diff --git a/CMakeLists_files.cmake b/CMakeLists_files.cmake
index 755d331a..db726d70 100644
--- a/CMakeLists_files.cmake
+++ b/CMakeLists_files.cmake
@@ -158,6 +158,7 @@ list (APPEND MAIN_SOURCE_FILES
 # find tests -name '*.cpp' -a ! -wholename '*/not-unit/*' -printf '\t%p\n' | sort
 list (APPEND TEST_SOURCE_FILES
   tests/test_writenumwells.cpp
+        tests/test_readWriteWellStateData.cpp
 	tests/test_EclipseWriter.cpp
 	tests/test_EclipseWriteRFTHandler.cpp
 	tests/test_compressedpropertyaccess.cpp
diff --git a/tests/test_readWriteWellStateData.cpp b/tests/test_readWriteWellStateData.cpp
new file mode 100644
index 00000000..fede0ea8
--- /dev/null
+++ b/tests/test_readWriteWellStateData.cpp
@@ -0,0 +1,273 @@
+
+/*
+  Copyright 2014 Statoil IT
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "config.h"
+
+#if HAVE_DYNAMIC_BOOST_TEST
+#define BOOST_TEST_DYN_LINK
+#endif
+
+#define BOOST_TEST_MODULE EclipseWriter
+#include <boost/test/unit_test.hpp>
+
+#include <opm/core/io/eclipse/EclipseWriter.hpp>
+#include <opm/core/io/eclipse/EclipseReader.hpp>
+#include <opm/core/grid/GridManager.hpp>
+#include <opm/core/props/phaseUsageFromDeck.hpp>
+#include <opm/core/simulator/BlackoilState.hpp>
+#include <opm/core/simulator/WellState.hpp>
+#include <opm/core/simulator/SimulatorTimer.hpp>
+#include <opm/core/utility/parameters/ParameterGroup.hpp>
+#include <opm/core/wells.h>
+
+#include <opm/parser/eclipse/Parser/Parser.hpp>
+#include <opm/parser/eclipse/Deck/Deck.hpp>
+#include <opm/parser/eclipse/EclipseState/Schedule/Schedule.hpp>
+#include <opm/parser/eclipse/EclipseState/Schedule/Well.hpp>
+#include <opm/parser/eclipse/EclipseState/Grid/EclipseGrid.hpp>
+#include <opm/core/wells/WellsManager.hpp>
+#include <opm/core/grid/GridManager.hpp>
+#include <opm/core/props/IncompPropertiesFromDeck.hpp>
+#include <opm/core/simulator/TwophaseState.hpp>
+
+// ERT stuff
+#include <ert/ecl/ecl_kw.h>
+#include <ert/ecl/ecl_file.h>
+#include <ert/ecl/ecl_kw_magic.h>
+#include <ert/ecl_well/well_info.h>
+#include <ert/ecl_well/well_state.h>
+#include <ert/util/test_work_area.h>
+
+#include <string.h>
+
+//
+std::string input =
+           "RUNSPEC\n"
+           "OIL\n"
+           "GAS\n"
+           "WATER\n"
+           "DIMENS\n"
+           " 10 10 10 /\n"
+
+           "GRID\n"
+           "DXV\n"
+           "10*0.25 /\n"
+           "DYV\n"
+           "10*0.25 /\n"
+           "DZV\n"
+           "10*0.25 /\n"
+           "TOPS\n"
+           "100*0.25 /\n"
+           "\n"
+
+           "START             -- 0 \n"
+           "1 NOV 1979 / \n"
+
+           "SCHEDULE\n"
+           "DATES             -- 1\n"
+           " 10  OKT 2008 / \n"
+           "/\n"
+           "WELSPECS\n"
+           "    'OP_1'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "    'OP_2'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_1'  9  9   1   1 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           " 'OP_2'  9  9   2   2 'OPEN' 1*   46.825   0.311  4332.346 1*  1*  'X'  22.123 / \n"
+           " 'OP_1'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_1' 'OPEN' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+           "WCONINJE\n"
+               "'OP_2' 'GAS' 'OPEN' 'RATE' 100 200 400 /\n"
+           "/\n"
+
+           "DATES             -- 2\n"
+           " 20  JAN 2011 / \n"
+           "/\n"
+           "WELSPECS\n"
+           "    'OP_3'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_3'  9  9   1   1 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_3' 'OPEN' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+
+           "DATES             -- 3\n"
+           " 15  JUN 2013 / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_2'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           " 'OP_1'  9  9   7  7 'SHUT' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+
+           "DATES             -- 4\n"
+           " 22  APR 2014 / \n"
+           "/\n"
+           "WELSPECS\n"
+           "    'OP_4'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_4'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           " 'OP_3'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_4' 'OPEN' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+
+           "DATES             -- 5\n"
+           " 30  AUG 2014 / \n"
+           "/\n"
+           "WELSPECS\n"
+           "    'OP_5'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_5'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_5' 'OPEN' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+
+           "DATES             -- 6\n"
+           " 15  SEP 2014 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_3' 'SHUT' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+
+           "DATES             -- 7\n"
+           " 9  OCT 2014 / \n"
+           "/\n"
+           "WELSPECS\n"
+           "    'OP_6'       'OP'   9   9 1*     'OIL' 1*      1*  1*   1*  1*   1*  1*  / \n"
+           "/\n"
+           "COMPDAT\n"
+           " 'OP_6'  9  9   3  9 'OPEN' 1*   32.948   0.311  3047.839 1*  1*  'X'  22.100 / \n"
+           "/\n"
+           "WCONPROD\n"
+               "'OP_6' 'OPEN' 'ORAT' 20000  4* 1000 /\n"
+           "/\n"
+           "TSTEP            -- 8\n"
+           "10 /"
+           "/\n";
+
+std::shared_ptr<Opm::BlackoilState> createBlackOilState(Opm::EclipseGridConstPtr eclGrid) {
+
+  std::shared_ptr<Opm::GridManager> ourFineGridManagerPtr(new Opm::GridManager(eclGrid));
+  std::shared_ptr<Opm::BlackoilState> blackoilState(new Opm::BlackoilState);
+  blackoilState->init(*ourFineGridManagerPtr->c_grid(), 3);
+
+  return blackoilState;
+}
+
+Opm::EclipseWriterPtr createEclipseWriter(Opm::DeckConstPtr deck,
+                                          Opm::EclipseStatePtr eclipseState,
+                                          std::string& eclipse_data_filename) {
+
+  Opm::parameter::ParameterGroup params;
+  params.insertParameter("deck_filename", eclipse_data_filename);
+
+  const Opm::PhaseUsage phaseUsage = Opm::phaseUsageFromDeck(deck);
+
+  Opm::EclipseWriterPtr eclWriter(new Opm::EclipseWriter(params,
+                                                         eclipseState,
+                                                         phaseUsage,
+                                                         eclipseState->getEclipseGrid()->getCartesianSize(),
+                                                         0));
+  return eclWriter;
+}
+
+void setValuesInWellState(std::shared_ptr<Opm::WellState> wellState){
+    wellState->bhp()[0] = 1.23;
+    wellState->bhp()[1] = 2.34;
+
+    wellState->temperature()[0] = 3.45;
+    wellState->temperature()[1] = 4.56;
+
+    wellState->wellRates()[0] = 5.67;
+    wellState->wellRates()[1] = 6.78;
+    wellState->wellRates()[2] = 7.89;
+    wellState->wellRates()[3] = 8.90;
+    wellState->wellRates()[4] = 9.01;
+    wellState->wellRates()[5] = 10.12;
+
+    wellState->perfPress()[0] = 20.41;
+    wellState->perfPress()[1] = 21.19;
+    wellState->perfPress()[2] = 22.41;
+    wellState->perfPress()[3] = 23.19;
+    wellState->perfPress()[4] = 24.41;
+    wellState->perfPress()[5] = 25.19;
+    wellState->perfPress()[6] = 26.41;
+    wellState->perfPress()[7] = 27.19;
+    wellState->perfPress()[8] = 28.41;
+
+    wellState->perfRates()[0] = 30.45;
+    wellState->perfRates()[1] = 31.19;
+    wellState->perfRates()[2] = 32.45;
+    wellState->perfRates()[3] = 33.19;
+    wellState->perfRates()[4] = 34.45;
+    wellState->perfRates()[5] = 35.19;
+    wellState->perfRates()[6] = 36.45;
+    wellState->perfRates()[7] = 37.19;
+    wellState->perfRates()[8] = 38.45;
+}
+
+BOOST_AUTO_TEST_CASE(EclipseReadWriteWellStateData)
+{
+    std::string eclipse_data_filename    = "TestWellState.DATA";
+    std::string eclipse_restart_filename = "TESTWELLSTATE.UNRST";
+    test_work_area_type * test_area = test_work_area_alloc("EclipseReadWriteWellStateData");
+
+    Opm::Parser parser;
+    Opm::DeckConstPtr deck = parser.parseString(input);
+    Opm::EclipseStatePtr  eclipseState(new Opm::EclipseState(deck));
+    Opm::EclipseWriterPtr eclipseWriter = createEclipseWriter(deck, eclipseState, eclipse_data_filename);
+
+    std::shared_ptr<Opm::SimulatorTimer> simTimer( new Opm::SimulatorTimer() );
+    simTimer->init(eclipseState->getSchedule()->getTimeMap());
+    eclipseWriter->writeInit(*simTimer);
+    std::shared_ptr<Opm::WellState> wellState(new Opm::WellState());
+
+    Opm::GridManager gridManager(deck);
+    Opm::WellsManager wellsManager(eclipseState, 1, *gridManager.c_grid(), NULL);
+    const Wells* wells = wellsManager.c_wells();
+    std::shared_ptr<Opm::BlackoilState> blackoilState = createBlackOilState(eclipseState->getEclipseGrid());
+    wellState->init(wells, *blackoilState);
+
+    setValuesInWellState(wellState);
+    simTimer->setCurrentStepNum(1);
+    eclipseWriter->writeTimeStep(*simTimer, *blackoilState, *wellState);
+
+    const char * test_area_path = test_work_area_get_cwd(test_area);
+    std::string slash = "/";
+    std::string restart_filename = test_area_path + slash + eclipse_restart_filename;
+    std::shared_ptr<Opm::WellState> wellStateRestored(new Opm::WellState());
+    wellStateRestored->init(wells, *blackoilState);
+    Opm::restoreOPM_XWELKeyword(restart_filename, 1, *wellStateRestored);
+
+    BOOST_CHECK_EQUAL_COLLECTIONS(wellState->bhp().begin(), wellState->bhp().end(), wellStateRestored->bhp().begin(), wellStateRestored->bhp().end());
+    BOOST_CHECK_EQUAL_COLLECTIONS(wellState->temperature().begin(), wellState->temperature().end(), wellStateRestored->temperature().begin(), wellStateRestored->temperature().end());
+    BOOST_CHECK_EQUAL_COLLECTIONS(wellState->wellRates().begin(), wellState->wellRates().end(), wellStateRestored->wellRates().begin(), wellStateRestored->wellRates().end());
+    BOOST_CHECK_EQUAL_COLLECTIONS(wellState->perfRates().begin(), wellState->perfRates().end(), wellStateRestored->perfRates().begin(), wellStateRestored->perfRates().end());
+    BOOST_CHECK_EQUAL_COLLECTIONS(wellState->perfPress().begin(), wellState->perfPress().end(), wellStateRestored->perfPress().begin(), wellStateRestored->perfPress().end());
+
+    test_work_area_free(test_area);
+}