diff --git a/src/test/test_util.c b/src/test/test_util.c
index cc3a03f84f..1734108635 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -19,114 +19,71 @@
 #endif
 
 static void
-test_util_read_file_fifo_tiny_limit(void *arg)
+test_util_read_until_eof_impl(const char *fname, size_t file_len,
+                              size_t read_limit)
 {
-#ifndef _WIN32
   char *fifo_name = NULL;
+  char *test_str = NULL;
   char *str = NULL;
+  size_t sz = 9999999;
   int fd = -1;
-  int read_fd = -1;
-  size_t sz;
-  (void)arg;
+  int r;
 
-  fifo_name = tor_strdup(get_fname("tor_test_fifo_tiny"));
-  fd = open(fifo_name, O_WRONLY | O_CREAT, 0600);
-  test_neq(fd, -1);
-  test_eq(write(fd, "short", 6), 6);
+  fifo_name = tor_strdup(get_fname(fname));
+  test_str = tor_malloc(file_len);
+  crypto_rand(test_str, file_len);
+
+  r = write_bytes_to_file(fifo_name, test_str, file_len, 1);
+  tt_int_op(r, ==, 0);
+
+  fd = open(fifo_name, O_RDONLY|O_BINARY);
+  tt_int_op(fd, >=, 0);
+  str = read_file_to_str_until_eof(fd, read_limit, &sz);
   close(fd);
+  tt_assert(str != NULL);
 
-  // purposely set limit shorter than what we wrote to the FIFO to
-  // test the maximum, and that it puts the NUL in the right spot
+  if (read_limit < file_len)
+    tt_int_op(sz, ==, read_limit);
+  else
+    tt_int_op(sz, ==, file_len);
 
-  read_fd = open(fifo_name, O_RDONLY);
-  str = read_file_to_str_until_eof(read_fd, 4, &sz);
-  close(read_fd);
-
-  test_eq(str[0], 's');
-  test_eq(str[1], 'h');
-  test_eq(str[2], 'o');
-  test_eq(str[3], 'r');
-  test_eq(str[4], '\0');
+  test_mem_op(test_str, ==, str, sz);
+  test_assert(str[sz] == '\0');
 
  done:
   unlink(fifo_name);
   tor_free(fifo_name);
+  tor_free(test_str);
   tor_free(str);
-#endif
 }
 
 static void
-test_util_read_file_fifo_two_loops(void *arg)
+test_util_read_file_eof_tiny_limit(void *arg)
 {
-#ifndef _WIN32
-  char *fifo_name = NULL;
-  char *str = NULL;
-  char data[2048];
-  int i = 0;
-  int fd = -1;
-  int read_fd = -1;
-  size_t sz;
   (void)arg;
+  // purposely set limit shorter than what we wrote to the FIFO to
+  // test the maximum, and that it puts the NUL in the right spot
 
-  while (i < 2048) {
-    data[i] = (char)(i & 0xff);
-    ++i;
-  }
+  test_util_read_until_eof_impl("tor_test_fifo_tiny", 5, 4);
+}
 
+static void
+test_util_read_file_eof_two_loops(void *arg)
+{
+  (void)arg;
   // write more than 1024 bytes to the FIFO to test two passes through
   // the loop in the method; if the re-alloc size is changed this
   // should be updated as well.
 
-  fifo_name = tor_strdup(get_fname("tor_fifo_test_2k"));
-  fd = open(fifo_name, O_WRONLY | O_CREAT, 0600);
-  test_neq(fd, -1);
-  test_eq(write(fd, data, 2048), 2048);
-  close(fd);
-
-  read_fd = open(fifo_name, O_RDONLY);
-  str = read_file_to_str_until_eof(read_fd, 1024*1024, &sz);
-  close(read_fd);
-
-  for (i = 0; i < 2048; ++i) {
-    test_eq(str[i], (char)(i & 0xff));
-  }
-
- done:
-  unlink(fifo_name);
-  tor_free(fifo_name);
-  tor_free(str);
-#endif
+  test_util_read_until_eof_impl("tor_test_fifo_2k", 2048, 10000);
 }
 
 static void
-test_util_read_file_fifo_zero_bytes(void *arg)
+test_util_read_file_eof_zero_bytes(void *arg)
 {
-#ifndef _WIN32
-  char *fifo_name = NULL;
-  char *str = NULL;
-  int fd = -1;
-  int read_fd = -1;
-  size_t sz;
   (void)arg;
-
-  fifo_name = tor_strdup(get_fname("tor_fifo_test_zero_bytes"));
   // zero-byte fifo
-  fd = open(fifo_name, O_WRONLY | O_CREAT, 0600);
-  test_neq(fd, -1);
-  close(fd);
-
-  read_fd = open(fifo_name, O_RDONLY);
-  str = read_file_to_str_until_eof(read_fd, 1024, &sz);
-  close(read_fd);
-
-  test_neq(str, NULL);
-  test_eq(str[0], '\0');
-
- done:
-  unlink(fifo_name);
-  tor_free(fifo_name);
-  tor_free(str);
-#endif
+  test_util_read_until_eof_impl("tor_test_fifo_empty", 0, 10000);
 }
 
 static void
@@ -3302,9 +3259,9 @@ struct testcase_t util_tests[] = {
   UTIL_TEST(envnames, 0),
   UTIL_TEST(make_environment, 0),
   UTIL_TEST(set_env_var_in_sl, 0),
-  UTIL_TEST(read_file_fifo_tiny_limit, 0),
-  UTIL_TEST(read_file_fifo_two_loops, 0),
-  UTIL_TEST(read_file_fifo_zero_bytes, 0),
+  UTIL_TEST(read_file_eof_tiny_limit, 0),
+  UTIL_TEST(read_file_eof_two_loops, 0),
+  UTIL_TEST(read_file_eof_zero_bytes, 0),
   END_OF_TESTCASES
 };