diff --git a/.github/workflows/intel.yml b/.github/workflows/intel.yml
index 700553cea..08ec15b50 100644
--- a/.github/workflows/intel.yml
+++ b/.github/workflows/intel.yml
@@ -51,7 +51,7 @@ jobs:
           sudo apt-key add GPG-PUB-KEY-INTEL-SW-PRODUCTS.PUB
           echo "deb https://apt.repos.intel.com/oneapi all main" | sudo tee /etc/apt/sources.list.d/oneAPI.list
           sudo apt-get update
-          sudo apt-get install intel-oneapi-dev-utilities intel-oneapi-mpi-devel intel-oneapi-openmp intel-oneapi-compiler-fortran intel-oneapi-compiler-dpcpp-cpp-and-cpp-classic
+          sudo apt-get install intel-oneapi-dev-utilities intel-oneapi-mpi-devel intel-oneapi-compiler-fortran-2023.2.1 intel-oneapi-compiler-dpcpp-cpp-and-cpp-classic-2023.2.1 intel-oneapi-openmp
 
       # Build WW3 spack environment
       - name: install-dependencies-with-spack
diff --git a/.github/workflows/io_gnu.yml b/.github/workflows/io_gnu.yml
new file mode 100644
index 000000000..89acaed0c
--- /dev/null
+++ b/.github/workflows/io_gnu.yml
@@ -0,0 +1,123 @@
+name: io_gnu
+on: [push, pull_request, workflow_dispatch]
+
+# Cancel in-progress workflows when pushing to a branch
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+env:
+  cache_key: gnu11-1
+  CC: gcc-10
+  FC: gfortran-10
+  CXX: g++-10
+
+
+# Split into a steup step, and a WW3 build step which
+# builds multiple switches in a matrix. The setup is run once and
+# the environment is cached so each build of WW3 can share the dependencies.
+
+jobs:
+  setup:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: checkout-ww3
+        if: steps.cache-env.outputs.cache-hit != 'true'
+        uses: actions/checkout@v3
+        with:
+            path: ww3
+      # Cache spack, OASIS, and compiler
+      # No way to flush Action cache, so key may have # appended
+      - name: cache-env
+        id: cache-env
+        uses: actions/cache@v3
+        with:
+          path: |
+            spack
+            ~/.spack
+            work_oasis3-mct
+          key: spack-${{ runner.os }}-${{ env.cache_key }}-${{ hashFiles('ww3/model/ci/spack_gnu.yaml') }}
+
+      # Build WW3 spack environment
+      - name: install-dependencies-with-spack
+        if: steps.cache-env.outputs.cache-hit != 'true'
+        run: |
+          # Install NetCDF, ESMF, g2, etc using Spack
+          sudo apt install cmake
+          git clone -c feature.manyFiles=true https://github.com/JCSDA/spack.git
+          source spack/share/spack/setup-env.sh
+          spack env create ww3-gnu ww3/model/ci/spack_gnu.yaml
+          spack env activate ww3-gnu
+          spack compiler find
+          spack external find cmake
+          spack add mpich@3.4.2
+          spack concretize
+          spack install --dirty -v
+
+      - name: build-oasis
+        if: steps.cache-env.outputs.cache-hit != 'true'
+        run: |
+          source spack/share/spack/setup-env.sh
+          spack env activate ww3-gnu
+          export WWATCH3_DIR=${GITHUB_WORKSPACE}/ww3/model
+          export OASIS_INPUT_PATH=${GITHUB_WORKSPACE}/ww3/regtests/ww3_tp2.14/input/oasis3-mct
+          export OASIS_WORK_PATH=${GITHUB_WORKSPACE}/ww3/regtests/ww3_tp2.14/input/work_oasis3-mct
+          cd ww3/regtests/ww3_tp2.14/input/oasis3-mct/util/make_dir
+          cmake .
+          make VERBOSE=1
+          cp -r ${GITHUB_WORKSPACE}/ww3/regtests/ww3_tp2.14/input/work_oasis3-mct ${GITHUB_WORKSPACE}
+
+  io_gnu:
+    needs: setup
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: install-dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install doxygen gcovr valgrind
+
+      - name: checkout-ww3
+        uses: actions/checkout@v3
+        with:
+            path: ww3
+
+      - name: cache-env
+        id: cache-env
+        uses: actions/cache@v3
+        with:
+          path: |
+            spack
+            ~/.spack
+            work_oasis3-mct
+          key: spack-${{ runner.os }}-${{ env.cache_key }}-${{ hashFiles('ww3/model/ci/spack_gnu.yaml') }}
+
+      - name: build-ww3
+        run: |
+          source spack/share/spack/setup-env.sh
+          spack env activate ww3-gnu
+          set -x
+          cd ww3
+          export CC=mpicc
+          export FC=mpif90
+          export OASISDIR=${GITHUB_WORKSPACE}/work_oasis3-mct
+          mkdir build && cd build
+          pwd
+          echo "${GITHUB_WORKSPACE}"
+          export LD_LIBRARY_PATH="/home/runner/work/WW3/WW3/spack/var/spack/environments/ww3-gnu/.spack-env/view/:$LD_LIBRARY_PATH"
+          which ncdump
+          cmake -DSWITCH=${GITHUB_WORKSPACE}/ww3/model/tests/data/switch.io -DCMAKE_BUILD_TYPE=Debug -DCMAKE_Fortran_FLAGS="-g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0 -Wall -fno-omit-frame-pointer -fsanitize=address" -DCMAKE_C_FLAGS="-g -fprofile-abs-path -fprofile-arcs -ftest-coverage -O0 -Wall -fno-omit-frame-pointer -fsanitize=address" ..
+          make -j2 VERBOSE=1
+          ctest --verbose --output-on-failure --rerun-failed
+          gcovr --root .. -v  --html-details --exclude ../model/tests --exclude CMakeFiles --print-summary -o test-coverage.html &> /dev/null
+        
+      - name: upload-test-coverage
+        uses: actions/upload-artifact@v3
+        with:
+          name: ww3-test-coverage
+          path: |
+            ww3/build/*.html
+            ww3/build/*.css
+
+          
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 58115b3aa..ed3d93075 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,3 +58,10 @@ if(NOT CMAKE_BUILD_TYPE MATCHES "^(Debug|Release|RelWithDebInfo|MinSizeRel)$")
 endif()
 
 add_subdirectory(model)
+
+# Turn on unit testing.
+include(CTest)
+if(BUILD_TESTING)
+  add_subdirectory(model/tests)
+endif()
+
diff --git a/model/CMakeLists.txt b/model/CMakeLists.txt
index febd4f0ab..b7178e664 100644
--- a/model/CMakeLists.txt
+++ b/model/CMakeLists.txt
@@ -1 +1,3 @@
 add_subdirectory(src)
+
+
diff --git a/model/src/w3iopomd.F90 b/model/src/w3iopomd.F90
index 0c15ea8c6..552ef06ed 100644
--- a/model/src/w3iopomd.F90
+++ b/model/src/w3iopomd.F90
@@ -118,6 +118,115 @@ MODULE W3IOPOMD
   CHARACTER(LEN=10), PARAMETER, PRIVATE :: VEROPT = '2021-04-06'
   CHARACTER(LEN=31), PARAMETER, PRIVATE ::                        &
        IDSTR = 'WAVEWATCH III POINT OUTPUT FILE'
+
+  !> Dimension name for the netCDF point output file, for NOPTS, the
+  !> Number of Output Points.
+  character(*), parameter, private :: DNAME_NOPTS = 'NOPTS'
+  
+  !> Dimension name for the netCDF point output file, for NSPEC.
+  character(*), parameter, private :: DNAME_NSPEC = 'NSPEC'
+  
+  !> Dimension name for the netCDF point output file, for VSIZE. This
+  !> is for the vector size for points, which is 2.
+  character(*), parameter, private :: DNAME_VSIZE = 'VSIZE'
+  
+  !> Dimension name for the netCDF point output file, for
+  !> NAMELEN. This is the length of the PTNME strings, which contains
+  !> the names of the points.
+  character(*), parameter, private :: DNAME_NAMELEN = 'NAMELEN'
+  
+  !> Dimension name for the netCDF point output file, for GRDIDLEN,
+  !> this is the length of the GRDID character array.
+  character(*), parameter, private :: DNAME_GRDIDLEN = 'GRDIDLEN'
+
+  !> Variable name for the netCDF point output file, for NK.
+  character(*), parameter, private :: VNAME_NK = 'NK'
+
+  !> Variable name for the netCDF point output file, for MTH.
+  character(*), parameter, private :: VNAME_MTH = 'MTH'
+
+  !> Variable name for the netCDF point output file, for PTLOC.
+  character(*), parameter, private :: VNAME_PTLOC = 'PTLOC'
+
+  !> Variable name for the netCDF point output file, for PTNME.
+  character(*), parameter, private :: VNAME_PTNME = 'PTNME'
+
+  !> Variable name for the netCDF point output file, for IW.
+  character(*), parameter, private :: VNAME_IW = 'IW'
+
+  !> Variable name for the netCDF point output file, for II.
+  character(*), parameter, private :: VNAME_II = 'II'
+
+  !> Variable name for the netCDF point output file, for IL.
+  character(*), parameter, private :: VNAME_IL = 'IL'
+
+  !> Variable name for the netCDF point output file, for DPO.
+  character(*), parameter, private :: VNAME_DPO = 'DPO'
+
+  !> Variable name for the netCDF point output file, for WAO.
+  character(*), parameter, private :: VNAME_WAO = 'WAO'
+
+  !> Variable name for the netCDF point output file, for WDO.
+  character(*), parameter, private :: VNAME_WDO = 'WDO'
+
+  !> Variable name for the netCDF point output file, for TAUAO.
+  character(*), parameter, private :: VNAME_TAUAO = 'TAUAO'
+
+  !> Variable name for the netCDF point output file, for TAIDO.
+  character(*), parameter, private :: VNAME_TAIDO = 'TAIDO'
+
+  !> Variable name for the netCDF point output file, for DAIRO.
+  character(*), parameter, private :: VNAME_DAIRO = 'DAIRO'
+
+  !> Variable name for the netCDF point output file, for ZET_SETO.
+  character(*), parameter, private :: VNAME_ZET_SETO = 'ZET_SETO'
+
+  !> Variable name for the netCDF point output file, for ASO.
+  character(*), parameter, private :: VNAME_ASO = 'ASO'
+
+  !> Variable name for the netCDF point output file, for CAO.
+  character(*), parameter, private :: VNAME_CAO = 'CAO'
+
+  !> Variable name for the netCDF point output file, for CDO.
+  character(*), parameter, private :: VNAME_CDO = 'CDO'
+
+  !> Variable name for the netCDF point output file, for ICEO.
+  character(*), parameter, private :: VNAME_ICEO = 'ICEO'
+
+  !> Variable name for the netCDF point output file, for ICEHO.
+  character(*), parameter, private :: VNAME_ICEHO = 'ICEHO'
+
+  !> Variable name for the netCDF point output file, for ICEFO.
+  character(*), parameter, private :: VNAME_ICEFO = 'ICEFO'
+
+  !> Variable name for the netCDF point output file, for GRDID.
+  character(*), parameter, private :: VNAME_GRDID = 'GRDID'
+
+  !> Variable name for the netCDF point output file, for SPCO.
+  character(*), parameter, private :: VNAME_SPCO = 'SPCO'
+
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
+  
   !/
 CONTAINS
   !/ ------------------------------------------------------------------- /
@@ -1024,6 +1133,454 @@ SUBROUTINE W3IOPE ( A )
     !/
   END SUBROUTINE W3IOPE
 
+  !> Read point output in netCDF format.
+  !>
+  !> @param[out] IOTST Test indictor for reading.
+  !> @param[in] IMOD Model number for W3GDAT etc.
+  !> @param[in] filename Name of file to read.
+  !> @param[inout] ncerr Error code, 0 for success, netCDF error code
+  !> otherwise.
+  !>
+  !> @author Edward Hartnett  @date 1-Nov-2023
+  !>
+  SUBROUTINE W3IOPON_READ(IOTST, IMOD, filename, ncerr)
+    use netcdf
+    USE W3GDATMD, ONLY: NTH, NK, NSPEC, FILEXT
+    USE W3ODATMD, ONLY: NDST, NDSE, IPASS => IPASS2, NOPTS, IPTINT, &
+         IL, IW, II, PTLOC, PTIFAC, DPO, WAO, WDO,   &
+         ASO, CAO, CDO, SPCO, PTNME, O2INIT, FNMPRE, &
+         GRDID, ICEO, ICEHO, ICEFO
+#ifdef W3_FLX5
+    USE W3ODATMD, ONLY: TAUAO, TAUDO, DAIRO
+#endif
+#ifdef W3_SETUP
+    USE W3ODATMD, ONLY: ZET_SETO
+#endif
+    IMPLICIT NONE
+
+    INTEGER, INTENT(OUT)          :: IOTST
+    INTEGER, INTENT(IN), OPTIONAL :: IMOD
+    character(*), intent(in) :: filename
+    integer, intent(inout) :: ncerr
+    integer :: fh
+    integer :: d_nopts, d_nspec, d_vsize, d_namelen, d_grdidlen    
+    integer :: d_nopts_len, d_nspec_len, d_vsize_len, d_namelen_len, d_grdidlen_len    
+    integer :: v_idtst, v_vertst, v_nk, v_mth, v_ptloc, v_ptnme
+    integer :: v_iw, v_ii, v_il, v_dpo, v_wao, v_wdo, v_tauao
+    integer :: v_taido, v_dairo, v_zet_seto, v_aso, v_cao, v_cdo, v_iceo
+    integer :: v_iceho, v_icefo, v_grdid, v_spco
+
+    print *,filename
+    IOTST = 0
+    
+    ! Open the netCDF file.
+    ncerr = nf90_open(filename, NF90_NOWRITE, fh)
+    if (ncerr .ne. 0) return
+
+    ! Read the dimension information for NOPTS.
+    ncerr = nf90_inq_dimid(fh, DNAME_NOPTS, d_nopts)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inquire_dimension(fh, d_nopts, len = d_nopts_len)
+    if (ncerr .ne. 0) return
+
+    ! Read the dimension information for NSPEC.
+    ncerr = nf90_inq_dimid(fh, DNAME_NSPEC, d_nspec)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inquire_dimension(fh, d_nspec, len = d_nspec_len)
+    if (ncerr .ne. 0) return
+
+    ! Read the dimension information for VSIZE.
+    ncerr = nf90_inq_dimid(fh, DNAME_VSIZE, d_vsize)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inquire_dimension(fh, d_vsize, len = d_vsize_len)
+    if (ncerr .ne. 0) return
+
+    ! Read the dimension information for NAMELEN.
+    ncerr = nf90_inq_dimid(fh, DNAME_NAMELEN, d_namelen)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inquire_dimension(fh, d_namelen, len = d_namelen_len)
+    if (ncerr .ne. 0) return
+
+    ! Read the dimension information for GRDIDLEN.
+    ncerr = nf90_inq_dimid(fh, DNAME_GRDIDLEN, d_grdidlen)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inquire_dimension(fh, d_grdidlen, len = d_grdidlen_len)
+    if (ncerr .ne. 0) return
+
+    ! Read scalar variables.
+    ncerr = nf90_inq_varid(fh, VNAME_NK, v_nk)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_nk, NK)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_MTH, v_mth)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_mth, NTH)
+    if (ncerr .ne. 0) return
+
+    ! Read vars with nopts as a dimension.
+    ncerr = nf90_inq_varid(fh, VNAME_PTLOC, v_ptloc)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_ptloc, PTLOC)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_PTNME, v_ptnme)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_ptnme, PTNME)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_IW, v_iw)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_iw, IW)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_II, v_ii)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_ii, II)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_IL, v_il)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_il, IL)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_DPO, v_dpo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_dpo, DPO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_WAO, v_wao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_wao, WAO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_WDO, v_wdo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_wdo, WDO)
+    if (ncerr .ne. 0) return
+#ifdef W3_FLX5
+    ncerr = nf90_inq_varid(fh, VNAME_TAUAO, v_tauao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_tauao, TAUAO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_TAIDO, v_taido)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_taido, TAIDO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_DAIRO, v_dairo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_dairo, DAIRO)
+    if (ncerr .ne. 0) return
+#endif    
+#ifdef W3_SETUP
+    ncerr = nf90_inq_varid(fh, ZET_SETO, v_zet_seto)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_zet_seto, ZET_SETO)
+    if (ncerr .ne. 0) return
+#endif    
+    ncerr = nf90_inq_varid(fh, VNAME_ASO, v_aso)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_aso, ASO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_CAO, v_cao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_cao, CAO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_CDO, v_cdo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_cdo, CDO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_ICEO, v_iceo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_iceo, ICEO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_ICEHO, v_iceho)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_iceho, ICEHO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_ICEFO, v_icefo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_icefo, ICEFO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_GRDID, v_grdid)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_grdid, GRDID)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_inq_varid(fh, VNAME_SPCO, v_spco)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_get_var(fh, v_spco, SPCO)
+    if (ncerr .ne. 0) return
+    
+    ! Close the file.
+    ncerr = nf90_close(fh)
+    if (ncerr .ne. 0) return
+    
+  END SUBROUTINE W3IOPON_READ
+
+  !/ ------------------------------------------------------------------- /
+  !>
+  !> @brief Write point output in netCDF format.
+  !>
+  !> @param[in] IMOD Model number for W3GDAT etc.
+  !> @param[in] filename Name of file to write.
+  !> @param[in] timestep_only Will be 0 if whole model run should be
+  !> written, 1 if only one timestep should be written.
+  !> @param[inout] ncerr Error code, 0 for success, netCDF error code
+  !> otherwise.
+  !>
+  !> @author Edward Hartnett  @date 1-Nov-2023
+  !>
+  SUBROUTINE W3IOPON_WRITE(timestep_only, IMOD, filename, ncerr)
+    use netcdf
+    USE W3GDATMD, ONLY: NTH, NK, NSPEC, FILEXT
+    USE W3ODATMD, ONLY: NDST, NDSE, IPASS => IPASS2, NOPTS, IPTINT, &
+         IL, IW, II, PTLOC, PTIFAC, DPO, WAO, WDO,   &
+         ASO, CAO, CDO, SPCO, PTNME, O2INIT, FNMPRE, &
+         GRDID, ICEO, ICEHO, ICEFO
+#ifdef W3_FLX5
+    USE W3ODATMD, ONLY: TAUAO, TAUDO, DAIRO
+#endif
+#ifdef W3_SETUP
+    USE W3ODATMD, ONLY: ZET_SETO
+#endif
+    
+    IMPLICIT NONE
+    integer, intent(in) :: timestep_only ! 1 if only timestep should be written.
+    INTEGER, INTENT(IN) :: IMOD
+    character(*), intent(in) :: filename
+    integer, intent(inout) :: ncerr
+    integer :: fh, ndim, nvar, fmt
+    integer :: d_nopts, d_nspec, d_vsize, d_namelen, d_grdidlen
+    integer :: v_idtst, v_vertst, v_nk, v_mth, v_ptloc, v_ptnme
+    integer :: v_iw, v_ii, v_il, v_dpo, v_wao, v_wdo, v_tauao
+    integer :: v_taido, v_dairo, v_zet_seto, v_aso, v_cao, v_cdo, v_iceo
+    integer :: v_iceho, v_icefo, v_grdid, v_spco
+    character (len = *), parameter :: FILE_NAME = "f90tst_nc4.nc"
+    CHARACTER(LEN=31), PARAMETER :: IDSTR = 'WAVEWATCH III POINT OUTPUT FILE'
+    CHARACTER(LEN=10), PARAMETER :: VEROPT = '2021-04-06'
+
+    print *, 'WRITE ',filename, len(filename)
+
+    ! Create the netCDF file.
+    ncerr = nf90_create(filename, NF90_NETCDF4, fh)
+    if (ncerr .ne. 0) return
+
+    ! Define dimensions.
+    ncerr = nf90_def_dim(fh, DNAME_NOPTS, NOPTS, d_nopts)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_dim(fh, DNAME_NSPEC, NSPEC, d_nspec)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_dim(fh, DNAME_VSIZE, 2, d_vsize)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_dim(fh, DNAME_NAMELEN, 40, d_namelen)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_dim(fh, DNAME_GRDIDLEN, 13, d_grdidlen)
+    if (ncerr .ne. 0) return
+
+    ! Define global attributes.
+    ncerr = nf90_put_att(fh, NF90_GLOBAL, 'title', IDSTR)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_att(fh, NF90_GLOBAL, 'version', VEROPT)
+    if (ncerr .ne. 0) return
+    
+    ! Define scalar variables.
+    ncerr = nf90_def_var(fh, VNAME_NK, NF90_INT, v_nk)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_MTH, NF90_INT, v_mth)
+    if (ncerr .ne. 0) return
+
+    ! Define vars with nopts as a dimension.
+    ncerr = nf90_def_var(fh, VNAME_PTLOC, NF90_INT, (/d_vsize, d_nopts/), v_ptloc)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_PTNME, NF90_CHAR, (/d_namelen, d_nopts/), v_ptnme)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_IW, NF90_INT, (/d_nopts/), v_iw)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_II, NF90_INT, (/d_nopts/), v_ii)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_IL, NF90_INT, (/d_nopts/), v_il)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_DPO, NF90_INT, (/d_nopts/), v_dpo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_WAO, NF90_INT, (/d_nopts/), v_wao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_WDO, NF90_INT, (/d_nopts/), v_wdo)
+    if (ncerr .ne. 0) return
+#ifdef W3_FLX5
+    ncerr = nf90_def_var(fh, VNAME_TAUAO, NF90_INT, (/d_nopts/), v_tauao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_TAIDO, NF90_INT, (/d_nopts/), v_taido)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_DAIRO, NF90_INT, (/d_nopts/), v_dairo)
+    if (ncerr .ne. 0) return
+#endif    
+#ifdef W3_SETUP
+    ncerr = nf90_def_var(fh, VNAME_ZET_SETO, NF90_INT, (/d_nopts/), v_zet_seto)
+    if (ncerr .ne. 0) return
+#endif    
+    ncerr = nf90_def_var(fh, VNAME_ASO, NF90_INT, (/d_nopts/), v_aso)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_CAO, NF90_INT, (/d_nopts/), v_cao)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_CDO, NF90_INT, (/d_nopts/), v_cdo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_ICEO, NF90_INT, (/d_nopts/), v_iceo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_ICEHO, NF90_INT, (/d_nopts/), v_iceho)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_ICEFO, NF90_INT, (/d_nopts/), v_icefo)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_GRDID, NF90_CHAR, (/d_grdidlen, d_nopts/), v_grdid)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_def_var(fh, VNAME_SPCO, NF90_INT, (/d_nspec, d_nopts/), v_spco)
+    if (ncerr .ne. 0) return
+
+    ! Write the scalar data.
+    ncerr = nf90_put_var(fh, v_nk, NK)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_mth, NTH)
+    if (ncerr .ne. 0) return
+
+    ! Write the data with NOPTS as a dimension.
+    ncerr = nf90_put_var(fh, v_ptloc, PTLOC)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_ptnme, PTNME)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_iw, IW)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_ii, II)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_il, IL)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_dpo, DPO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_wao, WAO)
+    if (ncerr .ne. 0) return
+#ifdef W3_FLX5
+    ncerr = nf90_put_var(fh, v_tauao, TAUAO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_taido, TAIDO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_dairo, DAIRO)
+    if (ncerr .ne. 0) return
+#endif
+#ifdef W3_SETUP
+    ncerr = nf90_put_var(fh, v_zet_seto, ZET_SETO)
+    if (ncerr .ne. 0) return
+#endif
+    ncerr = nf90_put_var(fh, v_aso, ASO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_cao, CAO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_iceo, ICEO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_iceho, ICEHO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_icefo, ICEFO)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_grdid, GRDID)
+    if (ncerr .ne. 0) return
+    ncerr = nf90_put_var(fh, v_spco, SPCO)
+    if (ncerr .ne. 0) return
+
+    ! Close the file.
+    ncerr = nf90_close(fh)
+    if (ncerr .ne. 0) return
+
+  END SUBROUTINE W3IOPON_WRITE
+
+  !> Read/write point output in netCDF format.
+  !>
+  !> @param[in] INXOUT String indicating read/write. Must be 'READ' or
+  !> 'WRITE'.
+  !> @param[in] NDSOP File unit number.
+  !> @param[out] IOTST Error code:
+  !> - 0 No error.
+  !> - -1 Unexpected end of file when reading.
+  !> @param[in] IMOD Model number for W3GDAT etc.
+#ifdef W3_ASCII
+  !> @param[in] NDSOA File unit number for ASCII output.
+#endif
+  !>
+  !> @author Edward Hartnett  @date 1-Nov-2023
+  SUBROUTINE W3IOPON ( INXOUT, NDSOP, IOTST, IMOD &
+#ifdef W3_ASCII
+      ,NDSOA &
+#endif
+      )
+    USE W3GDATMD, ONLY: W3SETG
+    USE W3WDATMD, ONLY: W3SETW
+    USE W3ODATMD, ONLY: W3SETO, W3DMO2
+    !/
+    USE W3GDATMD, ONLY: NTH, NK, NSPEC, FILEXT
+    USE W3WDATMD, ONLY: TIME
+    USE W3ODATMD, ONLY: NDST, NDSE, IPASS => IPASS2, NOPTS, IPTINT, &
+         IW, PTLOC, PTIFAC, WAO, WDO,   &
+         SPCO, PTNME, O2INIT, FNMPRE
+#ifdef W3_FLX5
+    USE W3ODATMD, ONLY: TAUAO, TAUDO, DAIRO
+#endif
+    USE W3ODATMD, ONLY :  OFILES
+    !/
+#ifdef W3_SETUP
+    USE W3ODATMD, ONLY: ZET_SETO
+#endif
+    !/
+    USE W3SERVMD, ONLY: EXTCDE
+#ifdef W3_S
+    USE W3SERVMD, ONLY: STRACE
+#endif
+    use netcdf
+    IMPLICIT NONE
+
+    CHARACTER, INTENT(IN)         :: INXOUT*(*)
+    INTEGER, INTENT(IN)           :: NDSOP
+    INTEGER, INTENT(OUT)          :: IOTST
+    INTEGER, INTENT(IN), OPTIONAL :: IMOD
+#ifdef W3_ASCII
+    INTEGER, INTENT(IN), OPTIONAL :: NDSOA
+#endif
+
+    INTEGER :: IGRD, MK, MTH
+    character(len = 124) :: filename
+    integer :: ncerr
+
+    ! Optimistically assume success.
+    IOTST = 0
+
+    ! Has a model number been specified?
+    IF (PRESENT(IMOD)) THEN
+      IGRD = IMOD
+    ELSE
+      IGRD = 1
+    END IF
+
+    CALL W3SETO(IGRD, NDSE, NDST)
+    CALL W3SETG(IGRD, NDSE, NDST)
+    CALL W3SETW(IGRD, NDSE, NDST)
+
+    ! INXOUT must be 'READ' or 'WRITE'.
+    IF (INXOUT .NE. 'READ' .AND. INXOUT .NE. 'WRITE') THEN
+      WRITE (NDSE, 900) INXOUT
+      CALL EXTCDE(1)
+   END IF
+
+   ! Determine filename.
+   filename = ''
+   filename = transfer(FNMPRE(:LEN_TRIM(FNMPRE))//'out_pnt_nc.'//FILEXT(:LEN_TRIM(FILEXT)), filename)
+   !print *, filename
+   
+   ! Do a read or a write of the point file.
+   IF (INXOUT .EQ. 'READ') THEN
+      CALL W3IOPON_READ(IOTST, IMOD, filename, ncerr)
+   ELSE
+      CALL W3IOPON_WRITE(OFILES(2), IMOD, filename, ncerr)
+   ENDIF
+   if (ncerr .ne. 0) then
+      print *, nf90_strerror(ncerr)
+      CALL EXTCDE(21)      
+   endif
+   
+    !/
+    !/ End of W3IOPON ----------------------------------------------------- /
+    !/
+
+900 FORMAT (/' *** WAVEWATCH III ERROR IN W3IOPO :'/                &
+         '     ILEGAL INXOUT VALUE: ',A/)
+  END SUBROUTINE W3IOPON
+  !/ ------------------------------------------------------------------- /
   !> Read or write point output.
   !>
   !> This subroutine can either read or write the point output file,
@@ -1495,7 +2052,7 @@ SUBROUTINE W3IOPO ( INXOUT, NDSOP, IOTST, IMOD &
 #endif
              'ASO(I), CAO(I), CDO(I), ICEO(I), ICEHO(I):',        &
              ASO(I), CAO(I), CDO(I), ICEO(I), ICEHO(I),        &
-             'ICEFO(I), GRDID(I), (SPCO(J,I),J=1,NSPEC):',       & 
+             'ICEFO(I), GRDID(I), (SPCO(J,I),J=1,NSPEC):',       &
              ICEFO(I), GRDID(I), (SPCO(J,I),J=1,NSPEC)
 #endif
       ELSE
diff --git a/model/tests/CMakeLists.txt b/model/tests/CMakeLists.txt
new file mode 100644
index 000000000..97717233b
--- /dev/null
+++ b/model/tests/CMakeLists.txt
@@ -0,0 +1,40 @@
+# This is the CMake file for the model/tests directory in the WW3
+# project. 
+#
+# Ed Hartnett, 10/14/23
+
+# Some very small test files may be committed to the repo. This
+# function copies such a data file to the build directory.
+function(copy_test_data name)
+  file(COPY "${CMAKE_CURRENT_SOURCE_DIR}/data/${name}"
+    DESTINATION ${CMAKE_CURRENT_BINARY_DIR}
+    FILE_PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ)
+endfunction()
+
+# Some very small test files may be committed to the repo. This
+# function copies such a data file to the build directory.
+function(copy_test_data_2 srcname destname)
+  file(COPY "${CMAKE_CURRENT_SOURCE_DIR}/data/${srcname}"
+    DESTINATION "${CMAKE_CURRENT_BINARY_DIR}"
+    FILE_PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ)
+  file(RENAME "${CMAKE_CURRENT_BINARY_DIR}/${srcname}" "${CMAKE_CURRENT_BINARY_DIR}/${destname}")
+endfunction()
+
+# Function to build and run a test.
+function(unit_test name)
+  add_executable(${name} ${name}.F90)
+  target_link_libraries(${name} PRIVATE ww3_lib)
+  add_test(NAME ${name} COMMAND ${name})
+endfunction()
+
+# Copy test data files that are in the repo to the build directory.
+copy_test_data(out_pnt.ww3)
+copy_test_data_2(io_mod_def.ww3 mod_def.ww3)
+copy_test_data(switch.io)
+copy_test_data(ww3_outp.inp)
+
+# Build and run the tests.
+unit_test(test_io_points_bin)
+unit_test(test_io)
+
+
diff --git a/model/tests/data/io_mod_def.ww3 b/model/tests/data/io_mod_def.ww3
new file mode 100644
index 000000000..b8d754881
Binary files /dev/null and b/model/tests/data/io_mod_def.ww3 differ
diff --git a/model/tests/data/out_pnt.points b/model/tests/data/out_pnt.points
new file mode 100644
index 000000000..a85412a73
Binary files /dev/null and b/model/tests/data/out_pnt.points differ
diff --git a/model/tests/data/out_pnt.ww3 b/model/tests/data/out_pnt.ww3
new file mode 100644
index 000000000..a911732ac
Binary files /dev/null and b/model/tests/data/out_pnt.ww3 differ
diff --git a/model/tests/data/switch.io b/model/tests/data/switch.io
new file mode 100644
index 000000000..c97e44765
--- /dev/null
+++ b/model/tests/data/switch.io
@@ -0,0 +1 @@
+NOGRB SHRD PR1 FLX2 LN0 ST0 NL0 BT0 DB0 TR0 BS0 IC0 IS0 REF0 WNT1 WNX1 CRT1 CRX1 O0 O1 O2 O3 O4 O5 O6 O7 O10 O11
\ No newline at end of file
diff --git a/model/tests/data/ww3_outp.inp b/model/tests/data/ww3_outp.inp
new file mode 100644
index 000000000..dd728819f
--- /dev/null
+++ b/model/tests/data/ww3_outp.inp
@@ -0,0 +1,8 @@
+$
+ 20100101 000000 3600 1
+$
+ 1
+ -1
+$
+ 4
+ 2 30 20100101 000000 'UTC'
diff --git a/model/tests/test_io.F90 b/model/tests/test_io.F90
new file mode 100644
index 000000000..7ae39f3f8
--- /dev/null
+++ b/model/tests/test_io.F90
@@ -0,0 +1,99 @@
+! This is a test for model IO for WW3.
+!
+! Ed Hartnett 10/14/23
+program test_io
+  use w3iopomd
+  use w3gdatmd
+  use w3wdatmd
+  use w3odatmd
+  use w3iogrmd
+  use w3adatmd  
+  implicit none
+  
+  integer, target :: i, j, k, l
+  integer :: ndsop, iotest, imod, ndstst, ierr, ndsbul, ndsm
+  integer :: ndstrc, ntrace
+  real :: m2km
+  character*7 expected_ptnme
+  character*6 my_fmt
+  real :: expected_loc_1
+
+  print *, 'Testing WW3 binary point file code.'
+
+  ! These are mysterious but have to be called or else the IPASS
+  ! variable does not exist and w3iopo() crashes.
+  call w3nmod(1, 6, 6)
+  call w3setg(1, 6, 6)
+  call w3ndat(6, 6)
+  call w3setw(1, 6, 6)
+  call w3nout(6, 6)
+  call w3seto(1, 6, 6)
+
+  ndsm   = 20
+  ndsop  = 20
+  ndsbul = 0
+  ndstrc =  6
+  ntrace = 10
+
+  write (ndso,900)
+900 FORMAT (/15X,'    *** WAVEWATCH III Point output post.***    '/ &
+       15X,'==============================================='/)
+
+  ! Open the file with the output settings for WW3. It is not needed actually.
+  ! open(ndsi, file = 'ww3_outp.inp', status='old', iostat = ierr)
+  ! if (ierr .ne. 0) stop 10
+
+  ! 2.  Read model definition file.
+  CALL W3IOGR('READ', NDSM)
+  WRITE (NDSO,920) GNAME
+920 FORMAT ('  Grid name : ',A/)  
+
+  ! IF (FLAGLL) THEN
+  !   M2KM = 1.
+  ! ELSE
+  !   M2KM = 1.E-3
+  ! END IF
+
+  ! Read the file out_pnt.ww3 from the model/tests/data directory.
+  call w3iopo('READ', ndsop, iotest)
+  if (iotest .ne. 0) stop 10
+  close(ndsop)
+
+  ! Make sure we got the values we expected.
+  if (nopts .ne. 11) stop 11
+  expected_loc_1 = 0.0
+  do i = 1, nopts
+     ! Check ptnme and ptloc arrays.
+     print *, ptnme(i), ptloc(1, i), ptloc(2, i)
+     if (i .lt. 10) then
+        my_fmt = '(a,i1)'
+     else
+        my_fmt = '(a,i2)'
+     endif
+     write(fmt = my_fmt, unit=expected_ptnme) 'Point', i
+     if (ptnme(i) .ne. expected_ptnme) stop 20
+     print *, expected_loc_1
+     if (ptloc(1, i) .ne. expected_loc_1) stop 21
+     expected_loc_1 = expected_loc_1 + 5000.0
+     if (ptloc(2, i) .ne. 0) stop 22
+  end do
+  
+  print *, 'OK!'
+  print *, 'testing writing the WW3 binary point file in netCDF...'
+
+  ! Write in netCDF.
+  call w3iopon('WRITE', ndsop, iotest)
+  if (iotest .ne. 0) stop 100
+  print *, 'OK!'
+  
+  print *, 'testing reading the WW3 binary point file in netCDF...'
+  call w3iopon('READ', ndsop, iotest)
+  print *, iotest
+  if (iotest .ne. 0) stop 100
+  print *, 'OK!'
+  
+  print *, 'OK!'
+  
+  print *, 'SUCCESS!'
+end program test_io
+  
diff --git a/model/tests/test_io_points_bin.F90 b/model/tests/test_io_points_bin.F90
new file mode 100644
index 000000000..8bc0e5b75
--- /dev/null
+++ b/model/tests/test_io_points_bin.F90
@@ -0,0 +1,83 @@
+! This is a test for model IO for WW3. This tests the legacy (binary)
+! output of points data, done by function W3IOPO().
+!
+! Ed Hartnett 10/14/23
+program test_io_points_bin
+  use w3iopomd
+  use w3gdatmd
+  use w3wdatmd
+  use w3odatmd
+  use w3iogrmd
+  use w3adatmd  
+  implicit none
+  
+  integer, target :: i, j, k, l
+  integer :: ndsop, iotest, imod, ndstst, ierr, ndsbul, ndsm
+  integer :: ndstrc, ntrace
+  real :: m2km
+  character*7 expected_ptnme
+  character*6 my_fmt
+  real :: expected_loc_1
+
+  print *, 'Testing WW3 binary point file code.'
+
+  ! These are mysterious but have to be called or else the IPASS
+  ! variable does not exist and w3iopo() crashes.
+  call w3nmod(1, 6, 6)
+  call w3setg(1, 6, 6)
+  call w3ndat(6, 6)
+  call w3setw(1, 6, 6)
+  call w3nout(6, 6)
+  call w3seto(1, 6, 6)
+
+  ndsm   = 20
+  ndsop  = 20
+  ndsbul = 0
+  ndstrc =  6
+  ntrace = 10
+
+  write (ndso,900)
+900 FORMAT (/15X,'    *** WAVEWATCH III Point output post.***    '/ &
+       15X,'==============================================='/)
+
+  ! Open the file with the output settings for WW3. It is not needed actually.
+  ! open(ndsi, file = 'ww3_outp.inp', status='old', iostat = ierr)
+  ! if (ierr .ne. 0) stop 10
+
+  ! 2.  Read model definition file.
+  CALL W3IOGR('READ', NDSM)
+  WRITE (NDSO,920) GNAME
+920 FORMAT ('  Grid name : ',A/)  
+
+  ! This will not work. But cannot be tested because it will change the value of IPASS,
+!  call w3iopo('EAD', ndsop, iotest)
+!  if (iotest .ne. 1) stop 7
+
+  ! Read the file out_pnt.ww3 from the model/tests/data directory.
+  call w3iopo('READ', ndsop, iotest)
+  if (iotest .ne. 0) stop 10
+  close(ndsop)
+
+  ! Make sure we got the values we expected.
+  if (nopts .ne. 11) stop 11
+  expected_loc_1 = 0.0
+  do i = 1, nopts
+     ! Check ptnme and ptloc arrays.
+     print *, ptnme(i), ptloc(1, i), ptloc(2, i)
+     if (i .lt. 10) then
+        my_fmt = '(a,i1)'
+     else
+        my_fmt = '(a,i2)'
+     endif
+     write(fmt = my_fmt, unit=expected_ptnme) 'Point', i
+     if (ptnme(i) .ne. expected_ptnme) stop 20
+     print *, expected_loc_1
+     if (ptloc(1, i) .ne. expected_loc_1) stop 21
+     expected_loc_1 = expected_loc_1 + 5000.0
+     if (ptloc(2, i) .ne. 0) stop 22
+  end do
+  
+  print *, 'OK!'
+  print *, 'SUCCESS!'
+end program test_io_points_bin
+