diff --git a/.gitignore b/.gitignore
index 9c882b7..bade9fc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,4 @@
 __pycache__/
 *.egg-info/
+.mypy_cache/
+/build/
diff --git a/pbcabi/model.py b/pbcabi/model.py
index 793083b..b25c023 100644
--- a/pbcabi/model.py
+++ b/pbcabi/model.py
@@ -14,6 +14,9 @@ from enum import Enum
 import enforce_typing
 from .binaryreader import BinaryReader
 import pbcabi.data as data
+import logging
+
+logger = logging.getLogger(__name__)
 
 Identifier = str
 
@@ -242,6 +245,16 @@ class AvlTreeTypeSpec(MapTypeSpec):
     '''
     DISCRIMINANT = 0x19
 
+    @staticmethod
+    def read_from(reader: BinaryReader):
+        '''
+        Deserialize this 'TypeSpec' type from 'BinaryReader'.
+        '''
+        type_key = TypeSpec.read_from(reader)
+        type_value = TypeSpec.read_from(reader)
+        type_spec = AvlTreeTypeSpec(type_key, type_value)
+        return type_spec
+
 @enforce_typing.enforce_types
 @dataclasses.dataclass(frozen=True, slots=True)
 class InlineMapTypeSpec(MapTypeSpec):
@@ -528,6 +541,8 @@ class StructTypeSpec(NamedTypeSpec):
         '''
         Deserialize this 'TypeSpec' type from 'BinaryReader'.
         '''
+
+        logger.debug('Reading Struct')
         name = reader.readString()
         variants = reader.readList(FieldAbi.read_from)
         type_spec = StructTypeSpec(name, type_index, variants)
diff --git a/test/example-abis/025FA781D389D7C7CAAF836E5E47ABED6CEFD2D928.abi b/test/example-abis/025FA781D389D7C7CAAF836E5E47ABED6CEFD2D928.abi
new file mode 100644
index 0000000..5209198
Binary files /dev/null and b/test/example-abis/025FA781D389D7C7CAAF836E5E47ABED6CEFD2D928.abi differ
diff --git a/test/test_address.py b/test/test_address.py
new file mode 100644
index 0000000..17c3898
--- /dev/null
+++ b/test/test_address.py
@@ -0,0 +1,19 @@
+import pytest
+from pathlib import Path
+from pbcabi.binaryreader import BinaryReader
+import pbcabi.model
+from pbcabi.data import BlockchainAddress
+
+EXAMPLE_SHARDS = [
+        ("Shard1", 2, "000000000000000000000000000000000000000001"),
+        ("Shard0", 2, "000000000000000000000000000000000000000002"),
+        ("Shard0", 3, "025FA781D389D7C7CAAF836E5E47ABED6CEFD2D928"),
+        ("Shard1", 3, "04FE17D1009372C8ED3AC5B790B32E349359C2C7E9"),
+        ("Shard0", 3, "01A2020BB33EF9E0323C7A3210D5CB7FD492AA0D65"),
+]
+
+@pytest.mark.parametrize('shard_id,num_shards,address', EXAMPLE_SHARDS)
+def test_parse_abi(shard_id: int, num_shards:int, address: str):
+    address = BlockchainAddress.from_hex_hash(address)
+    assert address.shard_id(num_shards) == shard_id
+
diff --git a/test/test_binaryreader.py b/test/test_binaryreader.py
new file mode 100644
index 0000000..27e8c93
--- /dev/null
+++ b/test/test_binaryreader.py
@@ -0,0 +1,18 @@
+import pytest
+from pathlib import Path
+from pbcabi.binaryreader import BinaryReader
+import pbcabi.model
+
+def assert_parse(hex, value):
+    derp = bytes.fromhex(hex)
+    assert BinaryReader(derp).readSignedIntBigEndian(1) == value
+
+def test_parse():
+    assert_parse('00', 0)
+    assert_parse('01', 1)
+    assert_parse('10', 0x10)
+    assert_parse('79', 0x79)
+    assert_parse('80', -0x80)
+    assert_parse('F0', -16)
+    assert_parse('FF', -1)
+