add decode test cases

Author: semuadmin

Diff for: .gitignore

@@ -19,7 +19,8 @@ src/pyspartn.egg-*
 /pyspartn/__pycache__
 /tests/__pycache__
 *.pyc
-/examples/temp*.py
+/examples/temp*.*
+/examples/test*.*
 /.pytest_cache/
 pylint_report.txt
 venv

Diff for: .vscode/tasks.json

@@ -118,7 +118,7 @@
                 "--cov-report",
                 "html",
                 "--cov-fail-under",
-                "60",
+                "80",
                 "--cov=${config:distname}",
                 "tests/",
             ],

Diff for: pyproject.toml

@@ -78,7 +78,7 @@ disable = """
 
 [tool.pytest.ini_options]
 minversion = "7.0"
-addopts = "--cov --cov-report term-missing --cov-fail-under 60"
+addopts = "--cov --cov-report term-missing --cov-fail-under 80"
 pythonpath = ["src"]
 
 [tool.coverage.run]

Diff for: src/pyspartn/spartnhelpers.py

@@ -13,6 +13,7 @@
 from datetime import datetime
 from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
 from pyspartn.spartntypes_core import TIMEBASE
+from pyspartn.exceptions import SPARTNMessageError
 
 
 def att2idx(att: str) -> int:
@@ -49,18 +50,21 @@ def att2name(att: str) -> str:
 
 def bitsval(bitfield: bytes, position: int, length: int) -> int:
     """
-    Get unisgned integer value of masked bits in bitfield.
+    Get unisgned integer value of masked bits in bytes.
 
     :param bytes bitfield: bytes
     :param int position: position in bitfield, from leftmost bit
     :param int length: length of masked bits
     :return: value
     :rtype: int
+    :raises: SPARTNMessageError if end of bitfield
     """
 
     lbb = len(bitfield) * 8
     if position + length > lbb:
-        return None
+        raise SPARTNMessageError(
+            f"Attribute size {length} exceeds remaining payload length {lbb - position}"
+        )
 
     return (
         int.from_bytes(bitfield, "big") >> (lbb - position - length) & 2**length - 1

Diff for: src/pyspartn/spartnmessage.py

@@ -154,9 +154,9 @@ def _do_attributes(self):
         # decrypt payload if encrypted
         if self.eaf and self._decode:
             iv = self._get_iv()
-            self.payload = decrypt(payload, self._key, iv)
+            self._payload = decrypt(payload, self._key, iv)
         else:
-            self.payload = payload
+            self._payload = payload
 
         key = ""
         try:
@@ -219,7 +219,6 @@ def _get_attr_sfx(self, key: str, index: list) -> str:
         for i in range(keyl + 1):
             n = index[i]
             keyr += f"_{n:02d}"
-        # print(f"DEBUG _set_attribute_group nested depth {key} {keyl} {keyr}")
         return keyr
 
     def _set_attribute(self, offset: int, pdict: dict, key: str, index: list) -> tuple:
@@ -234,7 +233,6 @@ def _set_attribute(self, offset: int, pdict: dict, key: str, index: list) -> tup
         :rtype: tuple
         """
 
-        # print(f"DEBUG set_attribute {self} index {index} key {key}")
         att = pdict[key]  # get attribute type
         if isinstance(att, tuple):  # attribute group
             siz, _ = att
@@ -352,7 +350,7 @@ def _set_attribute_single(
             attlen = self._getvarlen(key, index)
         if not self._scaling:
             res = 0
-        val = bitsval(self.payload, offset, attlen)
+        val = bitsval(self._payload, offset, attlen)
 
         setattr(self, keyr, val)
 
@@ -384,7 +382,7 @@ def _getvarlen(self, key: str, index: list) -> int:
         :return: length of attribute in bits
         :rtype: int
         """
-        # pylint: disable=no-member
+        # pylint: disable=no-member, too-many-branches
 
         # if within repeating group, append nested index
         if len(index) > 0:
@@ -516,3 +514,14 @@ def identity(self) -> str:
         """
 
         return SPARTN_MSGIDS.get((self.msgType, self.msgSubtype), "UNKNOWN")
+
+    @property
+    def payload(self) -> bytes:
+        """
+        Return payload.
+
+        :return: payload
+        :rtype: bytes
+        """
+
+        return self._payload

Diff for: tests/spartnHPAC.log

@@ -0,0 +1,3 @@
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Diff for: tests/spartnOCB.log

@@ -24,6 +24,7 @@
     numbitsset,
 )
 from pyspartn.spartntypes_core import TIMEBASE
+from pyspartn.exceptions import SPARTNMessageError
 
 
 class StaticTest(unittest.TestCase):
@@ -35,14 +36,21 @@ def tearDown(self):
         pass
 
     def testbitsval(self):
-        bits = [(7, 1), (8, 8), (22, 2), (24, 4), (40, 16)]
-        EXPECTED_RESULT = [1, 8, 3, 15, None]
+        bits = [(7, 1), (8, 8), (22, 2), (24, 4)]
+        EXPECTED_RESULT = [1, 8, 3, 15]
 
         bm = b"\x01\x08\x03\xf0\xff"
         for i, (ps, ln) in enumerate(bits):
             res = bitsval(bm, ps, ln)
             self.assertEqual(res, EXPECTED_RESULT[i])
 
+    def testbitsvalerr(self):
+        EXPECTED_ERROR = "Attribute size 16 exceeds remaining payload length 2"
+        bm = b"\x01\x08\x03\xf0\xff"
+        # print(f"Length bitfield = {len(bm) * 8}")
+        with self.assertRaisesRegex(SPARTNMessageError, EXPECTED_ERROR):
+            res = bitsval(bm, 38, 16)
+
     def testnumbitsset(self):
         vals = [7, 8, 22, 24, 4167, 234876]
         EXPECTED_RESULT = [3, 1, 3, 2, 5, 11]