diff --git a/include/etl/basic_format_spec.h b/include/etl/basic_format_spec.h
index d5a885ff..80e9870e 100644
--- a/include/etl/basic_format_spec.h
+++ b/include/etl/basic_format_spec.h
@@ -211,15 +211,22 @@ namespace etl
     /// Upper case (for hex) = true
     /// Left Justified = false
     //***************************************************************************
-    basic_format_spec()
+    ETL_CONSTEXPR basic_format_spec()
+      : base_(10U)
+      , width_(0U)
+      , precision_(0U)
+      , upper_case_(false)
+      , left_justified_(false)
+      , boolalpha_(false)
+      , show_base_(false)
+      , fill_(typename TString::value_type(' '))
     {
-      clear();
     }
 
     //***************************************************************************
     /// Clears the format spec back to default.
     //***************************************************************************
-    void clear()
+    ETL_CONSTEXPR void clear()
     {
       base_           = 10U;
       width_          = 0U;
@@ -235,7 +242,7 @@ namespace etl
     /// Sets the base.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& base(uint32_t b)
+    ETL_CONSTEXPR basic_format_spec& base(uint32_t b)
     {
       base_ = static_cast<uint_least8_t>(b);
       return *this;
@@ -245,7 +252,7 @@ namespace etl
     /// Sets the base to binary.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& binary()
+    ETL_CONSTEXPR basic_format_spec& binary()
     {
       base(2);
       return *this;
@@ -255,7 +262,7 @@ namespace etl
     /// Sets the base to octal.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& octal()
+    ETL_CONSTEXPR basic_format_spec& octal()
     {
       base(8);
       return *this;
@@ -265,7 +272,7 @@ namespace etl
     /// Sets the base to decimal.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& decimal()
+    ETL_CONSTEXPR basic_format_spec& decimal()
     {
       base(10);
       return *this;
@@ -275,7 +282,7 @@ namespace etl
     /// Sets the base to hex.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& hex()
+    ETL_CONSTEXPR basic_format_spec& hex()
     {
       base(16);
       return *this;
@@ -284,7 +291,7 @@ namespace etl
     //***************************************************************************
     /// Gets the base.
     //***************************************************************************
-    uint32_t get_base() const
+    ETL_CONSTEXPR uint32_t get_base() const
     {
       return base_;
     }
@@ -293,7 +300,7 @@ namespace etl
     /// Sets the show base flag.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& show_base(bool b)
+    ETL_CONSTEXPR basic_format_spec& show_base(bool b)
     {
       show_base_ = b;
       return *this;
@@ -302,7 +309,7 @@ namespace etl
     //***************************************************************************
     /// Gets the show base flag.
     //***************************************************************************
-    bool is_show_base() const
+    ETL_CONSTEXPR bool is_show_base() const
     {
       return show_base_;
     }
@@ -311,7 +318,7 @@ namespace etl
     /// Sets the width.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& width(uint32_t w)
+    ETL_CONSTEXPR basic_format_spec& width(uint32_t w)
     {
       width_ = static_cast<uint_least8_t>(w);
       return *this;
@@ -320,7 +327,7 @@ namespace etl
     //***************************************************************************
     /// Gets the width.
     //***************************************************************************
-    uint32_t get_width() const
+    ETL_CONSTEXPR uint32_t get_width() const
     {
       return width_;
     }
@@ -329,7 +336,7 @@ namespace etl
     /// Sets the precision.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& precision(uint32_t p)
+    ETL_CONSTEXPR basic_format_spec& precision(uint32_t p)
     {
       precision_ = static_cast<uint_least8_t>(p);
       return *this;
@@ -338,7 +345,7 @@ namespace etl
     //***************************************************************************
     /// Gets the precision.
     //***************************************************************************
-    uint32_t get_precision() const
+    ETL_CONSTEXPR uint32_t get_precision() const
     {
       return precision_;
     }
@@ -347,7 +354,7 @@ namespace etl
     /// Sets the upper case flag.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& upper_case(bool u)
+    ETL_CONSTEXPR basic_format_spec& upper_case(bool u)
     {
       upper_case_ = u;
       return *this;
@@ -356,7 +363,7 @@ namespace etl
     //***************************************************************************
     /// Gets the upper case flag.
     //***************************************************************************
-    bool is_upper_case() const
+    ETL_CONSTEXPR bool is_upper_case() const
     {
       return upper_case_;
     }
@@ -365,7 +372,7 @@ namespace etl
     /// Sets the fill character.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& fill(typename TString::value_type c)
+    ETL_CONSTEXPR basic_format_spec& fill(typename TString::value_type c)
     {
       fill_ = c;
       return *this;
@@ -374,7 +381,7 @@ namespace etl
     //***************************************************************************
     /// Gets the fill character.
     //***************************************************************************
-    typename TString::value_type get_fill() const
+    ETL_CONSTEXPR typename TString::value_type get_fill() const
     {
       return fill_;
     }
@@ -383,7 +390,7 @@ namespace etl
     /// Sets the left justify flag.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& left()
+    ETL_CONSTEXPR basic_format_spec& left()
     {
       left_justified_ = true;
       return *this;
@@ -392,7 +399,7 @@ namespace etl
     //***************************************************************************
     /// Gets the left justify flag.
     //***************************************************************************
-    bool is_left() const
+    ETL_CONSTEXPR bool is_left() const
     {
       return left_justified_;
     }
@@ -401,7 +408,7 @@ namespace etl
     /// Sets the right justify flag.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& right()
+    ETL_CONSTEXPR basic_format_spec& right()
     {
       left_justified_ = false;
       return *this;
@@ -410,7 +417,7 @@ namespace etl
     //***************************************************************************
     /// Gets the right justify flag.
     //***************************************************************************
-    bool is_right() const
+    ETL_CONSTEXPR bool is_right() const
     {
       return !left_justified_;
     }
@@ -419,7 +426,7 @@ namespace etl
     /// Sets the bool alpha flag.
     /// \return A reference to the basic_format_spec.
     //***************************************************************************
-    basic_format_spec& boolalpha(bool b)
+    ETL_CONSTEXPR basic_format_spec& boolalpha(bool b)
     {
       boolalpha_ = b;
       return *this;
@@ -428,7 +435,7 @@ namespace etl
     //***************************************************************************
     /// Gets the boolalpha flag.
     //***************************************************************************
-    bool is_boolalpha() const
+    ETL_CONSTEXPR bool is_boolalpha() const
     {
       return boolalpha_;
     }
@@ -436,7 +443,7 @@ namespace etl
     //***************************************************************************
     /// Equality operator.
     //***************************************************************************
-    friend bool operator ==(const basic_format_spec& lhs, const basic_format_spec& rhs)
+    ETL_CONSTEXPR friend bool operator ==(const basic_format_spec& lhs, const basic_format_spec& rhs)
     {
       return (lhs.base_ == rhs.base_) &&
              (lhs.width_ == rhs.width_) &&
@@ -451,7 +458,7 @@ namespace etl
     //***************************************************************************
     /// Inequality operator.
     //***************************************************************************
-    friend bool operator !=(const basic_format_spec& lhs, const basic_format_spec& rhs)
+    ETL_CONSTEXPR friend bool operator !=(const basic_format_spec& lhs, const basic_format_spec& rhs)
     {
       return !(lhs == rhs);
     }
diff --git a/include/etl/basic_string.h b/include/etl/basic_string.h
index 4f4df6d2..17023675 100644
--- a/include/etl/basic_string.h
+++ b/include/etl/basic_string.h
@@ -602,6 +602,13 @@ namespace etl
       }
 #endif
 
+#if ETL_STRING_CLEAR_AFTER_USE_ENABLED
+      if (other.is_secure())
+      {
+        set_secure();
+      }
+#endif
+
       cleanup();
     }
 
@@ -622,6 +629,24 @@ namespace etl
       ETL_ASSERT(subposition <= other.size(), ETL_ERROR(string_out_of_bounds));
 
       assign(other.begin() + subposition, sublength);
+
+#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
+      if (other.is_truncated())
+      {
+        this->set_truncated(true);
+
+#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
+        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
+#endif
+      }
+#endif
+
+#if ETL_STRING_CLEAR_AFTER_USE_ENABLED
+      if (other.is_secure())
+      {
+        set_secure();
+      }
+#endif
     }
 
     //*********************************************************************
diff --git a/include/etl/math_constants.h b/include/etl/math_constants.h
index bc76cfcd..29595399 100644
--- a/include/etl/math_constants.h
+++ b/include/etl/math_constants.h
@@ -35,16 +35,16 @@ namespace etl
 {
   namespace math
   {
-    const double pi               = 3.14159265358979;
-    const double pi_reciprocal    = 0.31830988618379;
-    const double pi_squared       = 9.86960440108936;
-    const double e                = 2.71828182845905;
-    const double e_reciprocal     = 0.36787944117144;
-    const double e_squared        = 7.38905609893065;
-    const double root2            = 1.41421356237310;
-    const double root2_reciprocal = 0.70710678118655;
-    const double euler            = 0.57721566490153;
-    const double golden_ratio     = 1.61803398874989;
+    ETL_CONSTANT double pi               = 3.14159265358979;
+    ETL_CONSTANT double pi_reciprocal    = 0.31830988618379;
+    ETL_CONSTANT double pi_squared       = 9.86960440108936;
+    ETL_CONSTANT double e                = 2.71828182845905;
+    ETL_CONSTANT double e_reciprocal     = 0.36787944117144;
+    ETL_CONSTANT double e_squared        = 7.38905609893065;
+    ETL_CONSTANT double root2            = 1.41421356237310;
+    ETL_CONSTANT double root2_reciprocal = 0.70710678118655;
+    ETL_CONSTANT double euler            = 0.57721566490153;
+    ETL_CONSTANT double golden_ratio     = 1.61803398874989;
   }
 }
 
diff --git a/include/etl/nullptr.h b/include/etl/nullptr.h
index a661288f..2e200787 100644
--- a/include/etl/nullptr.h
+++ b/include/etl/nullptr.h
@@ -33,7 +33,7 @@ SOFTWARE.
 
 #include "platform.h"
 
-#if defined(ARDUINO)
+#if defined(ARDUINO) || defined(AVR)
   #include <stddef.h>
 #else
   #include <cstddef>
diff --git a/include/etl/string.h b/include/etl/string.h
index e7924371..361c2024 100644
--- a/include/etl/string.h
+++ b/include/etl/string.h
@@ -100,23 +100,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    string(const etl::istring& other, size_t position, size_t length_ = npos)
+    string(const etl::istring& other, size_t position, size_t length = npos)
       : istring(reinterpret_cast<value_type*>(&buffer), MAX_SIZE)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
@@ -309,23 +298,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    string_ext(const etl::istring& other, value_type* buffer, size_type buffer_size, size_type position, size_type length_ = npos)
+    string_ext(const etl::istring& other, value_type* buffer, size_type buffer_size, size_type position, size_type length = npos)
       : istring(buffer, buffer_size - 1U)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
diff --git a/include/etl/u16string.h b/include/etl/u16string.h
index d3351a9d..e79d9219 100644
--- a/include/etl/u16string.h
+++ b/include/etl/u16string.h
@@ -98,23 +98,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    u16string(const etl::iu16string& other, size_type position, size_type length_ = npos)
+    u16string(const etl::iu16string& other, size_type position, size_type length = npos)
       : iu16string(reinterpret_cast<value_type*>(&buffer), MAX_SIZE)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
@@ -292,23 +281,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    u16string_ext(const etl::iu16string& other, value_type* buffer, size_type buffer_size, size_type position, size_type length_ = npos)
+    u16string_ext(const etl::iu16string& other, value_type* buffer, size_type buffer_size, size_type position, size_type length = npos)
       : iu16string(buffer, buffer_size - 1U)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(u16string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
diff --git a/include/etl/u32string.h b/include/etl/u32string.h
index 7a0ad002..40ab1ca1 100644
--- a/include/etl/u32string.h
+++ b/include/etl/u32string.h
@@ -98,23 +98,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    u32string(const etl::iu32string& other, size_type position, size_type length_ = npos)
+    u32string(const etl::iu32string& other, size_type position, size_type length = npos)
       : iu32string(reinterpret_cast<value_type*>(&buffer), MAX_SIZE)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
@@ -292,23 +281,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    u32string_ext(const etl::iu32string& other, value_type* buffer, size_type buffer_size, size_type position, size_type length_ = npos)
+    u32string_ext(const etl::iu32string& other, value_type* buffer, size_type buffer_size, size_type position, size_type length = npos)
       : iu32string(buffer, buffer_size - 1U)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(u32string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
diff --git a/include/etl/version.h b/include/etl/version.h
index 64d6a44a..bce0a92e 100644
--- a/include/etl/version.h
+++ b/include/etl/version.h
@@ -38,7 +38,7 @@ SOFTWARE.
 ///\ingroup utilities
 
 #define ETL_VERSION_MAJOR 19
-#define ETL_VERSION_MINOR  1
+#define ETL_VERSION_MINOR  2
 #define ETL_VERSION_PATCH  0
 #define ETL_VERSION       ETL_STRINGIFY(ETL_VERSION_MAJOR) "." ETL_STRINGIFY(ETL_VERSION_MINOR) "." ETL_STRINGIFY(ETL_VERSION_PATCH)
 #define ETL_VERSION_W     ETL_STRINGIFY(ETL_VERSION_MAJOR) L"." ETL_STRINGIFY(ETL_VERSION_MINOR) L"." ETL_STRINGIFY(ETL_VERSION_PATCH)
diff --git a/include/etl/wstring.h b/include/etl/wstring.h
index a86b24b5..802e6dfb 100644
--- a/include/etl/wstring.h
+++ b/include/etl/wstring.h
@@ -98,23 +98,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    wstring(const etl::iwstring& other, size_type position, size_type length_ = npos)
+    wstring(const etl::iwstring& other, size_type position, size_type length = npos)
       : iwstring(reinterpret_cast<value_type*>(&buffer), MAX_SIZE)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(string_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
@@ -292,23 +281,12 @@ namespace etl
     ///\param position The position of the first character.
     ///\param length   The number of characters. Default = npos.
     //*************************************************************************
-    wstring_ext(const etl::iwstring& other, value_type* buffer, size_type buffer_size, size_type position, size_type length_ = npos)
+    wstring_ext(const etl::iwstring& other, value_type* buffer, size_type buffer_size, size_type position, size_type length = npos)
       : iwstring(buffer, buffer_size - 1U)
     {
       ETL_ASSERT(position < other.size(), ETL_ERROR(string_out_of_bounds));
 
-      this->assign(other.begin() + position, other.begin() + position + length_);
-
-#if ETL_STRING_TRUNCATION_CHECKS_ENABLED
-      if (other.is_truncated())
-      {
-        this->set_truncated(true);
-
-#if defined(ETL_STRING_TRUNCATION_IS_ERROR)
-        ETL_ALWAYS_ASSERT(ETL_ERROR(wstring_truncation));
-#endif
-      }
-#endif
+      this->assign(other, position, length);
     }
 
     //*************************************************************************
diff --git a/library.json b/library.json
index 32bead34..28ed610d 100644
--- a/library.json
+++ b/library.json
@@ -1,6 +1,6 @@
 {
   "name": "Embedded Template Library",
-  "version": "19.1.0",
+  "version": "19.2.0",
   "author s": {
     "name": "John Wellbelove",
     "email": "john.wellbelove@etlcpp.com"
diff --git a/library.properties b/library.properties
index d91061e6..3625eedf 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=Embedded Template Library
-version=19.1.0
+version=19.2.0
 author= John Wellbelove <john.wellbelove@etlcpp.com>
 maintainer=John Wellbelove <john.wellbelove@etlcpp.com>
 license=MIT
diff --git a/support/Release notes.txt b/support/Release notes.txt
index c0f99551..7b0bb26e 100644
--- a/support/Release notes.txt	
+++ b/support/Release notes.txt	
@@ -1,3 +1,9 @@
+===============================================================================
+19.2.0
+Security flag for a string is copied on assignment or copy constructor.
+etl::format_spec may now be a constexpr.
+Added AVR check to nullptr.h
+
 ===============================================================================
 19.1.0
 Refactor of etl::buffer_descriptors interface.
diff --git a/test/test_format_spec.cpp b/test/test_format_spec.cpp
new file mode 100644
index 00000000..471ab91b
--- /dev/null
+++ b/test/test_format_spec.cpp
@@ -0,0 +1,105 @@
+/******************************************************************************
+The MIT License(MIT)
+
+Embedded Template Library.
+https://github.com/ETLCPP/etl
+https://www.etlcpp.com
+
+Copyright(c) 2019 jwellbelove
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files(the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions :
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+******************************************************************************/
+
+#include "UnitTest++/UnitTest++.h"
+
+#include <ostream>
+#include <sstream>
+#include <iomanip>
+
+#include "etl/format_spec.h"
+#include "etl/wformat_spec.h"
+#include "etl/u16format_spec.h"
+#include "etl/u32format_spec.h"
+
+namespace
+{
+  SUITE(test_format_spec)
+  {
+    //*************************************************************************
+    TEST(test_default_format)
+    {
+      etl::format_spec format;
+
+      CHECK_EQUAL(10,    format.get_base());
+      CHECK_EQUAL(' ',   format.get_fill());
+      CHECK_EQUAL(0,     format.get_precision());
+      CHECK_EQUAL(0,     format.get_width());
+      CHECK_EQUAL(false, format.is_boolalpha());
+      CHECK_EQUAL(false, format.is_left());
+      CHECK_EQUAL(true,  format.is_right());
+      CHECK_EQUAL(false, format.is_show_base());
+      CHECK_EQUAL(false, format.is_upper_case());
+    }
+
+    //*************************************************************************
+    TEST(test_format)
+    {
+      etl::format_spec format;
+
+      format.base(16).boolalpha(true).fill('?').left().precision(6).show_base(true).upper_case(true).width(10);
+
+      CHECK_EQUAL(16,    format.get_base());
+      CHECK_EQUAL('?',   format.get_fill());
+      CHECK_EQUAL(6,     format.get_precision());
+      CHECK_EQUAL(10,    format.get_width());
+      CHECK_EQUAL(true,  format.is_boolalpha());
+      CHECK_EQUAL(true,  format.is_left());
+      CHECK_EQUAL(false, format.is_right());
+      CHECK_EQUAL(true,  format.is_show_base());
+      CHECK_EQUAL(true,  format.is_upper_case());
+    }
+
+    //*************************************************************************
+    TEST(test_format_constexpr)
+    {
+      constexpr etl::format_spec format = etl::format_spec().base(16).boolalpha(true).fill('?').left().precision(6).show_base(true).upper_case(true).width(10);
+
+      constexpr int  base       = format.get_base();
+      constexpr char fill       = format.get_fill();
+      constexpr int  precision  = format.get_precision();
+      constexpr int  width      = format.get_width();
+      constexpr bool boolalpha  = format.is_boolalpha();
+      constexpr bool left       = format.is_left();
+      constexpr bool right      = format.is_right();
+      constexpr bool show_base  = format.is_show_base();
+      constexpr bool upper_case = format.is_upper_case();
+
+      CHECK_EQUAL(16,    base);
+      CHECK_EQUAL('?',   fill);
+      CHECK_EQUAL(6,     precision);
+      CHECK_EQUAL(10,    width);
+      CHECK_EQUAL(true,  boolalpha);
+      CHECK_EQUAL(true,  left);
+      CHECK_EQUAL(false, right);
+      CHECK_EQUAL(true,  show_base);
+      CHECK_EQUAL(true,  upper_case);
+    }
+  };
+}
+
diff --git a/test/test_string_char.cpp b/test/test_string_char.cpp
index 786cb44b..01e1a32f 100644
--- a/test/test_string_char.cpp
+++ b/test/test_string_char.cpp
@@ -4138,6 +4138,25 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      Text text1 = STR("Hello World");
+      text1.set_secure();
+
+      Text text2(text1);
+
+      Text text3;
+      text3 = text1;
+
+      Text text4(text1, 6U, 3U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
+
 #endif
   };
 }
diff --git a/test/test_string_char_external_buffer.cpp b/test/test_string_char_external_buffer.cpp
index 69bd1674..3a3d35d4 100644
--- a/test/test_string_char_external_buffer.cpp
+++ b/test/test_string_char_external_buffer.cpp
@@ -4496,6 +4496,28 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      TextBuffer buffer1;
+      Text text1(STR("Hello World"), buffer1.data(), buffer1.size());
+      text1.set_secure();
+
+      TextBuffer buffer2;
+      Text text2(text1, buffer2.data(), buffer2.size());
+
+      TextBuffer buffer3;
+      Text text3(buffer3.data(), buffer3.size());
+      text3 = text1;
+
+      TextBuffer buffer4;
+      Text text4(text1, buffer4.data(), buffer4.size(), 6U, 2U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
 #endif
   };
 }
diff --git a/test/test_string_u16.cpp b/test/test_string_u16.cpp
index ea4031ff..379d18bf 100644
--- a/test/test_string_u16.cpp
+++ b/test/test_string_u16.cpp
@@ -4138,6 +4138,24 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      Text text1 = STR("Hello World");
+      text1.set_secure();
+
+      Text text2(text1);
+
+      Text text3;
+      text3 = text1;
+
+      Text text4(text1, 6U, 3U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
 #endif
   };
 }
diff --git a/test/test_string_u16_external_buffer.cpp b/test/test_string_u16_external_buffer.cpp
index d3339e61..4673ab2c 100644
--- a/test/test_string_u16_external_buffer.cpp
+++ b/test/test_string_u16_external_buffer.cpp
@@ -4496,6 +4496,28 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      TextBuffer buffer1;
+      Text text1(STR("Hello World"), buffer1.data(), buffer1.size());
+      text1.set_secure();
+
+      TextBuffer buffer2;
+      Text text2(text1, buffer2.data(), buffer2.size());
+
+      TextBuffer buffer3;
+      Text text3(buffer3.data(), buffer3.size());
+      text3 = text1;
+
+      TextBuffer buffer4;
+      Text text4(text1, buffer4.data(), buffer4.size(), 6U, 2U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
 #endif
   };
 }
diff --git a/test/test_string_u32.cpp b/test/test_string_u32.cpp
index ab3e7775..4e011676 100644
--- a/test/test_string_u32.cpp
+++ b/test/test_string_u32.cpp
@@ -4138,6 +4138,24 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      Text text1 = STR("Hello World");
+      text1.set_secure();
+
+      Text text2(text1);
+
+      Text text3;
+      text3 = text1;
+
+      Text text4(text1, 6U, 3U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
 #endif
   };
 }
diff --git a/test/test_string_u32_external_buffer.cpp b/test/test_string_u32_external_buffer.cpp
index e4343826..859dbfcf 100644
--- a/test/test_string_u32_external_buffer.cpp
+++ b/test/test_string_u32_external_buffer.cpp
@@ -4481,20 +4481,25 @@ namespace
     }
 
     //*************************************************************************
-    TEST_FIXTURE(SetupFixture, test_secure_after_clear)
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
     {
-      TextBuffer buffer;
-      Text text(buffer.data(), buffer.size());
-      text.set_secure();
-      text.assign(STR("ABCDEF"));
+      TextBuffer buffer1;
+      Text text1(STR("Hello World"), buffer1.data(), buffer1.size());
+      text1.set_secure();
 
-      Text::pointer pb = text.begin();
-      Text::pointer pe = text.end();
+      TextBuffer buffer2;
+      Text text2(text1, buffer2.data(), buffer2.size());
 
-      text.clear();
+      TextBuffer buffer3;
+      Text text3(buffer3.data(), buffer3.size());
+      text3 = text1;
 
-      // Check there no non-zero values in the remainder of the string.
-      CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
+      TextBuffer buffer4;
+      Text text4(text1, buffer4.data(), buffer4.size(), 6U, 2U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
     }
 #endif
   };
diff --git a/test/test_string_wchar_t.cpp b/test/test_string_wchar_t.cpp
index 7b4d096b..26cbde56 100644
--- a/test/test_string_wchar_t.cpp
+++ b/test/test_string_wchar_t.cpp
@@ -4138,6 +4138,24 @@ namespace
       // Check there no non-zero values in the remainder of the string.
       CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
     }
+
+    //*************************************************************************
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
+    {
+      Text text1 = STR("Hello World");
+      text1.set_secure();
+
+      Text text2(text1);
+
+      Text text3;
+      text3 = text1;
+
+      Text text4(text1, 6U, 3U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
+    }
 #endif
   };
 }
diff --git a/test/test_string_wchar_t_external_buffer.cpp b/test/test_string_wchar_t_external_buffer.cpp
index ed1bceb9..009a48bf 100644
--- a/test/test_string_wchar_t_external_buffer.cpp
+++ b/test/test_string_wchar_t_external_buffer.cpp
@@ -4481,20 +4481,25 @@ namespace
     }
 
     //*************************************************************************
-    TEST_FIXTURE(SetupFixture, test_secure_after_clear)
+    TEST_FIXTURE(SetupFixture, test_secure_flag_after_copy)
     {
-      TextBuffer buffer;
-      Text text(buffer.data(), buffer.size());
-      text.set_secure();
-      text.assign(STR("ABCDEF"));
+      TextBuffer buffer1;
+      Text text1(STR("Hello World"), buffer1.data(), buffer1.size());
+      text1.set_secure();
 
-      Text::pointer pb = text.begin();
-      Text::pointer pe = text.end();
+      TextBuffer buffer2;
+      Text text2(text1, buffer2.data(), buffer2.size());
 
-      text.clear();
+      TextBuffer buffer3;
+      Text text3(buffer3.data(), buffer3.size());
+      text3 = text1;
 
-      // Check there no non-zero values in the remainder of the string.
-      CHECK(std::find_if(pb, pe, [](Text::value_type x) { return x != 0; }) == pe);
+      TextBuffer buffer4;
+      Text text4(text1, buffer4.data(), buffer4.size(), 6U, 2U);
+
+      CHECK(text2.is_secure());
+      CHECK(text3.is_secure());
+      CHECK(text4.is_secure());
     }
 #endif
   };
diff --git a/test/vs2019/etl.vcxproj b/test/vs2019/etl.vcxproj
index 4323d358..2c947ac9 100644
--- a/test/vs2019/etl.vcxproj
+++ b/test/vs2019/etl.vcxproj
@@ -1515,6 +1515,7 @@
     <ClCompile Include="..\test_delegate.cpp" />
     <ClCompile Include="..\test_delegate_service.cpp" />
     <ClCompile Include="..\test_flags.cpp" />
+    <ClCompile Include="..\test_format_spec.cpp" />
     <ClCompile Include="..\test_forward_list_shared_pool.cpp" />
     <ClCompile Include="..\test_bit_stream.cpp" />
     <ClCompile Include="..\test_indirect_vector.cpp" />
diff --git a/test/vs2019/etl.vcxproj.filters b/test/vs2019/etl.vcxproj.filters
index 198c3ed2..36af486d 100644
--- a/test/vs2019/etl.vcxproj.filters
+++ b/test/vs2019/etl.vcxproj.filters
@@ -1424,6 +1424,9 @@
     <ClCompile Include="..\test_atomic_clang_sync.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\test_format_spec.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\..\library.properties">