Let tests provide a "hook" that runs after each step in create_zoo().

Provide a hook in vfd_swmr_zoo_writer that calls H5Fvfd_swmr_end_tick().

test/Makefile.am

@@ -146,7 +146,7 @@ else
   noinst_LTLIBRARIES=libh5test.la
 endif
 
-libh5test_la_SOURCES=h5test.c testframe.c cache_common.c swmr_common.c external_common.c vfd_swmr_common.c
+libh5test_la_SOURCES=h5test.c testframe.c cache_common.c swmr_common.c external_common.c stubs.c vfd_swmr_common.c
 
 # Use libhd5test.la to compile all of the tests
 LDADD=libh5test.la $(LIBHDF5)

test/genall5.c

@@ -3192,6 +3192,7 @@ tend_zoo(hid_t fid, const char *base_path, int proc_num, bool skip_varlen,
             !create_or_validate_selection(fid, full_path, proc_num, i,
                 skip_varlen, false))
             break;
+        zoo_create_hook(fid);
         if (!create_or_validate_selection(fid, full_path, proc_num, i,
                 skip_varlen, true))
             break;

test/genall5.h

@@ -51,3 +51,9 @@ void vrfy_ds_cpt_i(hid_t fid, const char *dset_name, hbool_t write_data);
 void ds_ctg_v(hid_t fid, const char *dset_name, hbool_t write_data);
 void vrfy_ds_ctg_v(hid_t fid, const char *dset_name, hbool_t write_data);
 
+/* Individual tests can override zoo_create_hook(), which is called
+ * after each step of create_zoo().  The `hid_t` argument identifies
+ * the file where the step was performed.  The test library provides a
+ * default implementation of zoo_create_hook() that does nothing.
+ */
+void zoo_create_hook(hid_t);

test/stubs.c

@@ -0,0 +1,25 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+#include "h5test.h"
+#include "genall5.h"
+
+/* The default, do-nothing implementation of zoo_create_hook(), which
+ * is called after each create_zoo() step.
+ */
+void
+zoo_create_hook(hid_t H5_ATTR_UNUSED fid)
+{
+    return;
+}
+

test/vfd_swmr_zoo_writer.c

@@ -53,6 +53,13 @@ print_cache_hits(H5C_t *cache)
     dbgf(3, "\n");
 }
 
+void
+zoo_create_hook(hid_t fid)
+{
+    dbgf(3, "%s: enter\n", __func__);
+    H5Fvfd_swmr_end_tick(fid);
+}
+
 static void
 usage(const char *progname)
 {