diff --git a/test/file/main.c b/test/file/main.c
index 5e494153..165c8d4b 100644
--- a/test/file/main.c
+++ b/test/file/main.c
@@ -12,6 +12,7 @@ int main(int argc, const char* argv[]) {
     const char* write_msg = "Hello World\n";
     char read_buf[128] = {0};
 
+    // write
     flags = O_WRONLY | O_CREAT| O_TRUNC;
     mode = 00666;
     if ((fd = open(file_name, flags, mode)) < 0) {
@@ -24,6 +25,7 @@ int main(int argc, const char* argv[]) {
     }
     close(fd);
 
+    // read
     flags = O_RDONLY;
     if ((fd = open(file_name, flags)) < 0) {
         printf("ERROR: failed to open a file for read\n");
@@ -40,14 +42,14 @@ int main(int argc, const char* argv[]) {
         return -1;
     }
 
-
-    flags = O_RDWR;
+	// writev
+    flags = O_WRONLY | O_CREAT| O_TRUNC;
     if ((fd = open(file_name, flags)) < 0) {
-        printf("ERROR: failed to open a file for read and write\n");
+        printf("ERROR: failed to open a file for write\n");
         return -1;
     }
 
-    const char* iov_msg[2] = {"hello ", "world!"};
+    const char* iov_msg[2] = {"hello_", "world!"};
     struct iovec iov[2];
     for(int i=0; i<2; ++i) {
         iov[i].iov_base = (void*)iov_msg[i];
@@ -58,25 +60,49 @@ int main(int argc, const char* argv[]) {
         return -1;
     }
 
-    if ((offset = lseek(fd, 0, SEEK_SET)) != 0) {
+    // pwrite
+	if ((len = pwrite(fd, " ", 1, 5)) != 1) {
+		printf("ERROR: failed to pwrite to the file\n");
+	}
+
+	close(fd);
+
+	flags = O_RDONLY;
+	if ((fd = open(file_name, flags)) < 0) {
+		printf("ERROR: failed to open a file for read\n");
+		return -1;
+	}
+
+	// lseek
+    if ((offset = lseek(fd, 2, SEEK_SET)) != 2) {
         printf("ERROR: failed to lseek the file\n");
         return -1;
     }
 
+    // readv
     iov[0].iov_base = read_buf;
     iov[0].iov_len = 3;
     iov[1].iov_base = read_buf + 5;
     iov[1].iov_len = 20;
-    if ((len = readv(fd, iov, 2)) != 12) {
+    if ((len = readv(fd, iov, 2)) != 10) {
         printf("ERROR: failed to read vectors from the file\n");
         return -1;
     }
 
-    if (memcmp(read_buf, "hel", 3) != 0
-        || memcmp(read_buf + 5, "lo world!", 9) != 0) {
+    if (memcmp(read_buf, "llo", 3) != 0
+        || memcmp(read_buf + 5, " world!", 7) != 0) {
         printf("ERROR: the message read from the file is not as it was written\n");
         return -1;
     }
+
+    // pread
+    if ((len = pread(fd, read_buf, sizeof(read_buf) - 1, 4)) != 8) {
+		printf("ERROR: failed to pread from the file\n");
+	}
+	if (memcmp(read_buf, "o world!", 8) != 0) {
+		printf("ERROR: the message read from the file is not as it was written\n");
+		return -1;
+	}
     close(fd);
 
     printf("File write and read successfully\n");