diff --git a/python/helpers/pycharm/teamcity/messages.py b/python/helpers/pycharm/teamcity/messages.py
index 7ddb4078aff1..3e528407cadb 100644
--- a/python/helpers/pycharm/teamcity/messages.py
+++ b/python/helpers/pycharm/teamcity/messages.py
@@ -1,6 +1,6 @@
 # coding=utf-8
 import sys
-import datetime
+import time
 
 if sys.version_info < (3, ):
     # Python 2
@@ -10,6 +10,11 @@ else:
     text_type = str
 
 
+# Capture some time functions to allow monkeypatching them in tests
+_time = time.time
+_localtime = time.localtime
+_strftime = time.strftime
+
 _quote = {"'": "|'", "|": "||", "\n": "|n", "\r": "|r", '[': '|[', ']': '|]'}
 
 def escape_value(value):
@@ -17,7 +22,7 @@ def escape_value(value):
 
 
 class TeamcityServiceMessages(object):
-    def __init__(self, output=sys.stdout, now=datetime.datetime.now, encoding='auto'):
+    def __init__(self, output=sys.stdout, now=_time, encoding='auto'):
         if sys.version_info < (3, ) or not hasattr(output, 'buffer'):
             self.output = output
         else:
@@ -52,7 +57,11 @@ class TeamcityServiceMessages(object):
             return escape_value(self.decode(value))
 
     def message(self, messageName, **properties):
-        timestamp = self.now().strftime("%Y-%m-%dT%H:%M:%S.") + "%03d" % (self.now().microsecond / 1000)
+        current_time = self.now()
+        (current_time_int, current_time_fraction) = divmod(current_time, 1)
+        current_time_struct = _localtime(current_time_int)
+
+        timestamp = _strftime("%Y-%m-%dT%H:%M:%S.", current_time_struct) + "%03d" % (int(current_time_fraction * 1000))
         message = ("##teamcity[%s timestamp='%s'" % (messageName, timestamp))
 
         for k in sorted(properties.keys()):
diff --git a/python/testData/testRunner/env/pytest/monkeyPatch/test_test.py b/python/testData/testRunner/env/pytest/monkeyPatch/test_test.py
new file mode 100644
index 000000000000..d35060ba58d7
--- /dev/null
+++ b/python/testData/testRunner/env/pytest/monkeyPatch/test_test.py
@@ -0,0 +1,15 @@
+
+import time
+
+import pytest
+
+
+@pytest.fixture()
+def patch_time_strftime(monkeypatch):
+    def mockreturn(*args):
+        return '2016-7-25_8-54-30'
+    monkeypatch.setattr(time, 'strftime', mockreturn)
+
+
+def test_monkeypatch(patch_time_strftime):
+    assert time.strftime('%Y-%m-%d_%H-%M-%S') == '2016-7-25_8-54-30'
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/env/python/testing/PythonPyTestingTest.java b/python/testSrc/com/jetbrains/env/python/testing/PythonPyTestingTest.java
index f9180d4592c7..8551ef5a4f10 100644
--- a/python/testSrc/com/jetbrains/env/python/testing/PythonPyTestingTest.java
+++ b/python/testSrc/com/jetbrains/env/python/testing/PythonPyTestingTest.java
@@ -12,7 +12,6 @@ import com.intellij.util.PathUtil;
 import com.jetbrains.env.EnvTestTagsRequired;
 import com.jetbrains.env.PyEnvTestCase;
 import com.jetbrains.env.PyProcessWithConsoleTestTask;
-import com.jetbrains.env.ut.PyNoseTestProcessRunner;
 import com.jetbrains.env.ut.PyTestTestProcessRunner;
 import com.jetbrains.python.psi.PyFunction;
 import com.jetbrains.python.sdkTools.SdkCreationType;
@@ -42,7 +41,7 @@ public final class PythonPyTestingTest extends PyEnvTestCase {
   // Ensures setup/teardown does not break anything
   @Test
   public void testSetupTearDown() throws Exception {
-    runPythonTest(new SetupTearDownTestTask<PyTestTestProcessRunner>(){
+    runPythonTest(new SetupTearDownTestTask<PyTestTestProcessRunner>() {
       @NotNull
       @Override
       protected PyTestTestProcessRunner createProcessRunner() throws Exception {
@@ -56,7 +55,7 @@ public final class PythonPyTestingTest extends PyEnvTestCase {
    */
   @Test
   public void testRunModuleAsFile() throws Exception {
-    runPythonTest(new RunModuleAsFileTask<PyTestTestProcessRunner>(){
+    runPythonTest(new RunModuleAsFileTask<PyTestTestProcessRunner>() {
       @NotNull
       @Override
       protected PyTestTestProcessRunner createProcessRunner() throws Exception {
@@ -77,6 +76,29 @@ public final class PythonPyTestingTest extends PyEnvTestCase {
     });
   }
 
+
+  // Ensure test survives patched strftime
+  @Test
+  public void testMonkeyPatch() throws Exception {
+    runPythonTest(
+      new PyProcessWithConsoleTestTask<PyTestTestProcessRunner>("/testRunner/env/pytest/monkeyPatch", SdkCreationType.EMPTY_SDK) {
+
+        @NotNull
+        @Override
+        protected PyTestTestProcessRunner createProcessRunner() throws Exception {
+          return new PyTestTestProcessRunner("test_test.py", 0);
+        }
+
+        @Override
+        protected void checkTestResults(@NotNull PyTestTestProcessRunner runner,
+                                        @NotNull String stdout,
+                                        @NotNull String stderr,
+                                        @NotNull String all) {
+          assertEquals("Monkeypatch broke the test: " + stderr, 1, runner.getPassedTestsCount());
+        }
+      });
+  }
+
   // Ensure slow test is not run when -m "not slow" is provided
   @Test
   public void testMarkerWithSpaces() throws Exception {