X-Git-Url: http://git.scottworley.com/overonion/blobdiff_plain/673e2d68a8813804502df1923a6c2f6e727e69a0..f5ec0b4b91687c7a34d4760381f6e7424f981127:/reverse_test.c?ds=sidebyside

diff --git a/reverse_test.c b/reverse_test.c
new file mode 100644
index 0000000..46c7a97
--- /dev/null
+++ b/reverse_test.c
@@ -0,0 +1,99 @@
+#include "reverse_lib.h"
+#include "temp_file.h"
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sysexits.h>
+#include <unistd.h>
+
+/* 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;
+  FILE* f;
+  make_temporary_file(&temp_filename, &f);
+  reverse_file(input_file, f);
+  if (fclose(f) == EOF) err(EX_IOERR, "Couldn't close temporary file");
+  return temp_filename;
+}
+
+/* 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 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);
+    }
+    if (c1 == EOF) break;
+  }
+
+  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(const char* test_filename) {
+  char* intermediate = reverse_to_temp_file(test_filename);
+  char* back_to_normal = reverse_to_temp_file(intermediate);
+
+  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");
+  free(intermediate);
+  free(back_to_normal);
+}
+
+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");
+
+  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_filename, 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;
+  FILE* out_file;
+  make_temporary_file(&out_temp_filename, &out_file);
+  reverse_stream(from_first, out_file);
+  if (fclose(out_file) == EOF) err(EX_IOERR, "Couldn't close temporary file");
+
+  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(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;
+}