diff --git a/tests/test-dup2.c b/tests/test-dup2.c
--- a/tests/test-dup2.c
+++ b/tests/test-dup2.c
@@ -157,8 +157,6 @@ main (void)
       ASSERT (close (255) == 0);
       ASSERT (close (256) == 0);
     }
-  ASSERT (dup2 (fd, bad_fd - 1) == bad_fd - 1);
-  ASSERT (close (bad_fd - 1) == 0);
   errno = 0;
   ASSERT (dup2 (fd, bad_fd) == -1);
   ASSERT (errno == EBADF);
diff --git a/tests/test-getdtablesize.c b/tests/test-getdtablesize.c
index a0325af..a83f8ec 100644
--- a/tests/test-getdtablesize.c
+++ b/tests/test-getdtablesize.c
@@ -29,8 +29,6 @@ int
 main (int argc, char *argv[])
 {
   ASSERT (getdtablesize () >= 3);
-  ASSERT (dup2 (0, getdtablesize() - 1) == getdtablesize () - 1);
-  ASSERT (dup2 (0, getdtablesize()) == -1);
 
   return 0;
 }