Fix some bugs with multithreaded tests:

* kmod tests must run exclusively, because they load and unload a module
  with a constant name.
* A few tests were doing some variant of chdir, but weren't taking the
  CWD_MTX.
* The kmod tests read files by path relative to CWD, so they need the
  CWD_MTX.  But they don't need it exclusively, so convert the CWD_MTX
  into an RwLock.
* Tests that do change the cwd need to change it back when they're done.

1 files changed, 2 insertions, 0 deletions

diff --git a/test/test_stat.rs b/test/test_stat.rs
index fae8df82..b9da7fc3 100644
--- a/test/test_stat.rs
+++ b/test/test_stat.rs
@@ -154,6 +154,7 @@ fn test_fchmod() {
 
 #[test]
 fn test_fchmodat() {
+    let _dr = ::DirRestore::new();
     let tempdir = tempfile::tempdir().unwrap();
     let filename = "foo.txt";
     let fullpath = tempdir.path().join(filename);
@@ -241,6 +242,7 @@ fn test_futimens() {
 
 #[test]
 fn test_utimensat() {
+    let _dr = ::DirRestore::new();
     let tempdir = tempfile::tempdir().unwrap();
     let filename = "foo.txt";
     let fullpath = tempdir.path().join(filename);