Accept a test data file as a command line argument

diff --git a/reverse_test.c b/reverse_test.c
index 0b82f19af270ad0150a5f51794f0d00ccea0d46d..46c7a97c40cc1884eee448356f632b0ea4b38a2c 100644 (file)
--- a/reverse_test.c
+++ b/reverse_test.c
@@ -8,8 +8,6 @@
 #include <sysexits.h>
 #include <unistd.h>
 
-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) {
@@ -45,11 +43,11 @@ void compare(const char* filename1, const char* filename2) {
   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);
+void test_reverse_twice_from_files_is_the_same(const char* test_filename) {
+  char* intermediate = reverse_to_temp_file(test_filename);
   char* back_to_normal = reverse_to_temp_file(intermediate);
 
-  compare(test_file, back_to_normal);
+  compare(test_filename, 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");
@@ -57,7 +55,7 @@ void test_reverse_twice_from_files_is_the_same() {
   free(back_to_normal);
 }
 
-void test_reverse_from_file_then_from_stream_is_the_same() {
+void test_reverse_from_file_then_from_stream_is_the_same(const char* test_filename) {
   int pipefd[2];
   if (pipe(pipefd) == -1) err(EX_OSERR, "Couldn't create pipe");
 
@@ -67,7 +65,7 @@ void test_reverse_from_file_then_from_stream_is_the_same() {
     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);
+    reverse_file(test_filename, to_second);
     exit(0);
   }
   if (close(pipefd[1]) == -1) err(EX_OSERR, "Couldn't close unneeded pipe descriptor");
@@ -79,15 +77,23 @@ void test_reverse_from_file_then_from_stream_is_the_same() {
   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);
+  compare(test_filename, 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_from_files_is_the_same();
-  test_reverse_from_file_then_from_stream_is_the_same();
+int main(int argc, char** argv) {
+  char* test_filename = "reverse.c";
+  if (argc > 2) {
+    errx(EX_USAGE, "usage: reverse_test [datafile]");
+  } else if (argc == 2) {
+    test_filename = argv[1];
+  }
+
+  test_reverse_twice_from_files_is_the_same(test_filename);
+  test_reverse_from_file_then_from_stream_is_the_same(test_filename);
+
   puts("PASS");
   return 0;
 }