diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 324b34ce8..bd062ed40 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -218,7 +218,7 @@ if( ENABLE_EXTRA_TESTS AND HAVE_ECCODES_THREADS )
                       COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/grib_encode_pthreads.sh
     )
 
-    foreach( test grib_ecc-604-1 grib_ecc-604-2 grib_ecc-604-3 )
+    foreach( test grib_ecc-604 )
         ecbuild_add_executable( TARGET    ${test}
                                 NOINSTALL
                                 SOURCES   ${test}.c
diff --git a/tests/grib_ecc-604-2.c b/tests/grib_ecc-604-2.c
deleted file mode 100644
index 9af8aa832..000000000
--- a/tests/grib_ecc-604-2.c
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * Test for ECC-604: Each thread creates a new GRIB handle and writes it out.
- *                   It does not clone the handle.
- */
-
-#include <time.h>
-#include <pthread.h>
-#include <assert.h>
-
-#include "grib_api.h"
-
-/* These are passed in via argv */
-static size_t NUM_THREADS         = 0;
-static size_t FILES_PER_ITERATION = 0;
-static char*  INPUT_FILE          = NULL;
-
-static int encode_file(char *template_file, char *output_file)
-{
-    FILE *in, *out;
-    grib_handle *source_handle = NULL;
-    const void *buffer = NULL;
-    size_t size = 0;
-    int err = 0;
-    double *values;
-
-    in = fopen(template_file,"r"); assert(in);
-    out = fopen(output_file,"w");  assert(out);
-
-    /* loop over the messages in the source GRIB */
-    while ((source_handle = grib_handle_new_from_file(0, in, &err))!=NULL) {
-        int i;
-        size_t values_len = 0;
-        size_t str_len = 20;
-
-        /*GRIB_CHECK(grib_set_long(source_handle, "centre", 250),0);*/
-        GRIB_CHECK(grib_get_size(source_handle, "values", &values_len),0);
-
-        values = (double*)malloc(values_len*sizeof(double));
-        GRIB_CHECK(grib_get_double_array(source_handle, "values", values, &values_len),0);
-
-        for (i=0;i<values_len;i++) {
-            values[i] *= 0.9;
-        }
-
-        GRIB_CHECK(grib_set_string(source_handle,"stepUnits", "s", &str_len),0);
-        GRIB_CHECK(grib_set_long(source_handle, "startStep", 43200), 0);
-        GRIB_CHECK(grib_set_long(source_handle, "endStep", 86400), 0);
-        GRIB_CHECK(grib_set_long(source_handle, "bitsPerValue", 16),0);
-
-        /* set data values */
-        GRIB_CHECK(grib_set_double_array(source_handle,"values",values,values_len),0);
-
-        GRIB_CHECK(grib_get_message(source_handle,&buffer,&size),0);
-        if(fwrite(buffer,1,size,out) != size) {
-            perror(output_file);
-            return 1;
-        }
-        {
-            FILE *devnull = fopen("/dev/null", "w");
-            grib_dump_content(source_handle,devnull,"debug",0,NULL);
-        }
-        grib_handle_delete(source_handle);
-        free(values);
-    }
-
-    fclose(out);
-    fclose(in);
-
-    return 0;
-}
-
-void do_stuff(void *data);
-
-/* Structure for passing data to threads */
-struct v {
-    size_t number;
-    char *data;
-};
-
-void *runner(void *ptr); /* the thread */
-
-int main(int argc, char **argv)
-{
-    size_t i;
-    int thread_counter = 0;
-    int parallel = 1;
-    const char* prog = argv[0];
-    char* mode;
-    if (argc!=5) {
-        fprintf(stderr, "Usage:\n\t%s seq file numRuns numIter\nOr\n\t%s par file numThreads numIter\n", prog, prog);
-        return 1;
-    }
-    mode = argv[1];
-    INPUT_FILE= argv[2];
-    NUM_THREADS = atol(argv[3]);
-    FILES_PER_ITERATION = atol(argv[4]);
-
-    if (strcmp(mode,"seq")==0) {
-        parallel = 0;
-    }
-    if (parallel) {
-        printf("Running parallel in %ld threads. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
-        printf("Each thread creates a new GRIB handle and writes it out. No cloning the handle\n");
-    } else {
-        printf("Running sequentially in %ld runs. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
-    }
-
-    {
-        pthread_t workers[NUM_THREADS];
-        for (i = 0; i < NUM_THREADS; i++) {
-            struct v *data = (struct v *) malloc(sizeof(struct v));
-            data->number = i;
-            data->data = NULL;
-
-            if (parallel) {
-                /* Now we will create the thread passing it data as an argument */
-                pthread_create(&workers[thread_counter], NULL, runner, data);
-                /*pthread_join(workers[thread_counter], NULL);*/
-                thread_counter++;
-            } else {
-                do_stuff(data);
-            }
-        }
-
-        if (parallel) {
-            for (i = 0; i < NUM_THREADS; i++)  {
-                pthread_join(workers[i], NULL);
-            }
-        }
-    }
-
-    return 0;
-}
-
-void *runner(void *ptr)
-{
-    do_stuff(ptr);
-    pthread_exit(0);
-}
-
-void do_stuff(void *ptr)
-{
-    /* Cast argument to struct v pointer */
-    struct v *data = ptr;
-    size_t i;
-    char output_file[50];
-    time_t ltime;
-    struct tm result;
-    char stime[32];
-
-    for (i=0; i<FILES_PER_ITERATION;i++) {
-        sprintf(output_file,"output/output_file_%ld-%ld.grib", data->number, i);
-        encode_file(INPUT_FILE,output_file);
-    }
-
-    ltime = time(NULL);
-    localtime_r(&ltime, &result);
-    strftime(stime, 32, "%H:%M:%S", &result); /* Try to get milliseconds here too*/
-    /* asctime_r(&result, stime); */
-
-    printf("%s: Worker %ld finished.\n", stime, data->number);
-}
diff --git a/tests/grib_ecc-604-3.c b/tests/grib_ecc-604-3.c
deleted file mode 100644
index e484e1253..000000000
--- a/tests/grib_ecc-604-3.c
+++ /dev/null
@@ -1,159 +0,0 @@
-/*
- * Test for ECC-604: Each thread creates a new GRIB handle and clones it.
- *                   No output writing.
- */
-#include <time.h>
-#include <pthread.h>
-#include <assert.h>
-
-#include "grib_api.h"
-
-/* These are passed in via argv */
-static size_t NUM_THREADS         = 0;
-static size_t FILES_PER_ITERATION = 0;
-static char*  INPUT_FILE          = NULL;
-
-static int decode_file(char *template_file)
-{
-    FILE *in;
-    grib_handle *source_handle = NULL;
-    const void *buffer = NULL;
-    size_t size = 0;
-    int err = 0;
-    double *values;
-
-    in = fopen(template_file,"r"); assert(in);
-
-    /* loop over the messages in the source GRIB and clone them */
-    while ((source_handle = grib_handle_new_from_file(0, in, &err))!=NULL) {
-        int i;
-        size_t values_len = 0;
-        size_t str_len = 20;
-
-        grib_handle *clone_handle = grib_handle_clone(source_handle);
-        assert(clone_handle);
-
-        /*GRIB_CHECK(grib_set_long(clone_handle, "centre", 250),0);*/
-        GRIB_CHECK(grib_get_size(clone_handle, "values", &values_len),0);
-
-        values = (double*)malloc(values_len*sizeof(double));
-        GRIB_CHECK(grib_get_double_array(clone_handle, "values", values, &values_len),0);
-
-        for (i=0;i<values_len;i++) {
-            values[i] *= 0.9;
-        }
-
-        GRIB_CHECK(grib_set_string(clone_handle,"stepUnits", "s", &str_len),0);
-        GRIB_CHECK(grib_set_long(clone_handle, "startStep", 43200), 0);
-        GRIB_CHECK(grib_set_long(clone_handle, "endStep", 86400), 0);
-        GRIB_CHECK(grib_set_long(clone_handle, "bitsPerValue", 16),0);
-
-        /* set data values */
-        GRIB_CHECK(grib_set_double_array(clone_handle,"values",values,values_len),0);
-
-        GRIB_CHECK(grib_get_message(clone_handle,&buffer,&size),0);
-
-        {
-            FILE *devnull = fopen("/dev/null", "w");
-            grib_dump_content(source_handle, devnull, "debug", 0, NULL);
-            grib_dump_content(clone_handle,  devnull, "debug", 0, NULL);
-        }
-
-        grib_handle_delete(clone_handle);
-        grib_handle_delete(source_handle);
-        free(values);
-    }
-
-    fclose(in);
-
-    return 0;
-}
-
-void do_stuff(void *data);
-
-/* Structure for passing data to threads */
-struct v {
-    size_t number;
-    char *data;
-};
-
-void *runner(void *ptr); /* the thread */
-
-int main(int argc, char **argv)
-{
-    size_t i;
-    int thread_counter = 0;
-    int parallel = 1;
-    const char* prog = argv[0];
-    char* mode;
-    if (argc!=5) {
-        fprintf(stderr, "Usage:\n\t%s seq file numRuns numIter\nOr\n\t%s par file numThreads numIter\n", prog, prog);
-        return 1;
-    }
-    mode = argv[1];
-    INPUT_FILE= argv[2];
-    NUM_THREADS = atol(argv[3]);
-    FILES_PER_ITERATION = atol(argv[4]);
-
-    if (strcmp(mode,"seq")==0) {
-        parallel = 0;
-    }
-    if (parallel) {
-        printf("Running parallel in %ld threads. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
-        printf("Each thread creates a new GRIB handle and clones it. No output writing\n");
-    } else {
-        printf("Running sequentially in %ld runs. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
-    }
-
-    {
-        pthread_t workers[NUM_THREADS];
-        for (i = 0; i < NUM_THREADS; i++) {
-            struct v *data = (struct v *) malloc(sizeof(struct v));
-            data->number = i;
-            data->data = NULL;
-
-            if (parallel) {
-                /* Now we will create the thread passing it data as an argument */
-                pthread_create(&workers[thread_counter], NULL, runner, data);
-                /*pthread_join(workers[thread_counter], NULL);*/
-                thread_counter++;
-            } else {
-                do_stuff(data);
-            }
-        }
-
-        if (parallel) {
-            for (i = 0; i < NUM_THREADS; i++)  {
-                pthread_join(workers[i], NULL);
-            }
-        }
-    }
-    return 0;
-}
-
-void *runner(void *ptr)
-{
-    do_stuff(ptr);
-    pthread_exit(0);
-}
-
-void do_stuff(void *ptr)
-{
-    /* Cast argument to struct v pointer */
-    struct v *data = ptr;
-    size_t i;
-    time_t ltime;
-    struct tm result;
-    char stime[32];
-
-    for (i=0; i<FILES_PER_ITERATION;i++) {
-        decode_file(INPUT_FILE);
-    }
-
-    ltime = time(NULL);
-    localtime_r(&ltime, &result);
-    strftime(stime, 32, "%H:%M:%S", &result); /* Try to get milliseconds here too*/
-    /* asctime_r(&result, stime); */
-
-    printf("%s: Worker %ld finished.\n", stime, data->number);
-}
diff --git a/tests/grib_ecc-604-1.c b/tests/grib_ecc-604.c
similarity index 62%
rename from tests/grib_ecc-604-1.c
rename to tests/grib_ecc-604.c
index d5e0ff3ae..8e2de7252 100644
--- a/tests/grib_ecc-604-1.c
+++ b/tests/grib_ecc-604.c
@@ -4,6 +4,7 @@
 #include <time.h>
 #include <pthread.h>
 #include <assert.h>
+#include <unistd.h>
 
 #include "grib_api.h"
 
@@ -11,6 +12,8 @@
 static size_t NUM_THREADS         = 0;
 static size_t FILES_PER_ITERATION = 0;
 static char*  INPUT_FILE          = NULL;
+int opt_clone = 0; /* If 1 then clone source handle */
+int opt_write = 0; /* If 1 write handle to file */
 
 static int encode_file(char *template_file, char *output_file)
 {
@@ -22,51 +25,56 @@ static int encode_file(char *template_file, char *output_file)
     double *values;
 
     in = fopen(template_file,"r"); assert(in);
-    out = fopen(output_file,"w");  assert(out);
+    if (output_file) {
+        out = fopen(output_file,"w");  assert(out);
+    }
 
     /* loop over the messages in the source GRIB and clone them */
     while ((source_handle = grib_handle_new_from_file(0, in, &err))!=NULL) {
         int i;
         size_t values_len = 0;
         size_t str_len = 20;
+        grib_handle *h = source_handle;
+        
+        if (opt_clone) {
+            h = grib_handle_clone(source_handle); assert(h);
+        }
 
-        grib_handle *clone_handle = grib_handle_clone(source_handle);
-        assert(clone_handle);
-
-        /*GRIB_CHECK(grib_set_long(clone_handle, "centre", 250),0);*/
-        GRIB_CHECK(grib_get_size(clone_handle, "values", &values_len),0);
+        GRIB_CHECK(grib_get_size(h, "values", &values_len),0);
 
         values = (double*)malloc(values_len*sizeof(double));
-        GRIB_CHECK(grib_get_double_array(clone_handle, "values", values, &values_len),0);
+        GRIB_CHECK(grib_get_double_array(h, "values", values, &values_len),0);
 
         for (i=0;i<values_len;i++) {
             values[i] *= 0.9;
         }
 
-        GRIB_CHECK(grib_set_string(clone_handle,"stepUnits", "s", &str_len),0);
-        GRIB_CHECK(grib_set_long(clone_handle, "startStep", 43200), 0);
-        GRIB_CHECK(grib_set_long(clone_handle, "endStep", 86400), 0);
-        GRIB_CHECK(grib_set_long(clone_handle, "bitsPerValue", 16),0);
+        GRIB_CHECK(grib_set_string(h,"stepUnits", "s", &str_len),0);
+        GRIB_CHECK(grib_set_long(h, "startStep", 43200), 0);
+        GRIB_CHECK(grib_set_long(h, "endStep", 86400), 0);
+        GRIB_CHECK(grib_set_long(h, "bitsPerValue", 16),0);
 
         /* set data values */
-        GRIB_CHECK(grib_set_double_array(clone_handle,"values",values,values_len),0);
+        GRIB_CHECK(grib_set_double_array(h,"values",values,values_len),0);
 
-        GRIB_CHECK(grib_get_message(clone_handle,&buffer,&size),0);
-        if(fwrite(buffer,1,size,out) != size) {
-            perror(output_file);
-            return 1;
+        GRIB_CHECK(grib_get_message(h,&buffer,&size),0);
+        if (output_file) {
+            if(fwrite(buffer,1,size,out) != size) {
+                perror(output_file);
+                return 1;
+            }
         }
         {
             FILE *devnull = fopen("/dev/null", "w");
             grib_dump_content(source_handle,devnull, "debug", 0, NULL);
-            grib_dump_content(clone_handle, devnull, "debug", 0, NULL);
         }
-        grib_handle_delete(clone_handle);
+
         grib_handle_delete(source_handle);
+        if(opt_clone) grib_handle_delete(h);
         free(values);
     }
 
-    fclose(out);
+    if (output_file) fclose(out);
     fclose(in);
 
     return 0;
@@ -86,24 +94,32 @@ int main(int argc, char **argv)
 {
     size_t i;
     int thread_counter = 0;
-    int parallel = 1;
+    int parallel=1, index=0, c=0;
     const char* prog = argv[0];
     char* mode;
-    if (argc!=5) {
-        fprintf(stderr, "Usage:\n\t%s seq file numRuns numIter\nOr\n\t%s par file numThreads numIter\n", prog, prog);
+    if (argc<5 || argc>7) {
+        fprintf(stderr, "Usage:\n\t%s [options] seq file numRuns numIter\nOr\n\t%s [options] par file numThreads numIter\n", prog, prog);
         return 1;
     }
-    mode = argv[1];
-    INPUT_FILE= argv[2];
-    NUM_THREADS = atol(argv[3]);
-    FILES_PER_ITERATION = atol(argv[4]);
+    
+    while ((c = getopt (argc, argv, "cw")) != -1) {
+        switch (c) {
+            case 'c': opt_clone=1; break;
+            case 'w': opt_write=1; break;
+        }
+    }
+    index = optind;
+    mode = argv[index];
+    INPUT_FILE = argv[index+1];
+    NUM_THREADS = atol(argv[index+2]);
+    FILES_PER_ITERATION = atol(argv[index+3]);
 
     if (strcmp(mode,"seq")==0) {
         parallel = 0;
     }
     if (parallel) {
         printf("Running parallel in %ld threads. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
-        printf("Each thread creates a new GRIB handle, clones it and writes it out\n");
+        printf("Options: clone=%d, write=%d\n", opt_clone, opt_write);
     } else {
         printf("Running sequentially in %ld runs. %ld iterations\n", NUM_THREADS, FILES_PER_ITERATION);
     }
@@ -152,8 +168,12 @@ void do_stuff(void *ptr)
     char stime[32];
 
     for (i=0; i<FILES_PER_ITERATION;i++) {
-        sprintf(output_file,"output/output_file_%ld-%ld.grib", data->number, i);
-        encode_file(INPUT_FILE,output_file);
+        if (opt_write) {
+            sprintf(output_file,"output/output_file_%ld-%ld.grib", data->number, i);
+            encode_file(INPUT_FILE,output_file);
+        } else {
+            encode_file(INPUT_FILE,NULL);
+        }
     }
 
     ltime = time(NULL);
diff --git a/tests/grib_ecc-604.sh b/tests/grib_ecc-604.sh
index a11f97dcb..4a22eab98 100755
--- a/tests/grib_ecc-604.sh
+++ b/tests/grib_ecc-604.sh
@@ -36,19 +36,19 @@ process()
     # Test 01: Clone + output
     # ------------------------
     rm -fr $OUTPUT;   mkdir -p $OUTPUT
-    time ${test_dir}/grib_ecc-604-1 par $input $NUM_THREADS $NUM_ITER
+    time ${test_dir}/grib_ecc-604 -c -w par $input $NUM_THREADS $NUM_ITER
     validate
 
     # Test 02: No clone + output
     # --------------------------
     rm -fr $OUTPUT;   mkdir -p $OUTPUT
-    time ${test_dir}/grib_ecc-604-2 par $input $NUM_THREADS $NUM_ITER
+    time ${test_dir}/grib_ecc-604 -w par $input $NUM_THREADS $NUM_ITER
     validate
 
     # Test 03: Clone + no output
     # ---------------------------
     rm -fr $OUTPUT
-    time ${test_dir}/grib_ecc-604-3 par $input $NUM_THREADS $NUM_ITER
+    time ${test_dir}/grib_ecc-604 -c par $input $NUM_THREADS $NUM_ITER
     # Nothing to validate as there is no output
 }
 ###################################################