OTP import: support hash names with HMAC- prefix

Refactor convertHashName() method to accept hash names prefixed with
HMAC- or any other prefix. Extending the method should be easier in
future.

Add tests proposed by Rob Crittenden to make sure we don't regress
with expected behavior of convertHashName().

Fixes https://pagure.io/freeipa/issue/7146

Reviewed-By: Rob Crittenden <rcritten@redhat.com>

ipatests/test_ipaserver/test_otptoken_import.py

@@ -22,6 +22,7 @@ import os
 import pytest
 
 from ipaserver.install.ipa_otptoken_import import PSKCDocument, ValidationError
+from ipaserver.install.ipa_otptoken_import import convertHashName
 
 basename = os.path.join(os.path.dirname(__file__), "data")
 
@@ -129,3 +130,21 @@ class test_otptoken_import(object):
                 'ipatokenotpdigits': 8,
                 'type': u'hotp',
             })]
+
+    def test_valid_tokens(self):
+        assert convertHashName('sha1') == u'sha1'
+        assert convertHashName('hmac-sha1') == u'sha1'
+        assert convertHashName('sha224') == u'sha224'
+        assert convertHashName('hmac-sha224') == u'sha224'
+        assert convertHashName('sha256') == u'sha256'
+        assert convertHashName('hmac-sha256') == u'sha256'
+        assert convertHashName('sha384') == u'sha384'
+        assert convertHashName('hmac-sha384') == u'sha384'
+        assert convertHashName('sha512') == u'sha512'
+        assert convertHashName('hmac-sha512') == u'sha512'
+
+    def test_invalid_tokens(self):
+        """The conversion defaults to sha1 on unknown hashing"""
+        assert convertHashName('something-sha256') == u'sha1'
+        assert convertHashName('') == u'sha1'
+        assert convertHashName(None) == u'sha1'