diff --git a/base/base_tests/string_utils_test.cpp b/base/base_tests/string_utils_test.cpp
index 6e8c36a6b7..564e51fcbe 100644
--- a/base/base_tests/string_utils_test.cpp
+++ b/base/base_tests/string_utils_test.cpp
@@ -348,14 +348,14 @@ void TestIter(string const & s, char const * delims, vector<string> const & toke
   strings::SimpleTokenizer it(s, delims);
   for (size_t i = 0; i < tokens.size(); ++i)
   {
-    TEST_EQUAL(true, it, (s, delims, i));
+    TEST(it, (s, delims, i));
     TEST_EQUAL(*it, tokens[i], (s, delims, i));
     ++it;
   }
-  TEST_EQUAL(false, it, (s, delims));
+  TEST(!it, (s, delims));
 
   size_t counter = 0;
-  FunctorTester f = FunctorTester(counter, tokens);
+  FunctorTester f(counter, tokens);
   strings::Tokenize(s, delims, f);
   TEST_EQUAL(counter, tokens.size(), ());
 }
@@ -366,11 +366,11 @@ void TestIterWithEmptyTokens(string const & s, char const * delims, vector<strin
 
   for (size_t i = 0; i < tokens.size(); ++i)
   {
-    TEST_EQUAL(true, it, (s, delims, i));
+    TEST(it, (s, delims, i));
     TEST_EQUAL(*it, tokens[i], (s, delims, i));
     ++it;
   }
-  TEST_EQUAL(false, it, (s, delims));
+  TEST(!it, (s, delims));
 }
 
 UNIT_TEST(SimpleTokenizer)
@@ -420,38 +420,38 @@ UNIT_TEST(SimpleTokenizer)
 
   {
     string const s = "";
-    vector<string> tokens = {""};
+    vector<string> const tokens = {""};
     TestIterWithEmptyTokens(s, ",", tokens);
   }
 
   {
-    string const s = ",";
-    vector<string> tokens = {"", ""};
-    TestIterWithEmptyTokens(s, ",", tokens);
+    string const s = ";";
+    vector<string> const tokens = {"", ""};
+    TestIterWithEmptyTokens(s, ";", tokens);
   }
 
   {
-    string const s = ",,";
-    vector<string> tokens = {"", "", ""};
-    TestIterWithEmptyTokens(s, ",", tokens);
+    string const s = ";;";
+    vector<string> const tokens = {"", "", ""};
+    TestIterWithEmptyTokens(s, ";", tokens);
   }
 
   {
     string const s = "Hello, World!";
-    vector<string> tokens = {s};
+    vector<string> const tokens = {s};
     TestIterWithEmptyTokens(s, "", tokens);
   }
 
   {
     string const s = "Hello, World!";
-    vector<string> tokens = {"Hello", " World", ""};
+    vector<string> const tokens = {"Hello", " World", ""};
     TestIterWithEmptyTokens(s, ",!", tokens);
   }
 
   {
-    string const s = ",a,b,,c,d,";
-    vector<string> tokens = {"", "a", "b", "", "c", "d", ""};
-    TestIterWithEmptyTokens(s, ",", tokens);
+    string const s = ";a;b;;c;d;";
+    vector<string> const tokens = {"", "a", "b", "", "c", "d", ""};
+    TestIterWithEmptyTokens(s, ";", tokens);
   }
 }
 
diff --git a/base/string_utils.hpp b/base/string_utils.hpp
index 33b7af7d2d..c114748369 100644
--- a/base/string_utils.hpp
+++ b/base/string_utils.hpp
@@ -113,8 +113,8 @@ public:
     Move();
   }
 
-  // Use default-constructed iterator for operator == to determine an
-  // end of a token stream.
+  // Use default-constructed iterator for operator == to determine the
+  // end of the token stream.
   TokenizeIterator() = default;
 
   string operator*() const
@@ -137,11 +137,16 @@ public:
     return *this;
   }
 
-  // Same as operator bool() in expression it == end(...).
-  bool operator==(TokenizeIterator const &) { return !(*this); }
+  bool operator==(TokenizeIterator const & rhs) const
+  {
+    if (!*this && !rhs)
+      return true;
+    if (*this && rhs)
+      return m_start == rhs.m_start && m_end == rhs.m_end && m_finish == rhs.m_finish;
+    return false;
+  }
 
-  // Same as operator bool() in expression it != end(...).
-  bool operator!=(TokenizeIterator const &) { return (*this); }
+  bool operator!=(TokenizeIterator const & rhs) const { return !(*this == rhs); }
 
 private:
   void Move()
@@ -155,9 +160,21 @@ private:
       ++m_end;
   }
 
+  // Token is defined as a pair (|m_start|, |m_end|), where:
+  //
+  // * m_start < m_end
+  // * m_start == begin or m_delimFn(m_start - 1)
+  // * m_end == m_finish or m_delimFn(m_end)
+  // * for all i from [m_start, m_end): !m_delimFn(i)
+  //
+  // This version of TokenizeIterator iterates over all tokens and
+  // keeps the invariant above.
   TIt m_start;
   TIt m_end;
+
+  // The end of the string the iterator iterates over.
   TIt m_finish;
+
   TDelimFn m_delimFn;
 };
 
@@ -179,8 +196,16 @@ public:
       ++m_end;
   }
 
-  // Use default-constructed iterator for operator == to determine an
-  // end of a token stream.
+  // *NOTE* |s| must be not temporary!
+  TokenizeIterator(UniString const & s, TDelimFn const & delimFn)
+    : m_start(s.begin()), m_end(s.begin()), m_finish(s.end()), m_delimFn(delimFn), m_finished(false)
+  {
+    while (m_end != m_finish && !m_delimFn(*m_end))
+      ++m_end;
+  }
+
+  // Use default-constructed iterator for operator == to determine the
+  // end of the token stream.
   TokenizeIterator() = default;
 
   string operator*() const
@@ -203,11 +228,19 @@ public:
     return *this;
   }
 
-  // Same as operator bool() in expression it == end(...).
-  bool operator==(TokenizeIterator const &) { return !(*this); }
+  bool operator==(TokenizeIterator const & rhs) const
+  {
+    if (!*this && !rhs)
+      return true;
+    if (*this && rhs)
+    {
+      return m_start == rhs.m_start && m_end == rhs.m_end && m_finish == rhs.m_finish &&
+             m_finished == rhs.m_finished;
+    }
+    return false;
+  }
 
-  // Same as operator bool() in expression it != end(...).
-  bool operator!=(TokenizeIterator const &) { return (*this); }
+  bool operator!=(TokenizeIterator const & rhs) const { return !(*this == rhs); }
 
 private:
   void Move()
@@ -228,10 +261,25 @@ private:
       ++m_end;
   }
 
+  // Token is defined as a pair (|m_start|, |m_end|), where:
+  //
+  // * m_start <= m_end
+  // * m_start == begin or m_delimFn(m_start - 1)
+  // * m_end == m_finish or m_delimFn(m_end)
+  // * for all i from [m_start, m_end): !m_delimFn(i)
+  //
+  // This version of TokenizeIterator iterates over all tokens and
+  // keeps the invariant above.
   TIt m_start;
   TIt m_end;
+
+  // The end of the string the iterator iterates over.
   TIt m_finish;
+
   TDelimFn m_delimFn;
+
+  // When true, iterator is at the end position and is not valid
+  // anymore.
   bool m_finished;
 };