feat: add basic fuzz testing

.gitignore

@@ -31,7 +31,10 @@ src/hiero_sdk_python/hapi
 # Pytest
 .pytest_cache
 
+# Hypothesis state
+.hypothesis/
+
 # Lock files
 uv.lock
 pdm.lock
-pubkey.asc
+pubkey.asc

CHANGELOG.md

@@ -40,11 +40,10 @@ This changelog is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.
 - docs(setup): specify unit tests for local setup verification. (#1856)
 - doc: Fix testnet link in README.md. (#1879)
 
-
-
 ### Tests
 - Format `tests/unit/endpoint_test.py` using black. (`#1792`)
 - Implement TCK JSON-RPC server with request handling and error management
+- Implement basic fuzz testing [#1872](https://github.com/hiero-ledger/hiero-sdk-python/issues/1872)
 
 ### .github
 - Added triage members max assignment is protected from being a mentor in `.github/scripts/bot-assignment-check.sh`. (#1718)

pyproject.toml

@@ -48,6 +48,7 @@ dev = [
     "grpcio-tools>=1.76.0,<2",
     "pytest>=8.3.4,<9",
     "pytest-cov>=7.0.0,<8",
+    "hypothesis>=6.0"
 ]
 
 lint = [

pytest.ini

@@ -4,4 +4,5 @@ pythonpath = src
 
 markers =
     integration: mark a test as an integration test.
-    unit: mark a test as a unit test. 
+    unit: mark a test as a unit test. 
+    fuzz: mark a test as fuzz test.

src/hiero_sdk_python/hbar.py

@@ -45,6 +45,8 @@ def __init__(
 
         if isinstance(amount, float) and not math.isfinite(amount):
             raise ValueError("Hbar amount must be finite")
+        if isinstance(amount, Decimal) and not amount.is_finite():
+            raise ValueError("Hbar amount must be finite")
 
         if  unit == HbarUnit.TINYBAR:
             if not isinstance(amount, int):
@@ -56,7 +58,7 @@ def __init__(
             amount = Decimal(str(amount))
 
         tinybar = amount * Decimal(unit.tinybar)
-        if tinybar % 1 != 0:
+        if tinybar != tinybar.to_integral_value():
             raise ValueError("Fractional tinybar value not allowed")
 
         self._amount_in_tinybar = int(tinybar)
@@ -67,7 +69,7 @@ def to(self, unit: HbarUnit) -> float:
 
     def to_tinybars(self) -> int:
         """Return the amount of hbars in tinybars."""
-        return int(self.to(HbarUnit.TINYBAR))
+        return self._amount_in_tinybar
 
     def to_hbars(self) -> float:
         """
@@ -220,4 +222,4 @@ def __ge__(self, other: object) -> bool:
 
 Hbar.ZERO = Hbar(0)
 Hbar.MAX = Hbar(50_000_000_000)
-Hbar.MIN = Hbar(-50_000_000_000)
+Hbar.MIN = Hbar(-50_000_000_000)

tests/fuzz/__init__.py

@@ -0,0 +1 @@
+# with <3 from Anto