diff --git a/testing/fopencookie/Kconfig b/testing/fopencookie/Kconfig
new file mode 100644
index 000000000..cc14780d3
--- /dev/null
+++ b/testing/fopencookie/Kconfig
@@ -0,0 +1,13 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config TESTING_FOPENCOOKIE_TEST
+	tristate "Fopencookie test tool"
+	default n
+	---help---
+		Performs a basic operations with fopencookie call.
+
+if TESTING_FOPENCOOKIE_TEST
+endif
diff --git a/testing/fopencookie/Make.defs b/testing/fopencookie/Make.defs
new file mode 100644
index 000000000..e9ff32601
--- /dev/null
+++ b/testing/fopencookie/Make.defs
@@ -0,0 +1,23 @@
+############################################################################
+# apps/testing/fopencookie/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+ifneq ($(CONFIG_TESTING_FOPENCOOKIE_TEST),)
+CONFIGURED_APPS += $(APPDIR)/testing/fopencookie
+endif
diff --git a/testing/fopencookie/Makefile b/testing/fopencookie/Makefile
new file mode 100644
index 000000000..e1c364c65
--- /dev/null
+++ b/testing/fopencookie/Makefile
@@ -0,0 +1,32 @@
+############################################################################
+# apps/testing/fopencookie/Makefile
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+############################################################################
+
+include $(APPDIR)/Make.defs
+
+# SMART filesystem test tool
+
+PROGNAME = fopencookie_test
+PRIORITY = SCHED_PRIORITY_DEFAULT
+STACKSIZE = 4096
+MODULE = $(CONFIG_TESTING_FOPENCOOKIE_TEST)
+
+MAINSRC = fopencookie.c
+
+include $(APPDIR)/Application.mk
diff --git a/testing/fopencookie/README.md b/testing/fopencookie/README.md
new file mode 100644
index 000000000..d24d04733
--- /dev/null
+++ b/testing/fopencookie/README.md
@@ -0,0 +1,13 @@
+# Testing / `fopencookie` Fopencookie
+
+Performs a basic operations with fopencookie call.
+
+```conf
+CONFIG_TESTING_SMART_TEST=y
+```
+
+```
+Usage:
+
+    fopencookie
+```
diff --git a/testing/fopencookie/fopencookie.c b/testing/fopencookie/fopencookie.c
new file mode 100644
index 000000000..c69277899
--- /dev/null
+++ b/testing/fopencookie/fopencookie.c
@@ -0,0 +1,309 @@
+/****************************************************************************
+ * apps/testing/fopencookie/fopencookie.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define BUF_SIZE 32
+
+/****************************************************************************
+ * Private data
+ ****************************************************************************/
+
+struct my_cookie
+{
+  char   *buf;
+  size_t  endpos;
+  size_t  bufsize;
+  off_t   offset;
+};
+
+static const char correctbuf[] = "abcdefghijklmnopqrstuvwxyz";
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+ssize_t fopencookie_write_hook(void *c, const char *buf, size_t size)
+{
+  char *new_buff;
+  off_t realloc_size;
+  struct my_cookie *cookie = (struct my_cookie *)c;
+
+  DEBUGASSERT(c != NULL);
+
+  if (size + cookie->offset > cookie->bufsize)
+    {
+      realloc_size = size + cookie->offset - cookie->bufsize + 1;
+      new_buff = realloc(cookie->buf, realloc_size);
+      if (new_buff == NULL)
+        {
+          fprintf(stderr, "ERROR: Cannot reallocate memory!\n");
+          return -1;
+        }
+
+      cookie->buf = new_buff;
+      cookie->bufsize = realloc_size;
+    }
+
+  memcpy(cookie->buf + cookie->offset, buf, size);
+
+  cookie->offset += size;
+  if (cookie->offset > cookie->endpos)
+    {
+      cookie->endpos = cookie->offset;
+    }
+
+  return size;
+}
+
+ssize_t fopencookie_read_hook(void *c, char *buf, size_t size)
+{
+  struct my_cookie *cookie = (struct my_cookie *)c;
+
+  if (cookie->offset + size > cookie->endpos)
+    {
+      size = cookie->endpos - cookie->offset;
+    }
+
+  if (size < 0)
+    {
+      size = 0;
+    }
+
+  memcpy(buf, cookie->buf + cookie->offset, size);
+
+  cookie->offset += size;
+  return size;
+}
+
+off_t fopencookie_seek_hook(void *c, off_t *offset, int whence)
+{
+  off_t new_offset;
+  struct my_cookie *cookie = (struct my_cookie *)c;
+
+  if (whence == SEEK_SET)
+    {
+      new_offset = *offset;
+    }
+
+  else if (whence == SEEK_END)
+    {
+      new_offset = cookie->endpos + *offset;
+    }
+
+  else if (whence == SEEK_CUR)
+    {
+      new_offset = cookie->offset + *offset;
+    }
+
+  else
+    {
+      return -1;
+    }
+
+  if (new_offset < 0)
+    {
+      return -1;
+    }
+
+  cookie->offset = new_offset;
+  *offset = new_offset;
+  return new_offset;
+}
+
+int fopencookie_close_hook(void *c)
+{
+  struct my_cookie *cookie = (struct my_cookie *)c;
+
+  cookie->bufsize = 0;
+
+  return OK;
+}
+
+/****************************************************************************
+ * Name: fopencookie_write_test
+ ****************************************************************************/
+
+static int fopencookie_write_test(FILE *stream)
+{
+  int n;
+
+  n = fputs(correctbuf, stream);
+  if (n < 0)
+    {
+      printf("fopencookie_write_test: fputs failed: %d\n", -errno);
+      return -1;
+    }
+
+  printf("fopencookie_write_test: written buffer: %.*s\n", n, correctbuf);
+  printf("fopencookie_write_test: succesfull\n");
+  return 0;
+}
+
+/****************************************************************************
+ * Name: fopencookie_write_test
+ ****************************************************************************/
+
+static int fopencookie_read_test(FILE *stream)
+{
+  int n;
+  int endpos;
+  char buf[256];
+
+  fseek(stream, 0, SEEK_END);
+  endpos = ftell(stream);
+  fseek(stream, 0, SEEK_SET);
+
+  n = fread(buf, 1, endpos, stream);
+
+  for (int i = 0; i < n; i++)
+    {
+      if (correctbuf[i] != buf[i])
+        {
+          printf("fopencookie_write_test: error %d got %c, expected %c\n", i,
+                 buf[i], correctbuf[i]);
+          return -1;
+        }
+    }
+
+  printf("fopencookie_read_test: read buffer: %.*s\n", n, correctbuf);
+  printf("fopencookie_read_test: succesfull\n");
+  return 0;
+}
+
+/****************************************************************************
+ * Name: fopencookie_seek_test
+ ****************************************************************************/
+
+static int fopencookie_seek_test(FILE *stream)
+{
+  int endpos;
+  int i;
+  int n;
+  char buf[1];
+
+  fseek(stream, 0, SEEK_END);
+  endpos = ftell(stream);
+  fseek(stream, 0, SEEK_SET);
+
+  for (i = 0; i < endpos; i += 2)
+    {
+      fseek(stream, i, SEEK_SET);
+      n = fread(buf, 1, 1, stream);
+      if (n != 1)
+        {
+          printf("fopencookie_seek_test: read at %i failed\n", i);
+        }
+
+      if (correctbuf[i] != buf[0])
+        {
+          printf("fopencookie_seek_test: error %d got %c, expected %c\n", i,
+                 buf[0], correctbuf[i]);
+          return -1;
+        }
+
+      printf("fopencookie_seek_test: pos %d, char %c\n", i, buf[i]);
+    }
+
+  printf("fopencookie_seek_test: succesfull\n");
+
+  fseek(stream, 0, SEEK_SET);
+  return 0;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+int main(int argc, FAR char *argv[])
+{
+  int ret;
+  FILE *stream;
+  struct my_cookie mycookie;
+  cookie_io_functions_t cookie_funcs =
+    {
+      .read  = fopencookie_read_hook,
+      .write = fopencookie_write_hook,
+      .seek  = fopencookie_seek_hook,
+      .close = fopencookie_close_hook
+    };
+
+  /* Set up the cookie before calling fopencookie(). */
+
+  mycookie.buf = malloc(BUF_SIZE);
+  if (mycookie.buf == NULL)
+    {
+      printf("Could not allocate memory for cookie.\n");
+      return -1;
+    }
+
+  mycookie.bufsize = BUF_SIZE;
+  mycookie.offset = 0;
+  mycookie.endpos = 0;
+
+  stream = fopencookie(&mycookie, "w+", cookie_funcs);
+  if (stream == NULL)
+    {
+      free(mycookie.buf);
+      return -1;
+    }
+
+  ret = fopencookie_write_test(stream);
+  if (ret < 0)
+    {
+      goto fopencookie_ret;
+    }
+
+  ret = fopencookie_read_test(stream);
+  if (ret < 0)
+    {
+      goto fopencookie_ret;
+    }
+
+  ret = fopencookie_seek_test(stream);
+  if (ret < 0)
+    {
+      goto fopencookie_ret;
+    }
+
+  printf("fopencokie tests were succesfull.\n");
+
+fopencookie_ret:
+  fclose(stream);
+  free(mycookie.buf);
+
+  return ret;
+}