Fix the append test by writing, closing, then seeking and writing

This fixes the append test to correctly run by writing, closing the
file, opening it again and seeking, then writing again.  This will
result in a typical append.

src/cc/qfsc/test-qfsc.c

@@ -33,7 +33,7 @@ static char mbuf[4096];
 
 static int tests_run;
 static char* metaserver_host = "localhost";
-static int metaserver_port = 10000;
+static int metaserver_port = 20000;
 
 // Global file system and file descriptor under test.
 struct QFS* qfs;
@@ -191,11 +191,6 @@ static char* test_qfs_stat() {
   return 0;
 }
 
-static char* test_qfs_stat_multiple() {
-  struct qfs_attr attr;
-
-}
-
 static char* test_qfs_create() {
   check_qfs_call(fd = qfs_create(qfs, "/unit-test/file"));
 
@@ -344,16 +339,23 @@ static char* test_qfs_get_data_locations() {
   return 0;
 }
 
+// Append to a file by Writing, closing, seeking, and then writing again. This
+// emulates a typical unix O_APPEND operation without using the flag.
+//
+// Using O_APPEND itself does not produce the same result.  Opening a file with
+// O_APPEND and writing to it will create hole of the appropriate size to make
+// the previous chunk reach the chunksize.  This can be useful as an atomic
+// append, but is not the behavior you'd expect from a normal filesystem.
 static char* test_qfs_append() {
-  char single_byte = 'a';
-  check_qfs_call(qfs_write(qfs, fd, &single_byte, 1));
+  check_qfs_call(qfs_write(qfs, fd, testdata, strlen(testdata)));
   check_qfs_call(qfs_sync(qfs, fd));
 
   check_qfs_call(qfs_close(qfs, fd));
 
-  // Now write the same data again (appending this time)
-  check_qfs_call(fd = qfs_open_file(qfs, "/unit-test/file", O_WRONLY|O_APPEND, 0, ""));
-  check_qfs_call(qfs_write(qfs, fd, &single_byte, 1));
+  // Now write the same data again to the end of the file by seeking
+  check_qfs_call(fd = qfs_open_file(qfs, "/unit-test/file", O_WRONLY, 0, ""));
+  check_qfs_call(qfs_seek(qfs, fd, 0, SEEK_END));
+  check_qfs_call(qfs_write(qfs, fd, testdata, strlen(testdata)));
   check_qfs_call(qfs_sync(qfs, fd));
 
   // Check that the file has the correct size
@@ -364,18 +366,19 @@ static char* test_qfs_append() {
   struct qfs_attr attr;
   check_qfs_call(qfs_stat(qfs, "/unit-test/file", &attr));
 
-  // This check for file size fails.
-  /* check(attr.size == 2, */
-  /*   "file size should be correct: %li != %d", */
-  /*   (long)attr.size, 2); */
-  ssize_t chunk_size = qfs_get_chunksize(qfs, "/unit-test/file");
-  printf("Block size is: %li\n", (long)chunk_size);
-  printf("Size of appended file is: %li\n", (long)attr.size);
+  int expected_len = strlen(testdata) * 2;
+  check(attr.size == expected_len,
+	"file size should be correct: %li != %d",
+	(long)attr.size, expected_len);
 
-  // Try and read the file
-  char buf[2];
-  check_qfs_call(qfs_read(qfs, fd, buf, 2));
-  check(strcmp("aa", buf) == 0, "The contents of the file are not correct");
+  // Generate the string consisting of the testdata twice
+  char expected_str[expected_len];
+  strcpy(expected_str, testdata);
+  strcat(expected_str, testdata);
+
+  char buf[expected_len];
+  check_qfs_call(qfs_read(qfs, fd, buf, expected_len));
+  check(strncmp(expected_str, buf, expected_len) == 0, "The contents of the file are not correct:\n\tExpected: %s\n\tActual: %s", expected_str, buf);
 
   return 0;
 }
@@ -407,10 +410,10 @@ static char * all_tests() {
   run(test_qfs_close);
   run(test_qfs_open);
   run(test_qfs_pread);
+  run(test_qfs_get_data_locations);
   run(test_qfs_close);
   run(test_qfs_open_file);
   run(test_qfs_append);
-  run(test_qfs_get_data_locations);
   run(test_qfs_cleanup);
   run(test_qfs_release);
   return 0;