This also replaces instances where we manually write "return ctx.Err()"
with "return context.Cause(ctx)" which is functionally identical, but
will also correctly propagate cause errors if present.
Prior to this commit, temporary directories in tests were created using
`filepath.Join` and `os.MkdirAll`.
This commit replaces `os.MkdirAll` with `t.TempDir` in tests. The
directory created by `t.TempDir` is automatically removed when the test
and all its subtests complete.
Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
