improve 9.14 test code

Author: DreamAndDead

chapter9/code/.gitignore

@@ -1,4 +1,5 @@
 9.14
 9.17
 9.18
+hello.txt
 

chapter9/code/9.14.c

@@ -2,9 +2,29 @@
  * 9.14.c
  */
 #include <stdio.h>
+#include <assert.h>
 #include "vm/csapp.h"
 
+int test(char* filename, char* content) {
+  int fd;
+  char buf[20];
+  fd = Open(filename, O_RDONLY, 0);
+  Read(fd, buf, strlen(content));
+  return !strncmp(buf, content, strlen(content));
+}
+
+int touch(char* filename, char* content) {
+  int fd;
+  umask(DEF_UMASK);
+  fd = Open(filename, O_WRONLY|O_CREAT|O_TRUNC, DEF_MODE);
+  Write(fd, content, strlen(content));
+  Close(fd);
+}
+
 int main(int argc, char* argv[]) {
+  touch("hello.txt", "Hello, world!");
+  assert(test("hello.txt", "Hello, world!"));
+
   struct stat stat;
   int fd;
   char* bufp;
@@ -18,6 +38,7 @@ int main(int argc, char* argv[]) {
   *bufp = 'J';
   Munmap(bufp, size);
 
+  assert(test("hello.txt", "Jello, world!"));
   return 0;
 }
 

chapter9/code/hello.txt

@@ -23,7 +23,7 @@ test way:
 |9.11|----|----|
 |9.12|----|----|
 |9.13|----|----|
-|9.14|9.14.c|check hello.txt|
+|9.14|9.14.c|assert|
 |9.15|----|----|
 |9.16|----|----|
 |9.17|vm/(mm.9.17, 9.17.c)|malloc and free|

chapter9/index.md

@@ -11,7 +11,7 @@
 |6|----|----|
 |7|----|----|
 |8|----|----|
-|9|test 9.14, 9.17, 9.18; more detailed reason for 9.19; 9.20 is awful, sub with more professional way(such as segrated fit method) |ing|
+|9|test 9.17, 9.18; more detailed reason for 9.19; 9.20 is awful, sub with more professional way(such as segrated fit method) |ing|
 |10|----|----|
 |11|----|----|
 |12|----|----|