Nicer interface between PK and debug.

Finally get rid of pk_context.type member, too.
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index cec4d8d..6bda6fa 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -226,7 +226,7 @@
     if( res == 0 )
     {
         ecp_keypair *eckey;
-        TEST_ASSERT( ctx.type == POLARSSL_PK_ECKEY );
+        TEST_ASSERT( pk_can_do( &ctx, POLARSSL_PK_ECKEY ) );
         eckey = (ecp_keypair *) ctx.data;
         TEST_ASSERT( ecp_check_pubkey( &eckey->grp, &eckey->Q ) == 0 );
     }
@@ -250,7 +250,7 @@
     if( res == 0 )
     {
         ecp_keypair *eckey;
-        TEST_ASSERT( ctx.type == POLARSSL_PK_ECKEY );
+        TEST_ASSERT( pk_can_do( &ctx, POLARSSL_PK_ECKEY ) );
         eckey = (ecp_keypair *) ctx.data;
         TEST_ASSERT( ecp_check_privkey( &eckey->grp, &eckey->d ) == 0 );
     }