X-Git-Url: http://git.scottworley.com/overonion/blobdiff_plain/a99e77b43df141c988b52e663d64d40e79f11895..2377b838ff45bc3407e0c65028eac858c47c9d4e:/reverse_test.c

diff --git a/reverse_test.c b/reverse_test.c
index 512edaa..30aff32 100644
--- a/reverse_test.c
+++ b/reverse_test.c
@@ -9,6 +9,8 @@
 
 static const char test_file[] = "reverse.c";
 
+/* Reverse input_file.  Dump the result in a temporary file.  Return the temp
+ * file's name.  The caller must free the filename. */
 char* reverse_to_temp_file(const char* input_file) {
   char* temp_filename = strdup("/tmp/reverse_test.XXXXXX");
   int fd = mkstemp(temp_filename);
@@ -20,20 +22,19 @@ char* reverse_to_temp_file(const char* input_file) {
   return temp_filename;
 }
 
-void test_reverse_twice_is_the_same() {
-  char* intermediate = reverse_to_temp_file(test_file);
-  char* back_to_normal = reverse_to_temp_file(intermediate);
-
-  FILE* f1 = fopen(test_file, "r");
-  if (f1 == NULL) err(EX_IOERR, "Couldn't open test file");
-  FILE* f2 = fopen(back_to_normal, "r");
-  if (f2 == NULL) err(EX_IOERR, "Couldn't open twice-reversed temp file");
+/* Compare the contents of two files.  Terminate with a diagnostic if they
+ * differ. */
+void compare(const char* filename1, const char* filename2) {
+  FILE* f1 = fopen(filename1, "r");
+  if (f1 == NULL) err(EX_IOERR, "Couldn't open file %s", filename1);
+  FILE* f2 = fopen(filename2, "r");
+  if (f2 == NULL) err(EX_IOERR, "Couldn't open file %s", filename2);
 
   for (int pos = 0; ; pos++) {
     int c1 = fgetc(f1);
     int c2 = fgetc(f2);
-    if (c1 == EOF && ferror(f1)) err(EX_IOERR, "Error reading test file");
-    if (c2 == EOF && ferror(f2)) err(EX_IOERR, "Error reading twice-reversed temp file");
+    if (c1 == EOF && ferror(f1)) err(EX_IOERR, "Error reading file %s", filename1);
+    if (c2 == EOF && ferror(f2)) err(EX_IOERR, "Error reading file %s", filename2);
     if (c1 != c2) {
       errx(EX_SOFTWARE, "Unexpected difference found at offset %d after reversing twice.  "
                         "Expected %d but found %d", pos, c1, c2);
@@ -41,16 +42,55 @@ void test_reverse_twice_is_the_same() {
     if (c1 == EOF) break;
   }
 
-  if (fclose(f1) != 0) err(EX_IOERR, "Couldn't close test file");
-  if (fclose(f2) != 0) err(EX_IOERR, "Couldn't close twice-reversed temp file");
+  if (fclose(f1) != 0) err(EX_IOERR, "Couldn't close file %s", filename1);
+  if (fclose(f2) != 0) err(EX_IOERR, "Couldn't close file %s", filename2);
+}
+
+void test_reverse_twice_from_files_is_the_same() {
+  char* intermediate = reverse_to_temp_file(test_file);
+  char* back_to_normal = reverse_to_temp_file(intermediate);
+
+  compare(test_file, back_to_normal);
+
   if (unlink(intermediate) == -1) err(EX_IOERR, "Couldn't remove intermediate temp file");
   if (unlink(back_to_normal) == -1) err(EX_IOERR, "Couldn't remove twice-reversed temp file");
   free(intermediate);
   free(back_to_normal);
 }
 
+void test_reverse_from_file_then_from_stream_is_the_same() {
+  int pipefd[2];
+  if (pipe(pipefd) == -1) err(EX_OSERR, "Couldn't create pipe");
+
+  pid_t pid = fork();
+  if (pid == -1) err(EX_OSERR, "Couldn't fork");
+  if (pid == 0) {
+    if (close(pipefd[0]) == -1) err(EX_OSERR, "Couldn't close unneeded pipe descriptor");
+    FILE* to_second = fdopen(pipefd[1], "w");
+    if (to_second == NULL) err(EX_IOERR, "Couldn't open pipe for writing");
+    reverse_file(test_file, to_second);
+    exit(0);
+  }
+  if (close(pipefd[1]) == -1) err(EX_OSERR, "Couldn't close unneeded pipe descriptor");
+  FILE* from_first = fdopen(pipefd[0], "r");
+  if (from_first == NULL) err(EX_IOERR, "Couldn't open pipe for reading");
+  char* out_temp_filename = strdup("/tmp/reverse_test.XXXXXX");
+  int out_fd = mkstemp(out_temp_filename);
+  if (out_fd == -1) err(EX_IOERR, "Couldn't make a temporary file");
+  FILE* out_file = fdopen(out_fd, "w");
+  if (out_file == NULL) err(EX_IOERR, "Couldn't open temporary file");
+  reverse_stream(from_first, out_file);
+  if (fclose(out_file) == EOF) err(EX_IOERR, "Couldn't close temporary file");
+
+  compare(test_file, out_temp_filename);
+
+  if (unlink(out_temp_filename) == -1) err(EX_IOERR, "Couldn't remove temp output file");
+  free(out_temp_filename);
+}
+
 int main() {
-  test_reverse_twice_is_the_same();
+  test_reverse_twice_from_files_is_the_same();
+  test_reverse_from_file_then_from_stream_is_the_same();
   puts("PASS");
   return 0;
 }