Use nitrokey-test for nitrokey device tests

This change is the first in a series to migrate the existing tests to
using the nitrokey-test crate. The crate provides a couple of benefits
over the existing way testing works:
- test execution is automatically serialized (i.e., no more need for
  --test-threads)
- available devices are detected at runtime (i.e., no more need for
  --features test-pro)
- tests capable of running only on a specific device are automatically
  skipped if this device is not present

In addition to that, the crate also offers selection of particular
groups of tests by virtue of the NITROKEY_TEST_GROUP environment
variable. If set (valid values are "nodev", "pro", and "storage") only
tests of the particular group are run (those tests will fail if a
required precondition is not met, i.e., if a device is present but
"nodev" is set, or if the "pro" group is run but no device or a storage
device is present).

Unfortunately, it has some limitations as well. Most importantly Rust
does not allow us to indicate whether a test has been skipped or not.
While it has #[ignore] support, that strictly is a compile-time feature
and, hence, not usable.

This patch in particular pulls in the nitrokey-test crate and adjusts
the existing device tests to make use of it.

1 files changed, 3 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index b8f30db..3712dbe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,3 +20,6 @@ test-storage = []
 libc = "0.2"
 nitrokey-sys = "3.4"
 rand = "0.6"
+
+[dev-dependencies]
+nitrokey-test = {version = "0.1"}