed_greentea_cli.py
@@ -569,7 +569,7 @@ def run_test_thread(test_result_queue, test_queue, opts, mut, build, build_path,
             # In some cases we want to print console to see why test failed
             # even if we are not in verbose mode
             gt_logger.gt_log_tab("test failed, reporting console output (specified with --report-fails option)")
-            print
+            print()
             print(single_test_output)
 
     #greentea_release_target_id(mut['target_id'], gt_instance_uuid)
diff --git a/src/mbed_os_tools/detect/lstools_base.py b/src/mbed_os_tools/detect/lstools_base.py
index c716063abc..e7852870ec 100644
--- a/src/mbed_os_tools/detect/lstools_base.py
+++ b/src/mbed_os_tools/detect/lstools_base.py
@@ -28,6 +28,7 @@
     LOCAL_PLATFORM_DATABASE,
     LOCAL_MOCKS_DATABASE,
 )
+from future.utils import with_metaclass
 
 mbedls_root_logger = logging.getLogger("mbedls")
 mbedls_root_logger.setLevel(logging.WARNING)
@@ -56,13 +57,11 @@ class FSInteraction(object):
     Never = 3
 
 
-class MbedLsToolsBase(object):
+class MbedLsToolsBase(with_metaclass(ABCMeta, object)):
     """ Base class for mbed-lstools, defines mbed-ls tools interface for
     mbed-enabled devices detection for various hosts
     """
 
-    __metaclass__ = ABCMeta
-
     # Which OSs are supported by this module
     # Note: more than one OS can be supported by mbed-lstools_* module
     os_supported = []
diff --git a/src/mbed_os_tools/test/mbed_greentea_hooks.py b/src/mbed_os_tools/test/mbed_greentea_hooks.py
index b07cf36d82..0d0fd695b8 100644
--- a/src/mbed_os_tools/test/mbed_greentea_hooks.py
+++ b/src/mbed_os_tools/test/mbed_greentea_hooks.py
@@ -24,7 +24,7 @@
 """
 
 
-class GreenteaTestHook():
+class GreenteaTestHook(object):
     """! Class used to define
     """
     name = None
@@ -204,7 +204,7 @@ def check_if_file_exists_or_is_empty(expr):
         result = result.replace('>>', '')
         return result
 
-class GreenteaHooks():
+class GreenteaHooks(object):
     """! Class used to store all hooks
     @details Hooks command starts with '$' dollar sign
     """
diff --git a/src/mbed_os_tools/test/mbed_greentea_log.py b/src/mbed_os_tools/test/mbed_greentea_log.py
index c758beb7b5..b82cfd2dba 100644
--- a/src/mbed_os_tools/test/mbed_greentea_log.py
+++ b/src/mbed_os_tools/test/mbed_greentea_log.py
@@ -22,7 +22,7 @@
     COLORAMA = False
 
 
-class GreenTeaSimpleLockLogger:
+class GreenTeaSimpleLockLogger(object):
     """! Simple locking printing mechanism
     @details We are using parallel testing
     """
diff --git a/src/mbed_os_tools/test/mbed_report_api.py b/src/mbed_os_tools/test/mbed_report_api.py
index e6f5af7d9d..4d303e074a 100644
--- a/src/mbed_os_tools/test/mbed_report_api.py
+++ b/src/mbed_os_tools/test/mbed_report_api.py
@@ -24,7 +24,7 @@ def export_to_file(file_name, payload):
         with open(file_name, 'w') as f:
             f.write(payload)
     except IOError as e:
-        print("Exporting report to file failed: ", str(e))
+        print("Exporting report to file failed: %s" % str(e))
         result = False
     return result
 
diff --git a/src/mbed_os_tools/test/mbed_yotta_module_parse.py b/src/mbed_os_tools/test/mbed_yotta_module_parse.py
index 6b1537ec6f..55a936ea22 100644
--- a/src/mbed_os_tools/test/mbed_yotta_module_parse.py
+++ b/src/mbed_os_tools/test/mbed_yotta_module_parse.py
@@ -17,7 +17,7 @@
 import json
 
 
-class YottaConfig():
+class YottaConfig(object):
 
     yotta_config = None
 
@@ -75,7 +75,7 @@ def get_test_pins(self):
         return None
 
 
-class YottaModule():
+class YottaModule(object):
 
     __yotta_module = None
     __greentea_client = 'greentea-client'
@@ -97,7 +97,7 @@ def init(self):
                 with open(path, 'r') as data_file:
                     self.__yotta_module = json.load(data_file)
         except IOError as e:
-            print("YottaModule: error - ", str(e))
+            print("YottaModule: error - %s" % str(e))
         return bool(self.__yotta_module)    # bool({}) == False
 
     def set_yotta_module(self, yotta_module):
diff --git a/src/mbed_os_tools/test/tests_spec.py b/src/mbed_os_tools/test/tests_spec.py
index 45f0522eb6..360fab025d 100644
--- a/src/mbed_os_tools/test/tests_spec.py
+++ b/src/mbed_os_tools/test/tests_spec.py
@@ -22,7 +22,7 @@
 import json
 
 
-class TestBinary:
+class TestBinary(object):
     """
     Class representing a Test Binary.
     """
@@ -66,7 +66,7 @@ def get_compare_log(self):
         return self.__comp_log
 
 
-class Test:
+class Test(object):
     """
     class representing a Test artifact that may contain more than one test binaries.
     """
@@ -136,7 +136,7 @@ def add_binary(self, path, binary_type, compare_log=None):
                                                                   compare_log)
 
 
-class TestBuild:
+class TestBuild(object):
     """
     class for Test build.
     """
@@ -245,7 +245,7 @@ def add_test(self, name, test):
         self.__tests[name] = test
 
 
-class TestSpec:
+class TestSpec(object):
     """
     Test specification. Contains Builds.
     """
@@ -275,7 +275,7 @@ def load(self, test_spec_filename):
             with open(test_spec_filename, "r") as f:
                 self.parse(json.load(f))
         except Exception as e:
-            print("TestSpec::load('%s')" % test_spec_filename, str(e))
+            print("TestSpec::load('%s') %s" % (test_spec_filename, str(e)))
             return False
 
         self.test_spec_filename = test_spec_filename