Addition of an example unit test for users to learn from

sorc/chgres_cube.fd/grib2_util.F90

@@ -17,18 +17,19 @@ module grib2_util
 
 implicit none
 
+public :: rh2spfh
+public :: convert_omega
 public :: rh2spfh_gfs
 public :: fpvsnew 
 
-
 contains 
 
 !> Convert relative humidity to specific humidity.
 !> Calculation of saturation water vapor pressure is based on
 !> Brock and Richardson 2001 (Meterological Measurement 
 !> Systems, p. 86, equation 5.1) 
 !!
-!! @param[inout] rh_sphum rel humidity on input. spec hum on output.
+!! @param[inout] rh_sphum rel humidity (%) on input. spec hum (kg/kg) on output.
 !! @param[in] p pressure in Pa
 !! @param[in] t temperature
 !! @author Larissa Reames
@@ -59,7 +60,7 @@ subroutine rh2spfh(rh_sphum,p,t)
   !print *, 'q = ', sphum
 
   !if (P .eq. 100000.0) THEN
-  ! print *, 'T = ', T, ' RH = ', RH, ' P = ', P, ' es = ', es, ' e = ', e, ' q = ', sphum
+  !print *, 'T = ', t, ' RH = ', rh, ' P = ', p, ' es = ', es, ' e = ', e, ' q = ', rh_sphum
   !end if
 
 end subroutine RH2SPFH

tests/README.md

@@ -1,7 +1,7 @@
 ## HOW TO CREATE A UNIT TEST.
 
 Unit tests should test only small parts of a program. For example,
-a single routine or function.
+a single routine or function, or multiple closely-linked routines.
 
 Source code for a test shall be placed in a program
 specific directory under ./tests.
@@ -86,6 +86,17 @@ To run the tests locally, invoke one of the following after the `make install`:
 For the parallel tests to run locally, update the machine-specific
 "mpi_exec" script under [cmake](../cmake) with your run account and queue.
 
+### EXAMPLE UNIT TEST:
+
+An example unit test, ftst_example.F90, exists in the tests/chgres_cube directory
+and is currently compiled and run with existing tests
+
+This simple test checks whether the routine rh2spfh in chgres_cube.fd/grib2_util.F90
+is working correctly, and contains detailed comments explaining what each section 
+of the test does. It also prompts the user to create additional lines of code to 
+test one more subroutine from grib2_util.F90. Use this to get started understanding
+the unit test framework.
+
 ### QUESTIONS
 
 Please contact the repository managers: https://github.com/NOAA-EMC/UFS_UTILS/wiki

tests/chgres_cube/CMakeLists.txt

@@ -199,3 +199,7 @@ add_mpi_test(chgres_cube-ftst_surface_search_many
 add_executable(ftst_read_vcoord ftst_read_vcoord.F90)
 target_link_libraries(ftst_read_vcoord chgres_cube_lib)
 add_test(NAME chgres_cube-ftst_read_vcoord COMMAND ftst_read_vcoord)
+
+add_executable(ftst_example ftst_example.F90)
+target_link_libraries(ftst_example chgres_cube_lib)
+add_test(NAME chgres_cube-ftst_example COMMAND ftst_example)

tests/chgres_cube/ftst_example.F90

@@ -0,0 +1,99 @@
+! Unit test for rh2spfh in grib2_utils to be used as an example for users
+! learning how to write unit tests. Users are prompted to add an additional
+! test for convert_omega
+! Larissa Reames OU/CIMMS/NOAA/NSSL/FRDD
+
+program ftst_example
+
+ use esmf
+ use model_grid, only : i_input, j_input 
+ use grib2_util, only : rh2spfh
+
+ implicit none
+
+ real(esmf_kind_r4), allocatable :: rh_spfh(:,:), &
+                                    rh_orig(:,:), &
+                                    spfh_returned(:,:), &
+                                    spfh_correct(:,:)
+ real(esmf_kind_r8),allocatable  :: t(:,:)
+ real(esmf_kind_r8) :: p
+ real,parameter          :: EPS = 1.0E-6
+
+ i_input = 2
+ j_input = 2
+ allocate(rh_spfh(i_input,j_input))
+ allocate(rh_orig(i_input,j_input))
+ allocate(spfh_returned(i_input,j_input))
+ allocate(spfh_correct(i_input,j_input))
+ allocate(t(i_input,j_input))
+
+ ! -------------------------------------------------------------------------
+ ! Set constants/values to be passed to the unit test. In this case it's a
+ ! set of single values, but it could be more complicated, like an 
+ ! n-dimensional array or ESMF objects.
+ ! -------------------------------------------------------------------------
+
+ rh_spfh(:,:) = 50.0  ! Relative humidity (%)
+ p = 100000.0    ! Pressure (Pa)
+ t(:,:) = 300.0       ! Temperature (K)
+ spfh_correct(:,:) = 10.978297E-3 ! Correct specific humidity value (kg/kg)
+
+ print*, "Starting Unit Testing rh2spfh."
+
+ !-------------------------------------------------------------------------
+ ! Execute testing below by running target function rh2spfh and providing
+ ! values set above
+ !-------------------------------------------------------------------------
+
+ rh_orig = rh_spfh          ! Save the original RH value for posterity
+ call rh2spfh(rh_spfh,p,t) 
+ spfh_returned = rh_spfh    ! Rename the returned value for clarity
+
+ !-------------------------------------------------------------------------
+ ! Check the returned value against what we know to be the correct answer. 
+ ! If the correct result is returned (within a certain small tolerance), 
+ ! then the test passes and the called routine is working as expected. If the 
+ ! incorrect value is passed back, the test fails and an error is returned.
+ !-------------------------------------------------------------------------
+
+ if ( any(abs(spfh_returned - spfh_correct) .gt. EPS)) then 
+   stop 1
+   print*, "RH2SPFH TEST FAILED."
+ endif
+
+ !-------------------------------------------------------------------------
+ ! If you are trying to debug a test failure, code like the commented
+ ! section below might prove useful.
+ !-------------------------------------------------------------------------
+
+ ! if ( any(abs(spfh_returned - spfh_correct) .lt. EPS)) then
+ !   print*, "RH2SPFH TEST PASSED. SUCCESS!"
+ ! else
+ !   print*, "RH2SPFH TEST FAILED."
+ !   print*, "TEST RETURNED VALUE OF ", spfh_returned
+ !   print*, "RETURNED VALUE EXPECT TO BE ", spfh_correct
+ !   stop 1
+ ! endif
+
+ !-------------------------------------------------------------------------
+ ! Make sure to deallocate any and all allocatable arrays that you use
+ !-------------------------------------------------------------------------
+
+ deallocate(rh_spfh,spfh_correct,rh_orig,spfh_returned,t)
+
+ ! -------------------------------------------------------------------------
+ ! You can test multiple subroutines (units) in any test file. This would
+ ! be a good place to test the other subroutine in grib2_util, 
+ ! convert_omega. Make note of the difference in variable size for this 
+ ! routine. You don't have to pass an array of size you'd normally 
+ ! encounter for these variables (like 200x200x64), just choose a small
+ ! size with the proper dimensionality, say 3x3x2, and fill it with values
+ ! typical of the various arrays. You can check the returned array element-
+ ! by-element, or use the any() command to check all elements at once. Make
+ ! sure to provide a helpful failure message indicating where the failure 
+ ! occured and what the returned/expected values were at that location. Also,
+ ! don't forget to deallocate any allocatable arrays as this will cause a
+ ! failure when compiling the test with gnu compilers and address sanitizers.
+ ! -------------------------------------------------------------------------
+
+end program ftst_example