diff --git a/configure.in b/configure.in
index ae5ed207e..dddc4b8c6 100644
--- a/configure.in
+++ b/configure.in
@@ -931,6 +931,13 @@ if test "x$exec_prefix" = "xNONE"; then
   exec_prefix=$prefix
 fi
 
+if test "x$BUILDDIR" = "x"; then
+  BUILDDIR=`pwd`
+fi
+AC_SUBST(BUILDDIR)
+AH_TEMPLATE([BUILDDIR],[tor's build directory])
+AC_DEFINE_UNQUOTED(BUILDDIR,"$BUILDDIR")
+
 if test "x$CONFDIR" = "x"; then
   CONFDIR=`eval echo $sysconfdir/tor`
 fi
diff --git a/src/test/test-child.c b/src/test/test-child.c
index 100e8c0f3..ca52750c2 100644
--- a/src/test/test-child.c
+++ b/src/test/test-child.c
@@ -9,7 +9,7 @@ main(int argc, char **argv)
 
   fprintf(stdout, "OUT\n");
   fprintf(stderr, "ERR\n");
-  for (i = 0; i < argc; i++)
+  for (i = 1; i < argc; i++)
     fprintf(stdout, "%s\n", argv[i]);
   fprintf(stdout, "DONE\n");
 
diff --git a/src/test/test_util.c b/src/test/test_util.c
index e33a6df88..c4428f5ea 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -1393,8 +1393,8 @@ run_util_spawn_background(const char *argv[], const char *expected_out,
 static void
 test_util_spawn_background_ok(void *ptr)
 {
-  const char *argv[] = {"src/test/test-child", "--test", NULL};
-  const char *expected_out = "OUT\nsrc/test/test-child\n--test\nDONE\n";
+  const char *argv[] = {BUILDDIR "/src/test/test-child", "--test", NULL};
+  const char *expected_out = "OUT\n--test\nDONE\n";
   const char *expected_err = "ERR\n";
 
   (void)ptr;
@@ -1406,7 +1406,7 @@ test_util_spawn_background_ok(void *ptr)
 static void
 test_util_spawn_background_fail(void *ptr)
 {
-  const char *argv[] = {"src/test/no-such-file", "--test", NULL};
+  const char *argv[] = {BUILDDIR "/src/test/no-such-file", "--test", NULL};
   const char *expected_out = "ERR: Failed to spawn background process "
                              "- code          9/2\n";
   const char *expected_err = "";