Add test case for root with max_pathlen=0
This was already working but not tested so far
(Test case from previous commit still failing.)
Test certificates generated with:
programs/pkey/gen_key type=ec ec_curve=secp256r1 filename=cert91.key
programs/pkey/gen_key type=ec ec_curve=secp256r1 filename=cert92.key
programs/x509/cert_write serial=91 output_file=cert91.crt is_ca=1 \
issuer_key=cert91.key issuer_name="CN=Root 9,O=mbed TLS,C=UK" \
selfsign=1 max_pathlen=0
programs/x509/cert_write serial=92 output_file=cert92.crt \
issuer_key=cert91.key issuer_name="CN=Root 9,O=mbed TLS,C=UK" \
subject_key=cert92.key subject_name="CN=EE 92,O=mbed TLS,C=UK"
mv cert9?.crt tests/data_files/dir4
rm cert9?.key
diff --git a/tests/data_files/dir4/Readme b/tests/data_files/dir4/Readme
index 7217b75..3f1f610 100644
--- a/tests/data_files/dir4/Readme
+++ b/tests/data_files/dir4/Readme
@@ -40,3 +40,8 @@
```
cert81.crt -> cert82.crt (max_pathlen=0) -> cert83.crt
```
+
+9. zero pathlen constraint on trusted root (valid)
+```
+cert91.crt (max_pathlen=0) -> cert92.crt
+```