Add: evs decoding - no working tests yet

EVS decoding should be mostly working now. We do not have any
tests yet, because it is unclear to me how EVS is defined in
dictionaries.

tests/test_parse_header.py

@@ -148,10 +148,34 @@ def flattened_product(l1, l2):
     return result
 
 
+def transform_attr_to_extended_evs(attributes):
+    vendor_id = (1234).to_bytes(4, "big")
+    new_attrs = []
+    for attr, result in attributes:
+        length = (attr[1] + 6).to_bytes(1, "big")
+        orig_type = attr[0].to_bytes(1, "big")
+        attr = b"\x13" + length + b"\x15" + vendor_id + orig_type + attr[2:]
+        new_attrs.append((attr, result))
+    return new_attrs
+
+
+def transform_attr_to_longextended_evs(attributes):
+    vendor_id = (1234).to_bytes(4, "big")
+    new_attrs = []
+    for attr, result in attributes:
+        length = (attr[1] + 7).to_bytes(1, "big")
+        orig_type = attr[0].to_bytes(1, "big")
+        attr = b"\x14" + length + b"\x15" + b"\x00" + vendor_id + orig_type + attr[2:]
+        new_attrs.append((attr, result))
+    return new_attrs
+
+
 VENDOR_TEST_ATTRIBUTES = flattened_product(VENDOR_FORMAT_COMBINATIONS, TEST_ATTRIBUTES)
 VENDOR_TAGGED_ATTRIBUTES = flattened_product(
     VENDOR_FORMAT_COMBINATIONS, TAGGED_ATTRIBUTES
 )
+VENDOR_EXTENDED_EVS_ATTRIBUTES = transform_attr_to_extended_evs(TEST_ATTRIBUTES)
+VENDOR_LONGEXTENDED_EVS_ATTRIBUTES = transform_attr_to_longextended_evs(TEST_ATTRIBUTES)
 
 
 @pytest.fixture
@@ -191,6 +215,24 @@ def test_decode_attribute_rfc_tagged(radius_dictionary, attr_bytes, expected):
     assert attrs[0].tag == 1
 
 
+@pytest.mark.parametrize("attr_bytes, expected", VENDOR_EXTENDED_EVS_ATTRIBUTES)
+def test_decode_extended_evs(radius_dictionary, attr_bytes, expected):
+    raw_packet = bytes(20) + attr_bytes
+    attrs = utils.decode_attributes(radius_dictionary, raw_packet)
+    assert len(attrs) == 1
+    assert attrs[0].value == expected
+    assert attrs[0].tag == 0
+
+
+@pytest.mark.parametrize("attr_bytes, expected", VENDOR_LONGEXTENDED_EVS_ATTRIBUTES)
+def test_decode_longextended_evs(radius_dictionary, attr_bytes, expected):
+    raw_packet = bytes(20) + attr_bytes
+    attrs = utils.decode_attributes(radius_dictionary, raw_packet)
+    assert len(attrs) == 1
+    assert attrs[0].value == expected
+    assert attrs[0].tag == 0
+
+
 def generate_vendor_attribute(vendor_id, tlen, llen, attr_bytes):
     vendor_id = vendor_id.to_bytes(4, "big")
     vsa_length = (4 + tlen + llen + len(attr_bytes)).to_bytes(1, "big")