diff --git a/src/w3fi73.f b/src/w3fi73.f
index a9093c5c..e6895a64 100644
--- a/src/w3fi73.f
+++ b/src/w3fi73.f
@@ -12,11 +12,11 @@
 C> @param[in] IBFLAG
 C> - 0, if bit map supplied by user
 C> - #, Number of predefined center bit map
-C> @param[in] IBMAP Integer array containing user bit map
-C> @param[in] IBLEN Length of bit map
-C> @param[out] BMS Completed grib bit map section
-C> @param[out] LENBMS Length of bit map section
-C> @param[out] IER 0 normal exit, 8 = ibmap values are all zero
+C> @param[in] IBMAP Integer array containing user bit map.
+C> @param[in] IBLEN Length of bit map.
+C> @param[out] BMS Completed grib bit map section.
+C> @param[out] LENBMS Length of bit map section in bytes.
+C> @param[out] IER 0 normal exit, 8 = ibmap values are all zero.
 C>
 C> @author M. Farley @date 1992-07-01
       SUBROUTINE W3FI73 (IBFLAG,IBMAP,IBLEN,BMS,LENBMS,IER)
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 7186e606..386fd6e5 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -16,7 +16,10 @@ endfunction()
 # These are the tests.
 foreach(kind ${kinds})
   create_test(test_summary ${kind})
+  create_test(test_gbytec ${kind})
   create_test(test_w3tagb ${kind})
   create_test(test_w3fi71 ${kind})
+#  create_test(test_w3fi72 ${kind})
+  create_test(test_w3fi73 ${kind})
   create_test(test_w3fi74 ${kind})
 endforeach()  
diff --git a/tests/test_gbytec.F90 b/tests/test_gbytec.F90
new file mode 100644
index 00000000..b4f669f3
--- /dev/null
+++ b/tests/test_gbytec.F90
@@ -0,0 +1,186 @@
+! This is a test program for the NCEPLIBS-w3emc project.
+!
+! This program tests the sbyte subroutines. The sbyte code is a
+! duplicate of code in the NCEPLIBS-g2 project, and this test was
+! developed for the NCEPLIBS-g2 project, and ported to NCEPLIBS-w3emc.
+!
+! See https://github.com/NOAA-EMC/NCEPLIBS-g2/issues/568 and
+! https://github.com/NOAA-EMC/NCEPLIBS-w3emc/issues/202.
+!
+! Ed Hartnett, 9/27/23
+program test_gbytec
+  implicit none
+
+  character*1 :: out(1)
+  character*1 :: out4(4)
+  character*1 :: out5(5)
+  character*1 :: out8(8)
+  character*1 :: out10(10)
+  integer, parameter :: n = 1
+  integer :: in(n)
+  real :: r_in(n)
+  integer, parameter :: n2 = 2
+  integer :: in2(n2)
+  real :: r_in2(n2)
+  integer, parameter :: n5 = 5
+  integer :: in5(n5)
+  integer :: iskip = 0
+  integer :: nbits = 8
+  integer :: nskip = 0
+  integer :: i
+  integer :: num
+  
+  print *, 'Testing sbyte subroutines.'
+
+  print *, 'Testing sbytec()...'
+  in(1) = 3
+  out(1) = char(0)
+  call sbytec(out, in, iskip, nbits)
+  if (ichar(out(1)) .ne. in(1)) stop 10
+
+  print *, 'Testing sbytesc()...'
+  in(1) = 3
+  out(1) = char(0)
+  call sbytesc(out, in, iskip, nbits, nskip, n)
+  if (ichar(out(1)) .ne. in(1)) stop 20
+
+  ! THIS will pack the numbers 1 and 2 into the first two chars of the
+  ! buffer. The rest of the output buffer will remain zeros.
+  print *, 'Testing g2_sbytesc() packing 2 values...'
+  in2(1) = 1
+  in2(2) = 2
+  do i = 1, 8
+     out8(i) = char(0)
+  end do
+  nbits = 8
+  call sbytesc(out8, in2, iskip, nbits, nskip, n2)
+  do i = 1, 8
+     if (i .le. 2) then
+        if (ichar(out8(i)) .ne. in2(i)) stop 30;
+     else
+        if (ichar(out8(i)) .ne. 0) stop 31;
+     endif
+  end do
+
+  ! Now pack 5 values into the 5 character array out5.
+  print *, 'Testing g2_sbytesc() packing 5 values...'
+  in5(1) = 1
+  in5(2) = 2
+  in5(3) = 3
+  in5(4) = 4
+  in5(5) = 5
+  nbits = 8
+  nskip = 0
+  do i = 1, 5
+     out5(i) = char(0)
+  end do
+  call sbytesc(out5, in5, iskip, nbits, nskip, n5)
+  do i = 1, 5
+     if (ichar(out5(i)) .ne. in5(i)) stop 40;     
+  end do
+
+  ! Now pack 5 values into the 10 character array out10. Skip every
+  ! other byte in the output.
+  print *, 'Testing g2_sbytesc() packing 5 values, skipping every other byte...'
+  nbits = 8
+  nskip = 0
+  do i = 1, 10
+     out10(i) = char(0)
+  end do
+  call sbytesc(out10, in5, iskip, nbits, 8, 5)
+  do i = 1, 10
+     ! print '(z2.2)', out10(i)
+     if (mod(i, 2) .gt. 0) then
+        if (ichar(out10(i)) .ne. in5(int(i/2) + 1)) stop 51;
+     else
+        if (ichar(out10(i)) .ne. 0) stop 50;
+     endif
+  end do
+
+  print *, 'Testing sbytec() with iskip of 1...'
+  in(1) = 1
+  out(1) = char(0)
+  call sbytec(out, in, 1, 6)
+  ! print '(z2.2)', out(1)  
+  if (ichar(out(1)) .ne. 2) stop 20
+
+  print *, 'Testing g2_sbytesc() with a small array...'
+  iskip = 0
+  nbits = 32
+  nskip = 0
+  num = 1
+  in(1) = 1
+  call sbytesc(out4, in, iskip, nbits, nskip, num)
+  if (ichar(out4(1)) .ne. 0 .and. ichar(out4(2)) .ne. 0 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 1) stop 50
+  !print '(z2.2)', out4(1)  
+
+  ! For this test to pass the -fallow-argument-mismatch flag must be
+  ! used, because I am passing in a real array instead of an int array
+  ! for the in parameter. This is how g2_sbytesc() is called in
+  ! addfield.F90.
+  print *, 'Testing sbytesc() with a real array (size 1) instead of an int array...'
+  iskip = 0
+  nbits = 32
+  nskip = 0
+  num = 1
+  r_in(1) = 1 
+  call sbytesc(out4, r_in, iskip, nbits, nskip, num)
+  ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
+  ! decimal for 3f is 63, the decimal for 80 is 128.
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
+  ! print '(z2.2)', out4(1)  
+  ! print '(z2.2)', out4(2)  
+  ! print '(z2.2)', out4(3)  
+  ! print '(z2.2)', out4(4)
+
+  ! This test is the same as above, but does not require the -fallow-argument-mismatch flag.
+  print *, 'Testing g2_sbytesc() with a real array (size 1) instead of an int array, using transfer() intrinsic...'
+  iskip = 0
+  nbits = 32
+  nskip = 0
+  num = 1
+  r_in(1) = 1
+  in = transfer(r_in, in)
+  call sbytesc(out4, in, iskip, nbits, nskip, num)
+  ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
+  ! decimal for 3f is 63, the decimal for 80 is 128.
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
+  ! print '(z2.2)', out4(1)  
+
+  ! For this test to pass the -fallow-argument-mismatch flag must be
+  ! used, because I am passing in a real array instead of an int array
+  ! for the in parameter. This is how g2_sbytesc() is called in
+  ! addfield.F90.
+  print *, 'Testing sbytesc() with a real array instead of an int array...'
+  iskip = 0
+  nbits = 32
+  nskip = 0
+  num = 2
+  r_in2(1) = 1 
+  r_in2(2) = 1 
+  call sbytesc(out8, r_in2, iskip, nbits, nskip, num)
+  ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
+  ! decimal for 3f is 63, the decimal for 80 is 128.
+  if (ichar(out8(1)) .ne. 63 .and. ichar(out8(2)) .ne. 128 .and. ichar(out8(3)) .ne. 0 .and. ichar(out8(4)) .ne. 0) stop 50
+  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 50
+  ! print '(z2.2)', out8(1)  
+
+  ! This test is the same as above, but does not require the -fallow-argument-mismatch flag.
+  print *, 'Testing sbytesc() with a real array instead of an int array, using transfer() intrinsic...'
+  iskip = 0
+  nbits = 32
+  nskip = 0
+  num = 2
+  r_in2(1) = 1 
+  r_in2(2) = 1 
+  in = transfer(r_in2, in2)
+  call sbytesc(out8, in2, iskip, nbits, nskip, num)
+  ! Note that the 32-bit IEEE representation of 1.0 is 3f800000. The
+  ! decimal for 3f is 63, the decimal for 80 is 128.
+  if (ichar(out4(1)) .ne. 63 .and. ichar(out4(2)) .ne. 128 .and. ichar(out4(3)) .ne. 0 .and. ichar(out4(4)) .ne. 0) stop 50
+  if (ichar(out8(5)) .ne. 63 .and. ichar(out8(6)) .ne. 128 .and. ichar(out8(7)) .ne. 0 .and. ichar(out8(8)) .ne. 0) stop 50
+  ! print '(z2.2)', out4(1)  
+
+  print *, 'SUCCESS!'
+
+end program test_gbytec
diff --git a/tests/test_w3fi72.F90 b/tests/test_w3fi72.F90
new file mode 100644
index 00000000..a5571a4f
--- /dev/null
+++ b/tests/test_w3fi72.F90
@@ -0,0 +1,55 @@
+! This is a test in the NCEPLIBS-w3emc project.
+!
+! Test the w3fi72() function.
+!
+! Ed Hartnett, 2/28/23
+program test_w3fi72
+  implicit none
+  integer :: i, iret
+  integer :: kf, nbit
+  parameter(kf = 489900)
+  parameter(nbit = 8)
+  integer maxbit
+  parameter(maxbit=24)  
+  character pds(40000)
+  real, dimension(:), allocatable :: fld
+  character*1, dimension(:), allocatable :: grib
+  integer igflag, igrid
+  parameter (igflag = 0)
+  integer ibm(kf),ipds(200),igds(200),ibds(200)
+  integer kfo, lgrib, icomp
+  integer ierr
+
+  print *, "Testing w3fi72..."
+
+  allocate(fld(kf))
+  allocate(grib(1000+kf*12))
+
+  ! Fill up some test data.
+  do i = 1, 200
+     ipds(i) = 0
+  end do
+  do i = 1, kf
+     fld(i) = i / 2
+  end do
+
+  ! Fill the igds array. This call comes from test_w3fi71.F90.
+  icomp = 0
+  igrid = 172
+  call w3fi71(igrid, igds, ierr)
+  if (ierr .ne. 0) stop 1
+
+ ! This call comes from NCEPLIBS-grib_util cnvgrb, putbexn.F90.
+   call w3fi72(0, fld, 0, nbit, 1, ipds, pds,  &
+        igflag, igrid, igds, icomp, 0, ibm, kf, ibds,  &
+        kfo, grib, lgrib, iret)
+   print *, kfo, lgrib, iret
+   if (kfo .ne. 489900) stop 2
+!   if (lgrib .ne. 489956) stop 3
+   if (iret .ne. 0) stop 4
+
+  deallocate(fld)
+  deallocate(grib)
+
+  print *, "SUCCESS"
+end program test_w3fi72
diff --git a/tests/test_w3fi73.F90 b/tests/test_w3fi73.F90
new file mode 100644
index 00000000..93aedd7a
--- /dev/null
+++ b/tests/test_w3fi73.F90
@@ -0,0 +1,39 @@
+! This is a test in the NCEPLIBS-w3emc project.
+!
+! Test the w3fi73() subroutine.
+!
+! Ed Hartnett, 9/27/23
+program test_w3fi73
+  implicit none
+  integer :: ibflag, iblen, lenbms
+  integer :: BLEN, BMSLEN
+  parameter (BLEN = 3)
+  parameter (BMSLEN = 3)
+  integer :: ibmap(BLEN), bms(BMSLEN)
+  integer :: i
+  integer :: ierr
+
+  print*,"Testing w3fi73..."
+
+  ! Return error code 8 if all ibmap values are 0.
+  ibflag = 0
+  do i = 1, BLEN
+     ibmap(i) = 0
+  end do
+  iblen = BLEN
+  call w3fi73(ibflag, ibmap, iblen, bms, lenbms, ierr)
+  if (ierr .ne. 8) stop 2
+
+  ! Return error code 8 if all ibmap values are 0.
+  ibflag = 0
+  do i = 1, BLEN
+     ibmap(i) = 1
+  end do
+  iblen = BLEN
+  call w3fi73(ibflag, ibmap, iblen, bms, lenbms, ierr)
+  if (ierr .ne. 0) stop 4
+  if (lenbms .ne. 8) stop 5
+!  if (bms(1) .ne. 218628096 .or. bms(2) .ne. 14680064) stop 7
+
+  print*,"SUCCESS"
+end program test_w3fi73
diff --git a/tests/test_w3fi74.F90 b/tests/test_w3fi74.F90
index 37ac14b9..266a5aef 100644
--- a/tests/test_w3fi74.F90
+++ b/tests/test_w3fi74.F90
@@ -31,7 +31,6 @@ program test_w3fi74
 
   ! Fill the igds array. This call comes from w3if72.f.
   icomp = 0
-  npts = 4
   call w3fi74(igds, icomp, gds, lengds, npts, ierr)
   if (ierr .ne. 0) stop 1
   if (lengds .ne. 32 .or. npts .ne. 489900) stop 2