diff --git a/TESTS/filesystem/dirs/main.cpp b/TESTS/filesystem/dirs/main.cpp
new file mode 100644
index 0000000000..9a37cfae08
--- /dev/null
+++ b/TESTS/filesystem/dirs/main.cpp
@@ -0,0 +1,472 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+#include <stdlib.h>
+#include <errno.h>
+
+using namespace utest::v1;
+
+// test configuration
+#ifndef MBED_TEST_FILESYSTEM
+#define MBED_TEST_FILESYSTEM FATFileSystem
+#endif
+
+#ifndef MBED_TEST_FILESYSTEM_DECL
+#define MBED_TEST_FILESYSTEM_DECL MBED_TEST_FILESYSTEM fs("fs")
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE
+#define MBED_TEST_BLOCKDEVICE SDBlockDevice
+#define MBED_TEST_BLOCKDEVICE_DECL SDBlockDevice bd(MBED_CONF_SD_SPI_MOSI, MBED_CONF_SD_SPI_MISO, MBED_CONF_SD_SPI_CLK, MBED_CONF_SD_SPI_CS);
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE_DECL
+#define MBED_TEST_BLOCKDEVICE_DECL MBED_TEST_BLOCKDEVICE bd
+#endif
+
+#ifndef MBED_TEST_FILES
+#define MBED_TEST_FILES 4
+#endif
+
+#ifndef MBED_TEST_DIRS
+#define MBED_TEST_DIRS 4
+#endif
+
+#ifndef MBED_TEST_BUFFER
+#define MBED_TEST_BUFFER 8192
+#endif
+
+#ifndef MBED_TEST_TIMEOUT
+#define MBED_TEST_TIMEOUT 120
+#endif
+
+
+// declarations
+#define STRINGIZE(x) STRINGIZE2(x)
+#define STRINGIZE2(x) #x
+#define INCLUDE(x) STRINGIZE(x.h)
+
+#include INCLUDE(MBED_TEST_FILESYSTEM)
+#include INCLUDE(MBED_TEST_BLOCKDEVICE)
+
+MBED_TEST_FILESYSTEM_DECL;
+MBED_TEST_BLOCKDEVICE_DECL;
+
+Dir dir[MBED_TEST_DIRS];
+File file[MBED_TEST_FILES];
+DIR *dd[MBED_TEST_DIRS];
+FILE *fd[MBED_TEST_FILES];
+struct dirent ent;
+struct dirent *ed;
+size_t size;
+uint8_t buffer[MBED_TEST_BUFFER];
+uint8_t rbuffer[MBED_TEST_BUFFER];
+uint8_t wbuffer[MBED_TEST_BUFFER];
+
+
+// tests
+
+void test_directory_tests() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = MBED_TEST_FILESYSTEM::format(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_root_directory() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "/");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_directory_creation() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("potato", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_file_creation() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "burito", O_CREAT | O_WRONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void dir_file_check(char *list[], uint32_t elements) {
+    int res;
+    while(1) {
+        res = dir[0].read(&ent);
+        if (0 == res) {
+            break;
+        }
+        for (int i = 0; i < elements ; i++) {
+            res = strcmp(ent.d_name, list[i]);
+            if (0 == res) {
+                res = ent.d_type;
+                if ((DT_DIR != res) && (DT_REG != res)) {
+                    TEST_ASSERT(1);
+                }
+                break;
+            }
+            else if( i == elements) {
+                TEST_ASSERT_EQUAL(0, res);
+            }
+        }
+    }
+}
+
+void test_directory_iteration() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    res = fs.mount(&bd);
+    TEST_ASSERT_EQUAL(0, res);
+    res = dir[0].open(&fs, "/");
+    TEST_ASSERT_EQUAL(0, res);
+    char *dir_list[] = {"potato", "burito", ".", ".."};
+
+    dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+
+    res = dir[0].close();
+    TEST_ASSERT_EQUAL(0, res);
+    res = fs.unmount();
+    TEST_ASSERT_EQUAL(0, res);
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_directory_failures() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("potato", 0777);
+        TEST_ASSERT_EQUAL(-EEXIST, res);
+        res = dir[0].open(&fs, "tomato");
+        TEST_ASSERT_EQUAL(-ENOENT, res);
+        res = dir[0].open(&fs, "burito");
+        TEST_ASSERT_NOT_EQUAL(0, res);
+        res = file[0].open(&fs, "tomato", O_RDONLY);
+        TEST_ASSERT_EQUAL(-ENOENT, res);
+        res = file[0].open(&fs, "potato", O_RDONLY);
+        TEST_ASSERT_NOT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_nested_directories() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("potato/baked", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("potato/sweet", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("potato/fried", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "/");
+        TEST_ASSERT_EQUAL(0, res);
+        char *dir_list[] = {"potato", "baked", "sweet", "fried", ".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_multi_block_directory() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("cactus", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        for (int i = 0; i < 128; i++) {
+            sprintf((char*)buffer, "cactus/test%d", i);
+            res = fs.mkdir((char*)buffer, 0777);
+            TEST_ASSERT_EQUAL(0, res);
+        }
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "cactus");
+        TEST_ASSERT_EQUAL(0, res);
+
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        char *dir_list[] = {".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+#endif
+
+        for (int i = 0; i < 128; i++) {
+            sprintf((char*)buffer, "test%d", i);
+            res = dir[0].read(&ent);
+            TEST_ASSERT_EQUAL(1, res);
+            res = strcmp(ent.d_name, (char*)buffer);
+            TEST_ASSERT_EQUAL(0, res);
+        }
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_directory_remove() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("potato");
+        TEST_ASSERT_NOT_EQUAL(0, res);
+        res = fs.remove("potato/sweet");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("potato/baked");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("potato/fried");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "potato");
+        TEST_ASSERT_EQUAL(0, res);
+
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        char *dir_list[] = {".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+#endif
+
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("potato");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "/");
+        TEST_ASSERT_EQUAL(0, res);
+        char *dir_list[] = {"burito", "cactus", ".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_directory_rename() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("coldpotato", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("coldpotato/baked", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("coldpotato/sweet", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("coldpotato/fried", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("coldpotato", "hotpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "hotpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        char *dir_list[] = {"baked", "sweet", "fried", ".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("warmpotato", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("warmpotato/mushy", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("hotpotato", "warmpotato");
+        TEST_ASSERT_NOT_EQUAL(0, res);
+        res = fs.remove("warmpotato/mushy");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("warmpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("hotpotato", "warmpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "warmpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        char *dir_list[] = {"baked", "sweet", "fried", ".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("coldpotato", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("warmpotato/baked", "coldpotato/baked");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("warmpotato/sweet", "coldpotato/sweet");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.rename("warmpotato/fried", "coldpotato/fried");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.remove("coldpotato");
+        TEST_ASSERT_NOT_EQUAL(0, res);
+        res = fs.remove("warmpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "coldpotato");
+        TEST_ASSERT_EQUAL(0, res);
+        char *dir_list[] = {"baked", "sweet", "fried", ".", ".."};
+        dir_file_check(dir_list, (sizeof(dir_list)/sizeof(dir_list[0])));
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+
+
+// test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(MBED_TEST_TIMEOUT, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Directory tests", test_directory_tests),
+    Case("Root directory", test_root_directory),
+    Case("Directory creation", test_directory_creation),
+    Case("File creation", test_file_creation),
+    Case("Directory iteration", test_directory_iteration),
+    Case("Directory failures", test_directory_failures),
+    Case("Nested directories", test_nested_directories),
+    Case("Multi-block directory", test_multi_block_directory),
+    Case("Directory remove", test_directory_remove),
+    Case("Directory rename", test_directory_rename),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}
diff --git a/TESTS/filesystem/files/main.cpp b/TESTS/filesystem/files/main.cpp
new file mode 100644
index 0000000000..a50782c3a4
--- /dev/null
+++ b/TESTS/filesystem/files/main.cpp
@@ -0,0 +1,314 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+#include <stdlib.h>
+#include <errno.h>
+
+using namespace utest::v1;
+
+// test configuration
+#ifndef MBED_TEST_FILESYSTEM
+#define MBED_TEST_FILESYSTEM FATFileSystem
+#endif
+
+#ifndef MBED_TEST_FILESYSTEM_DECL
+#define MBED_TEST_FILESYSTEM_DECL MBED_TEST_FILESYSTEM fs("fs")
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE
+#define MBED_TEST_BLOCKDEVICE SDBlockDevice
+#define MBED_TEST_BLOCKDEVICE_DECL SDBlockDevice bd(MBED_CONF_SD_SPI_MOSI, MBED_CONF_SD_SPI_MISO, MBED_CONF_SD_SPI_CLK, MBED_CONF_SD_SPI_CS);
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE_DECL
+#define MBED_TEST_BLOCKDEVICE_DECL MBED_TEST_BLOCKDEVICE bd
+#endif
+
+#ifndef MBED_TEST_FILES
+#define MBED_TEST_FILES 4
+#endif
+
+#ifndef MBED_TEST_DIRS
+#define MBED_TEST_DIRS 4
+#endif
+
+#ifndef MBED_TEST_BUFFER
+#define MBED_TEST_BUFFER 8192
+#endif
+
+#ifndef MBED_TEST_TIMEOUT
+#define MBED_TEST_TIMEOUT 120
+#endif
+
+
+// declarations
+#define STRINGIZE(x) STRINGIZE2(x)
+#define STRINGIZE2(x) #x
+#define INCLUDE(x) STRINGIZE(x.h)
+
+#include INCLUDE(MBED_TEST_FILESYSTEM)
+#include INCLUDE(MBED_TEST_BLOCKDEVICE)
+
+MBED_TEST_FILESYSTEM_DECL;
+MBED_TEST_BLOCKDEVICE_DECL;
+
+Dir dir[MBED_TEST_DIRS];
+File file[MBED_TEST_FILES];
+DIR *dd[MBED_TEST_DIRS];
+FILE *fd[MBED_TEST_FILES];
+struct dirent ent;
+struct dirent *ed;
+size_t size;
+uint8_t buffer[MBED_TEST_BUFFER];
+uint8_t rbuffer[MBED_TEST_BUFFER];
+uint8_t wbuffer[MBED_TEST_BUFFER];
+
+static char file_counter = 0;
+const char *filenames[] = {"smallavacado", "mediumavacado", "largeavacado",
+                          "blockfile", "bigblockfile", "hello", ".", ".."};
+
+// tests
+
+void test_file_tests() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = MBED_TEST_FILESYSTEM::format(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_simple_file_test() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello", O_WRONLY | O_CREAT);
+        TEST_ASSERT_EQUAL(0, res);
+        size = strlen("Hello World!\n");
+        memcpy(wbuffer, "Hello World!\n", size);
+        res = file[0].write(wbuffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        size = strlen("Hello World!\n");
+        res = file[0].read(rbuffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(rbuffer, wbuffer, size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+template <int file_size, int write_size, int read_size>
+void test_write_file_test() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        size_t size = file_size;
+        size_t chunk = write_size;
+        srand(0);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, filenames[file_counter], O_WRONLY | O_CREAT);
+        TEST_ASSERT_EQUAL(0, res);
+        for (size_t i = 0; i < size; i += chunk) {
+            chunk = (chunk < size - i) ? chunk : size - i;
+            for (size_t b = 0; b < chunk; b++) {
+                buffer[b] = rand() & 0xff;
+            }
+            res = file[0].write(buffer, chunk);
+            TEST_ASSERT_EQUAL(chunk, res);
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        size_t size = file_size;
+        size_t chunk = read_size;
+        srand(0);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, filenames[file_counter], O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        for (size_t i = 0; i < size; i += chunk) {
+            chunk = (chunk < size - i) ? chunk : size - i;
+            res = file[0].read(buffer, chunk);
+            TEST_ASSERT_EQUAL(chunk, res);
+            for (size_t b = 0; b < chunk && i+b < size; b++) {
+                res = buffer[b];
+                TEST_ASSERT_EQUAL(rand() & 0xff, res);
+            }
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    file_counter++;
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_non_overlap_check() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        size_t size = 32;
+        size_t chunk = 29;
+        srand(0);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "smallavacado", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        for (size_t i = 0; i < size; i += chunk) {
+            chunk = (chunk < size - i) ? chunk : size - i;
+            res = file[0].read(buffer, chunk);
+            TEST_ASSERT_EQUAL(chunk, res);
+            for (size_t b = 0; b < chunk && i+b < size; b++) {
+                res = buffer[b];
+                TEST_ASSERT_EQUAL(rand() & 0xff, res);
+            }
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        size_t size = 8192;
+        size_t chunk = 29;
+        srand(0);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "mediumavacado", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        for (size_t i = 0; i < size; i += chunk) {
+            chunk = (chunk < size - i) ? chunk : size - i;
+            res = file[0].read(buffer, chunk);
+            TEST_ASSERT_EQUAL(chunk, res);
+            for (size_t b = 0; b < chunk && i+b < size; b++) {
+                res = buffer[b];
+                TEST_ASSERT_EQUAL(rand() & 0xff, res);
+            }
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    {
+        size_t size = 262144;
+        size_t chunk = 29;
+        srand(0);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "largeavacado", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+        for (size_t i = 0; i < size; i += chunk) {
+            chunk = (chunk < size - i) ? chunk : size - i;
+            res = file[0].read(buffer, chunk);
+            TEST_ASSERT_EQUAL(chunk, res);
+            for (size_t b = 0; b < chunk && i+b < size; b++) {
+                res = buffer[b];
+                TEST_ASSERT_EQUAL(rand() & 0xff, res);
+            }
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_dir_check() {
+
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "/");
+        TEST_ASSERT_EQUAL(0, res);
+        int numFiles = sizeof(filenames)/sizeof(filenames[0]);
+        // Check the filenames in directory
+        while(1) {
+            res = dir[0].read(&ent);
+            if (0 == res) {
+                break;
+            }
+            for (int i=0; i < numFiles ; i++) {
+                res = strcmp(ent.d_name, filenames[i]);
+                if (0 == res) {
+                    res = ent.d_type;
+                    if ((DT_REG != res) && (DT_DIR != res)) {
+                        TEST_ASSERT(1);
+                    }
+                    break;
+                }
+                else if( i == numFiles) {
+                    TEST_ASSERT_EQUAL(0, res);
+                }
+            }
+        }
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+
+// test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(MBED_TEST_TIMEOUT, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("File tests", test_file_tests),
+    Case("Simple file test", test_simple_file_test),
+    Case("Small file test", test_write_file_test<32, 31, 29>),
+    Case("Medium file test", test_write_file_test<8192, 31, 29>),
+    Case("Large file test", test_write_file_test<262144, 31, 29>),
+    Case("Block Size file test", test_write_file_test<9000, 512, 512>),
+    Case("Multiple block size file test", test_write_file_test<26215, MBED_TEST_BUFFER, MBED_TEST_BUFFER>),
+    Case("Non-overlap check", test_non_overlap_check),
+    Case("Dir check", test_dir_check),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}
diff --git a/TESTS/filesystem/fopen/fopen.cpp b/TESTS/filesystem/fopen/fopen.cpp
index b3609aa47c..5f51059ca7 100644
--- a/TESTS/filesystem/fopen/fopen.cpp
+++ b/TESTS/filesystem/fopen/fopen.cpp
@@ -199,8 +199,10 @@ int32_t fsfat_filepath_remove_all(char* filepath)
     pos = fpathbuf + strlen(fpathbuf);
     while (pos != fpathbuf) {
         /* If the remaining file path is the mount point path then finish as the mount point cannot be removed */
-        if (strlen(fpathbuf) == strlen(FSFAT_FOPEN_TEST_MOUNT_PT_PATH) && strncmp(fpathbuf, FSFAT_FOPEN_TEST_MOUNT_PT_PATH, strlen(fpathbuf)) == 0) {
-            break;
+        if (strlen(fpathbuf) == strlen(FSFAT_FOPEN_TEST_MOUNT_PT_PATH)) {
+            if( strncmp(fpathbuf, FSFAT_FOPEN_TEST_MOUNT_PT_PATH, strlen(fpathbuf)) == 0) {
+                break;
+            }
         }
         ret = remove(fpathbuf);
         pos = strrchr(fpathbuf, '/');
@@ -1092,15 +1094,6 @@ control_t fsfat_fopen_test_12(const size_t call_count)
     *pos = '\0';
     dir = opendir(buf);
 
-    dp = readdir(dir);
-    TEST_ASSERT_MESSAGE(dp != 0, "Error: readdir() failed\n");
-    FSFAT_TEST_UTEST_MESSAGE(fsfat_fopen_utest_msg_g, FSFAT_UTEST_MSG_BUF_SIZE, "%s:Error: unexpected object name (name=%s, expected=%s).\n", __func__, dp->d_name, ".");
-    TEST_ASSERT_MESSAGE(strncmp(dp->d_name, ".", strlen(".")) == 0, fsfat_fopen_utest_msg_g);
-    dp = readdir(dir);
-    TEST_ASSERT_MESSAGE(dp != 0, "Error: readdir() failed\n");
-    FSFAT_TEST_UTEST_MESSAGE(fsfat_fopen_utest_msg_g, FSFAT_UTEST_MSG_BUF_SIZE, "%s:Error: unexpected object name (name=%s, expected=%s).\n", __func__, dp->d_name, "..");
-    TEST_ASSERT_MESSAGE(strncmp(dp->d_name, "..", strlen("..")) == 0, fsfat_fopen_utest_msg_g);
-
     while ((dp = readdir(dir)) != NULL) {
         FSFAT_DBGLOG("%s: filename: \"%s\"\n", __func__, dp->d_name);
         TEST_ASSERT_MESSAGE(dp != 0, "Error: readdir() failed\n");
diff --git a/TESTS/filesystem/parallel/main.cpp b/TESTS/filesystem/parallel/main.cpp
new file mode 100644
index 0000000000..9c53afd58a
--- /dev/null
+++ b/TESTS/filesystem/parallel/main.cpp
@@ -0,0 +1,184 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+#include <stdlib.h>
+#include <errno.h>
+
+using namespace utest::v1;
+
+// test configuration
+#ifndef MBED_TEST_FILESYSTEM
+#define MBED_TEST_FILESYSTEM FATFileSystem
+#endif
+
+#ifndef MBED_TEST_FILESYSTEM_DECL
+#define MBED_TEST_FILESYSTEM_DECL MBED_TEST_FILESYSTEM fs("fs")
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE
+#define MBED_TEST_BLOCKDEVICE SDBlockDevice
+#define MBED_TEST_BLOCKDEVICE_DECL SDBlockDevice bd(MBED_CONF_SD_SPI_MOSI, MBED_CONF_SD_SPI_MISO, MBED_CONF_SD_SPI_CLK, MBED_CONF_SD_SPI_CS);
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE_DECL
+#define MBED_TEST_BLOCKDEVICE_DECL MBED_TEST_BLOCKDEVICE bd
+#endif
+
+#ifndef MBED_TEST_FILES
+#define MBED_TEST_FILES 4
+#endif
+
+#ifndef MBED_TEST_DIRS
+#define MBED_TEST_DIRS 4
+#endif
+
+#ifndef MBED_TEST_BUFFER
+#define MBED_TEST_BUFFER 512
+#endif
+
+#ifndef MBED_TEST_TIMEOUT
+#define MBED_TEST_TIMEOUT 120
+#endif
+
+#ifndef MBED_THREAD_COUNT
+#define MBED_THREAD_COUNT    MBED_TEST_FILES
+#endif
+
+// declarations
+#define STRINGIZE(x) STRINGIZE2(x)
+#define STRINGIZE2(x) #x
+#define INCLUDE(x) STRINGIZE(x.h)
+
+#include INCLUDE(MBED_TEST_FILESYSTEM)
+#include INCLUDE(MBED_TEST_BLOCKDEVICE)
+
+MBED_TEST_FILESYSTEM_DECL;
+MBED_TEST_BLOCKDEVICE_DECL;
+
+Dir dir[MBED_TEST_DIRS];
+File file[MBED_TEST_FILES];
+DIR *dd[MBED_TEST_DIRS];
+FILE *fd[MBED_TEST_FILES];
+struct dirent ent;
+struct dirent *ed;
+
+volatile bool count_done = 0;
+
+// tests
+
+void test_file_tests() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = MBED_TEST_FILESYSTEM::format(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void write_file_data (char count) {
+
+    char filename[10];
+    uint8_t wbuffer[MBED_TEST_BUFFER];
+    int res;
+
+    sprintf(filename, "%s%d", "data", count);
+    res = file[count].open(&fs, filename, O_WRONLY | O_CREAT);
+    TEST_ASSERT_EQUAL(0, res);
+    
+    char letter = 'A'+ count;
+    for (uint32_t i = 0; i < MBED_TEST_BUFFER; i++) {
+        wbuffer[i] = letter++;
+        if ('z' == letter) {
+            letter = 'A' + count;
+        }    
+    }
+    
+    for (uint32_t i = 0; i < 5; i++) {
+        res = file[count].write(wbuffer, MBED_TEST_BUFFER);
+        TEST_ASSERT_EQUAL(MBED_TEST_BUFFER, res);
+    }
+
+    res = file[count].close();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void read_file_data (char count) {
+    char filename[10];
+    uint8_t rbuffer[MBED_TEST_BUFFER];
+    int res;
+
+    sprintf(filename, "%s%d", "data", count);
+    res = file[count].open(&fs, filename, O_RDONLY);
+    TEST_ASSERT_EQUAL(0, res);
+
+    for (uint32_t i = 0; i < 5; i++) {
+        res = file[count].read(rbuffer, MBED_TEST_BUFFER);
+        TEST_ASSERT_EQUAL(MBED_TEST_BUFFER, res);
+        char letter = 'A' + count;
+        for (uint32_t i = 0; i < MBED_TEST_BUFFER; i++) {
+            res = rbuffer[i];
+            TEST_ASSERT_EQUAL(letter++, res);
+            if ('z' == letter) {
+                letter = 'A' + count;
+            }
+        }
+    }
+
+    res = file[count].close();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_thread_access_test() {
+    
+    Thread *data[MBED_THREAD_COUNT];    
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+    res = fs.mount(&bd);
+    TEST_ASSERT_EQUAL(0, res);
+    
+    // Write threads in parallel
+    for (char thread_count = 0; thread_count < MBED_THREAD_COUNT; thread_count++) {
+        data[thread_count] = new Thread(osPriorityNormal);
+        data[thread_count]->start(callback((void(*)(void*))write_file_data, (void*)thread_count));
+    }
+    
+    // Wait for write thread to join before creating read thread
+    for (char thread_count = 0; thread_count < MBED_THREAD_COUNT; thread_count++) {
+        data[thread_count]->join();
+        delete data[thread_count];
+        data[thread_count] = new Thread(osPriorityNormal);
+        data[thread_count]->start(callback((void(*)(void*))read_file_data, (void*)thread_count));
+    }
+    
+    // Wait for read threads to join
+    for (char thread_count = 0; thread_count < MBED_THREAD_COUNT; thread_count++) {
+        data[thread_count]->join();
+        delete data[thread_count];
+    }
+    res = fs.unmount();
+    TEST_ASSERT_EQUAL(0, res);
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+// test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(MBED_TEST_TIMEOUT, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("File tests", test_file_tests),
+    Case("Filesystem access from multiple threads", test_thread_access_test),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}
diff --git a/TESTS/filesystem/seek/main.cpp b/TESTS/filesystem/seek/main.cpp
new file mode 100644
index 0000000000..bccc170c8c
--- /dev/null
+++ b/TESTS/filesystem/seek/main.cpp
@@ -0,0 +1,629 @@
+#include "mbed.h"
+#include "greentea-client/test_env.h"
+#include "unity.h"
+#include "utest.h"
+#include <stdlib.h>
+#include <errno.h>
+
+using namespace utest::v1;
+
+// test configuration
+#ifndef MBED_TEST_FILESYSTEM
+#define MBED_TEST_FILESYSTEM FATFileSystem
+#endif
+
+#ifndef MBED_TEST_FILESYSTEM_DECL
+#define MBED_TEST_FILESYSTEM_DECL MBED_TEST_FILESYSTEM fs("fs")
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE
+#define MBED_TEST_BLOCKDEVICE SDBlockDevice
+#define MBED_TEST_BLOCKDEVICE_DECL SDBlockDevice bd(MBED_CONF_SD_SPI_MOSI, MBED_CONF_SD_SPI_MISO, MBED_CONF_SD_SPI_CLK, MBED_CONF_SD_SPI_CS);
+#endif
+
+#ifndef MBED_TEST_BLOCKDEVICE_DECL
+#define MBED_TEST_BLOCKDEVICE_DECL MBED_TEST_BLOCKDEVICE bd
+#endif
+
+#ifndef MBED_TEST_FILES
+#define MBED_TEST_FILES 4
+#endif
+
+#ifndef MBED_TEST_DIRS
+#define MBED_TEST_DIRS 4
+#endif
+
+#ifndef MBED_TEST_BUFFER
+#define MBED_TEST_BUFFER 8192
+#endif
+
+#ifndef MBED_TEST_TIMEOUT
+#define MBED_TEST_TIMEOUT 120
+#endif
+
+
+// declarations
+#define STRINGIZE(x) STRINGIZE2(x)
+#define STRINGIZE2(x) #x
+#define INCLUDE(x) STRINGIZE(x.h)
+
+#include INCLUDE(MBED_TEST_FILESYSTEM)
+#include INCLUDE(MBED_TEST_BLOCKDEVICE)
+
+MBED_TEST_FILESYSTEM_DECL;
+MBED_TEST_BLOCKDEVICE_DECL;
+
+Dir dir[MBED_TEST_DIRS];
+File file[MBED_TEST_FILES];
+DIR *dd[MBED_TEST_DIRS];
+FILE *fd[MBED_TEST_FILES];
+struct dirent ent;
+struct dirent *ed;
+size_t size;
+uint8_t buffer[MBED_TEST_BUFFER];
+uint8_t rbuffer[MBED_TEST_BUFFER];
+uint8_t wbuffer[MBED_TEST_BUFFER];
+
+
+// tests
+
+void test_seek_tests() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = MBED_TEST_FILESYSTEM::format(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.mkdir("hello", 0777);
+        TEST_ASSERT_EQUAL(0, res);
+        for (int i = 0; i < 132; i++) {
+            sprintf((char*)buffer, "hello/kitty%d", i);
+            res = file[0].open(&fs, (char*)buffer,
+                    O_WRONLY | O_CREAT | O_APPEND);
+            TEST_ASSERT_EQUAL(0, res);
+    
+            size = strlen("kittycatcat");
+            memcpy(buffer, "kittycatcat", size);
+            for (int j = 0; j < 132; j++) {
+                file[0].write(buffer, size);
+            }
+            res = file[0].close();
+            TEST_ASSERT_EQUAL(0, res);
+        }
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_simple_dir_seek() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "hello");
+        TEST_ASSERT_EQUAL(0, res);
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, ".");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, "..");
+        TEST_ASSERT_EQUAL(0, res);
+#endif
+
+        off_t pos;
+        int i;
+        for (i = 0; i < 4; i++) {
+            sprintf((char*)buffer, "kitty%d", i);
+            res = dir[0].read(&ent);
+            TEST_ASSERT_EQUAL(1, res);
+            res = strcmp(ent.d_name, (char*)buffer);
+            TEST_ASSERT_EQUAL(0, res);
+            pos = dir[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+    
+        dir[0].seek(pos);
+        sprintf((char*)buffer, "kitty%d", i);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        dir[0].rewind();
+        sprintf((char*)buffer, "kitty%d", 0);
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, ".");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, "..");
+        TEST_ASSERT_EQUAL(0, res);
+#endif
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        dir[0].seek(pos);
+        sprintf((char*)buffer, "kitty%d", i);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_large_dir_seek() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].open(&fs, "hello");
+        TEST_ASSERT_EQUAL(0, res);
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, ".");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, "..");
+        TEST_ASSERT_EQUAL(0, res);
+#endif
+
+        off_t pos;
+        int i;
+        for (i = 0; i < 128; i++) {
+            sprintf((char*)buffer, "kitty%d", i);
+            res = dir[0].read(&ent);
+            TEST_ASSERT_EQUAL(1, res);
+            res = strcmp(ent.d_name, (char*)buffer);
+            TEST_ASSERT_EQUAL(0, res);
+            pos = dir[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+    
+        dir[0].seek(pos);
+        sprintf((char*)buffer, "kitty%d", i);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        dir[0].rewind();
+        sprintf((char*)buffer, "kitty%d", 0);
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, ".");
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, "..");
+        TEST_ASSERT_EQUAL(0, res);
+#endif
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        dir[0].seek(pos);
+        sprintf((char*)buffer, "kitty%d", i);
+        res = dir[0].read(&ent);
+        TEST_ASSERT_EQUAL(1, res);
+        res = strcmp(ent.d_name, (char*)buffer);
+        TEST_ASSERT_EQUAL(0, res);
+        res = dir[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_simple_file_seek() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        off_t pos;
+        size = strlen("kittycatcat");
+        for (int i = 0; i < 4; i++) {
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = memcmp(buffer, "kittycatcat", size);
+            TEST_ASSERT_EQUAL(0, res);
+            pos = file[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        file[0].rewind();
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_CUR);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_END) >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size_t size = file[0].size();
+        res = file[0].seek(0, SEEK_CUR);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_large_file_seek() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDONLY);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        off_t pos;
+        size = strlen("kittycatcat");
+        for (int i = 0; i < 128; i++) {
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = memcmp(buffer, "kittycatcat", size);
+            TEST_ASSERT_EQUAL(0, res);
+            pos = file[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        file[0].rewind();
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_CUR);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_END) >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size_t size = file[0].size();
+        res = file[0].seek(0, SEEK_CUR);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_simple_file_seek_and_write() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDWR);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        off_t pos;
+        size = strlen("kittycatcat");
+        for (int i = 0; i < 4; i++) {
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = memcmp(buffer, "kittycatcat", size);
+            TEST_ASSERT_EQUAL(0, res);
+            pos = file[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+    
+        memcpy(buffer, "doggodogdog", size);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].write(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "doggodogdog", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        file[0].rewind();
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "doggodogdog", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_END) >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size_t size = file[0].size();
+        res = file[0].seek(0, SEEK_CUR);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_large_file_seek_and_write() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDWR);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        off_t pos;
+        size = strlen("kittycatcat");
+        for (int i = 0; i < 128; i++) {
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            if (i != 4) {
+                res = memcmp(buffer, "kittycatcat", size);
+                TEST_ASSERT_EQUAL(0, res);
+            }
+            pos = file[0].tell();
+        }
+        res = pos >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+    
+        memcpy(buffer, "doggodogdog", size);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].write(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "doggodogdog", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        file[0].rewind();
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(pos, SEEK_SET);
+        TEST_ASSERT_EQUAL(pos, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "doggodogdog", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(-size, SEEK_END) >= 0;
+        TEST_ASSERT_EQUAL(1, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "kittycatcat", size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size_t size = file[0].size();
+        res = file[0].seek(0, SEEK_CUR);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_boundary_seek_and_write() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDWR);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size = strlen("hedgehoghog");
+        const off_t offsets[] = {512, 1020, 513, 1021, 511, 1019};
+    
+        for (int i = 0; i < sizeof(offsets) / sizeof(offsets[0]); i++) {
+            off_t off = offsets[i];
+            memcpy(buffer, "hedgehoghog", size);
+            res = file[0].seek(off, SEEK_SET);
+            TEST_ASSERT_EQUAL(off, res);
+            res = file[0].write(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = file[0].seek(off, SEEK_SET);
+            TEST_ASSERT_EQUAL(off, res);
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = memcmp(buffer, "hedgehoghog", size);
+            TEST_ASSERT_EQUAL(0, res);
+            res = file[0].seek(0, SEEK_SET);
+            TEST_ASSERT_EQUAL(0, res);
+            res = file[0].read(buffer, size);
+            TEST_ASSERT_EQUAL(size, res);
+            res = memcmp(buffer, "kittycatcat", size);
+            TEST_ASSERT_EQUAL(0, res);
+            res = file[0].sync();
+            TEST_ASSERT_EQUAL(0, res);
+        }
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+void test_out_of_bounds_seek() {
+    int res = bd.init();
+    TEST_ASSERT_EQUAL(0, res);
+
+    {
+        res = fs.mount(&bd);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].open(&fs, "hello/kitty42", O_RDWR);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        size = strlen("kittycatcat");
+        res = file[0].size();
+        TEST_ASSERT_EQUAL(132*size, res);
+        res = file[0].seek((132+4)*size,
+                SEEK_SET);
+        TEST_ASSERT_EQUAL((132+4)*size, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(0, res);
+    
+        memcpy(buffer, "porcupineee", size);
+        res = file[0].write(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = file[0].seek((132+4)*size,
+                SEEK_SET);
+        TEST_ASSERT_EQUAL((132+4)*size, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+        res = memcmp(buffer, "porcupineee", size);
+        TEST_ASSERT_EQUAL(0, res);
+        res = file[0].seek(132*size,
+                SEEK_SET);
+        TEST_ASSERT_EQUAL(132*size, res);
+        res = file[0].read(buffer, size);
+        TEST_ASSERT_EQUAL(size, res);
+#if (MBED_TEST_FILESYSTEM != FATFileSystem)
+        // FatFs does not guarantee empty expanded buffer
+        res = memcmp(buffer, "\0\0\0\0\0\0\0\0\0\0\0", size);
+        TEST_ASSERT_EQUAL(0, res);
+#endif
+        res = file[0].close();
+        TEST_ASSERT_EQUAL(0, res);
+        res = fs.unmount();
+        TEST_ASSERT_EQUAL(0, res);
+    }
+
+    res = bd.deinit();
+    TEST_ASSERT_EQUAL(0, res);
+}
+
+
+
+// test setup
+utest::v1::status_t test_setup(const size_t number_of_cases) {
+    GREENTEA_SETUP(MBED_TEST_TIMEOUT, "default_auto");
+    return verbose_test_setup_handler(number_of_cases);
+}
+
+Case cases[] = {
+    Case("Seek tests", test_seek_tests),
+    Case("Simple dir seek", test_simple_dir_seek),
+    Case("Large dir seek", test_large_dir_seek),
+    Case("Simple file seek", test_simple_file_seek),
+    Case("Large file seek", test_large_file_seek),
+    Case("Simple file seek and write", test_simple_file_seek_and_write),
+    Case("Large file seek and write", test_large_file_seek_and_write),
+    Case("Boundary seek and write", test_boundary_seek_and_write),
+    Case("Out-of-bounds seek", test_out_of_bounds_seek),
+};
+
+Specification specification(test_setup, cases);
+
+int main() {
+    return !Harness::run(specification);
+}