std: add changing cur dir back

There's a good argument to not have this in the std lib but it's more
work to remove it than to leave it in, and this branch is already
20,000+ lines changed.

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/std/testing.zig b/lib/std/testing.zig
index 5b5ec852e9..9519eeb427 100644
--- a/lib/std/testing.zig
+++ b/lib/std/testing.zig
@@ -629,6 +629,7 @@ pub const TmpDir = struct {
 };
 
 pub fn tmpDir(opts: Io.Dir.OpenOptions) TmpDir {
+    comptime assert(builtin.is_test);
     var random_bytes: [TmpDir.random_bytes_count]u8 = undefined;
     std.crypto.random.bytes(&random_bytes);
     var sub_path: [TmpDir.sub_path_len]u8 = undefined;