diff --git a/tests/ncint/tst_var_compress.c b/tests/ncint/tst_var_compress.c
index 2db2761d1de..f7fd811e4cd 100644
--- a/tests/ncint/tst_var_compress.c
+++ b/tests/ncint/tst_var_compress.c
@@ -21,11 +21,75 @@
 #define NDIM3 3
 #define TEST_VAL_42 42
 
-extern NC_Dispatch NCINT_dispatcher;
+int
+run_var_compress_test(int my_rank, int ntasks, int iosysid)
+{
+    int ncid, ioid;
+    int dimid[NDIM3], varid;
+    int dimlen[NDIM3] = {NC_UNLIMITED, DIM_LEN_X, DIM_LEN_Y};
+    size_t elements_per_pe;
+    size_t *compdof; /* The decomposition mapping. */
+    int *my_data;
+    int *data_in;
+    int i;
+
+    /* Turn on logging for PIO library. */
+    /* PIOc_set_log_level(3); */
+
+    /* Create a file with a 3D record var. */
+    if (nc_create(FILE_NAME, NC_PIO, &ncid)) PERR;
+    if (nc_def_dim(ncid, DIM_NAME_UNLIMITED, dimlen[0], &dimid[0])) PERR;
+    if (nc_def_dim(ncid, DIM_NAME_X, dimlen[1], &dimid[1])) PERR;
+    if (nc_def_dim(ncid, DIM_NAME_Y, dimlen[2], &dimid[2])) PERR;
+    if (nc_def_var(ncid, VAR_NAME, NC_INT, NDIM3, dimid, &varid)) PERR;
+
+    /* Calculate a decomposition for distributed arrays. */
+    elements_per_pe = DIM_LEN_X * DIM_LEN_Y / ntasks;
+    if (!(compdof = malloc(elements_per_pe * sizeof(size_t))))
+	PERR;
+    for (i = 0; i < elements_per_pe; i++)
+	compdof[i] = my_rank * elements_per_pe + i;
+
+    /* Create the PIO decomposition for this test. */
+    if (nc_def_decomp(iosysid, PIO_INT, NDIM2, &dimlen[1], elements_per_pe,
+		      compdof, &ioid, 1, NULL, NULL)) PERR;
+    free(compdof);
+
+    /* Create some data on this processor. */
+    if (!(my_data = malloc(elements_per_pe * sizeof(int)))) PERR;
+    for (i = 0; i < elements_per_pe; i++)
+	my_data[i] = my_rank * 10 + i;
+
+    /* Write some data with distributed arrays. */
+    if (nc_put_vard_int(ncid, varid, ioid, 0, my_data)) PERR;
+    if (nc_close(ncid)) PERR;
+
+    /* Open the file. */
+    if (nc_open(FILE_NAME, NC_PIO, &ncid)) PERR;
+
+    /* Read distributed arrays. */
+    if (!(data_in = malloc(elements_per_pe * sizeof(int)))) PERR;
+    if (nc_get_vard_int(ncid, varid, ioid, 0, data_in)) PERR;
+
+    /* Check results. */
+    for (i = 0; i < elements_per_pe; i++)
+	if (data_in[i] != my_data[i]) PERR;
+
+    /* Close file. */
+    if (nc_close(ncid)) PERR;
+
+    /* Free resources. */
+    free(data_in);
+    free(my_data);
+    if (nc_free_decomp(ioid)) PERR;
+
+    return 0;
+}
 
 int
 main(int argc, char **argv)
 {
+    int iosysid;
     int my_rank;
     int ntasks;
 
@@ -38,89 +102,16 @@ main(int argc, char **argv)
 
     if (!my_rank)
         printf("\n*** Testing netCDF integration layer.\n");
-    if (!my_rank)
-        printf("*** testing getting/setting of default iosystemid...");
-    {
-        int iosysid;
-
-        if (nc_set_iosystem(TEST_VAL_42)) PERR;
-        if (nc_get_iosystem(&iosysid)) PERR;
-        if (iosysid != TEST_VAL_42) PERR;
-    }
-    PSUMMARIZE_ERR;
 
     if (!my_rank)
-        printf("*** testing simple use of netCDF integration layer format...");
-    {
-        int ncid, ioid;
-        int dimid[NDIM3], varid;
-        int dimlen[NDIM3] = {NC_UNLIMITED, DIM_LEN_X, DIM_LEN_Y};
-        int iosysid;
-        NC_Dispatch *disp_in;
-        size_t elements_per_pe;
-        size_t *compdof; /* The decomposition mapping. */
-        int *my_data;
-        int *data_in;
-        int i;
-
-        /* Turn on logging for PIO library. */
-        /* PIOc_set_log_level(3); */
-
-        /* Initialize the intracomm. */
-        if (nc_def_iosystem(MPI_COMM_WORLD, 1, 1, 0, 0, &iosysid)) PERR;
-
-        /* Create a file with a 3D record var. */
-        if (nc_create(FILE_NAME, NC_PIO, &ncid)) PERR;
-        if (nc_def_dim(ncid, DIM_NAME_UNLIMITED, dimlen[0], &dimid[0])) PERR;
-        if (nc_def_dim(ncid, DIM_NAME_X, dimlen[1], &dimid[1])) PERR;
-        if (nc_def_dim(ncid, DIM_NAME_Y, dimlen[2], &dimid[2])) PERR;
-        if (nc_def_var(ncid, VAR_NAME, NC_INT, NDIM3, dimid, &varid)) PERR;
-
-        /* Calculate a decomposition for distributed arrays. */
-        elements_per_pe = DIM_LEN_X * DIM_LEN_Y / ntasks;
-        if (!(compdof = malloc(elements_per_pe * sizeof(size_t))))
-            PERR;
-        for (i = 0; i < elements_per_pe; i++)
-            compdof[i] = my_rank * elements_per_pe + i;
-
-        /* Create the PIO decomposition for this test. */
-        if (nc_def_decomp(iosysid, PIO_INT, NDIM2, &dimlen[1], elements_per_pe,
-                          compdof, &ioid, 1, NULL, NULL)) PERR;
-        free(compdof);
-
-        /* Create some data on this processor. */
-        if (!(my_data = malloc(elements_per_pe * sizeof(int)))) PERR;
-        for (i = 0; i < elements_per_pe; i++)
-            my_data[i] = my_rank * 10 + i;
-
-        /* Write some data with distributed arrays. */
-        if (nc_put_vard_int(ncid, varid, ioid, 0, my_data)) PERR;
-        if (nc_close(ncid)) PERR;
-
-        /* Check that our user-defined format has been added. */
-        if (nc_inq_user_format(NC_PIO, &disp_in, NULL)) PERR;
-        if (disp_in != &NCINT_dispatcher) PERR;
-
-        /* Open the file. */
-        if (nc_open(FILE_NAME, NC_PIO, &ncid)) PERR;
-
-        /* Read distributed arrays. */
-        if (!(data_in = malloc(elements_per_pe * sizeof(int)))) PERR;
-        if (nc_get_vard_int(ncid, varid, ioid, 0, data_in)) PERR;
-
-        /* Check results. */
-        for (i = 0; i < elements_per_pe; i++)
-            if (data_in[i] != my_data[i]) PERR;
-
-        /* Close file. */
-        if (nc_close(ncid)) PERR;
-
-        /* Free resources. */
-        free(data_in);
-        free(my_data);
-        if (nc_free_decomp(ioid)) PERR;
-        if (nc_free_iosystem(iosysid)) PERR;
-    }
+        printf("*** testing var compression with netCDF integration layer...");
+
+    /* Initialize the intracomm. */
+    if (nc_def_iosystem(MPI_COMM_WORLD, 1, 1, 0, 0, &iosysid)) PERR;
+
+    if (run_var_compress_test(my_rank, ntasks, iosysid)) PERR;
+
+    if (nc_free_iosystem(iosysid)) PERR;
     PSUMMARIZE_ERR;
 
     /* Finalize MPI. */