Add tests for x509parse_key_ec()

Test files were generated as follows:

openssl ecparam -name prime192v1 -genkey > key.pem

openssl ec -in key.pem -pubout -outform PEM > pub.pem
openssl ec -in key.pem -pubout -outform DER > pub.der

openssl ec -in key.pem -outform pem > prv.sec1.pem
openssl ec -in key.pem -outform der > prv.sec1.der
openssl ec -in key.pem -des -passout pass:polar -outform pem > prv.sec1.pw.pem

openssl pkcs8 -topk8 -in key.pem -nocrypt -outform pem > prv.pk8.pem
openssl pkcs8 -topk8 -in key.pem -nocrypt -outform der > prv.pk8.der
openssl pkcs8 -topk8 -in key.pem -passout pass:polar -outform der \
    > prv.pk8.pw.der
openssl pkcs8 -topk8 -in key.pem -passout pass:polar -outform pem \
    > prv.pk8.pw.pem
diff --git a/tests/suites/test_suite_x509parse.function b/tests/suites/test_suite_x509parse.function
index ebb534a..57653f7 100644
--- a/tests/suites/test_suite_x509parse.function
+++ b/tests/suites/test_suite_x509parse.function
@@ -201,6 +201,27 @@
 END_CASE
 
 BEGIN_CASE
+x509parse_keyfile_ec:key_file:password:result
+{
+    ecp_keypair eckey;
+    int res;
+
+    ecp_keypair_init( &eckey );
+
+    res = x509parse_keyfile_ec( &eckey, {key_file}, {password} );
+
+    TEST_ASSERT( res == {result} );
+
+    if( res == 0 )
+    {
+        TEST_ASSERT( ecp_check_prvkey( &eckey.grp, &eckey.d ) == 0 );
+    }
+
+    ecp_keypair_free( &eckey );
+}
+END_CASE
+
+BEGIN_CASE
 x509parse_crt:crt_data:result_str:result
 {
     x509_cert   crt;