"""Unit tests for digest computation helper.""" import hashlib import jcs import pytest from mcp_hangar.domain.services.digest_computation import compute_tool_digest from mcp_hangar.domain.value_objects.tool_digest import ToolDigest class TestComputeToolDigest: """compute_tool_digest canonical hashing behavior.""" @pytest.fixture def sample_tool(self): return { "name": "read_file", "description": "Read a file from disk", "inputSchema": { "type": "object", "properties": {"path": {"type": "string"}}, }, } def test_returns_tool_digest(self, sample_tool): result = compute_tool_digest(sample_tool) assert isinstance(result, ToolDigest) assert result.tool_name == "read_file" assert result.algorithm == "sha256" assert len(result.sha256) == 64 def test_deterministic(self, sample_tool): d1 = compute_tool_digest(sample_tool) d2 = compute_tool_digest(sample_tool) assert d1.sha256 == d2.sha256 def test_key_order_independent(self, sample_tool): reordered = { "inputSchema": sample_tool["inputSchema"], "description": sample_tool["description"], "name": sample_tool["name"], } assert compute_tool_digest(sample_tool).sha256 == compute_tool_digest(reordered).sha256 def test_nested_key_order_independent(self): tool_a = { "name": "t", "inputSchema": {"properties": {"a": {"type": "string"}, "b": {"type": "int"}}, "type": "object"}, } tool_b = { "name": "t", "inputSchema": {"type": "object", "properties": {"b": {"type": "int"}, "a": {"type": "string"}}}, } assert compute_tool_digest(tool_a).sha256 == compute_tool_digest(tool_b).sha256 def test_different_description_different_digest(self, sample_tool): modified = {**sample_tool, "description": "DIFFERENT"} assert compute_tool_digest(sample_tool).sha256 != compute_tool_digest(modified).sha256 def test_different_schema_different_digest(self, sample_tool): modified = {**sample_tool, "inputSchema": {"type": "string"}} assert compute_tool_digest(sample_tool).sha256 != compute_tool_digest(modified).sha256 def test_different_name_different_digest(self, sample_tool): modified = {**sample_tool, "name": "write_file"} assert compute_tool_digest(sample_tool).sha256 != compute_tool_digest(modified).sha256 def test_output_schema_included_when_present(self, sample_tool): with_output = {**sample_tool, "outputSchema": {"type": "string"}} without_output = sample_tool assert compute_tool_digest(with_output).sha256 != compute_tool_digest(without_output).sha256 def test_output_schema_none_omitted(self, sample_tool): with_none = {**sample_tool, "outputSchema": None} without = sample_tool assert compute_tool_digest(with_none).sha256 == compute_tool_digest(without).sha256 def test_empty_output_schema_equals_absent(self): tool_absent = {"name": "x"} tool_empty = {"name": "x", "outputSchema": {}} assert compute_tool_digest(tool_absent).sha256 == compute_tool_digest(tool_empty).sha256 def test_empty_description_equals_absent(self): tool_absent = {"name": "x"} tool_empty = {"name": "x", "description": ""} assert compute_tool_digest(tool_absent).sha256 == compute_tool_digest(tool_empty).sha256 def test_empty_input_schema_equals_absent(self): tool_absent = {"name": "x"} tool_empty = {"name": "x", "inputSchema": {}} assert compute_tool_digest(tool_absent).sha256 == compute_tool_digest(tool_empty).sha256 def test_empty_list_input_schema_equals_absent(self): tool_absent = {"name": "x"} tool_empty = {"name": "x", "inputSchema": []} assert compute_tool_digest(tool_absent).sha256 == compute_tool_digest(tool_empty).sha256 def test_populated_values_are_meaningful(self): base = {"name": "x"} with_desc = {"name": "x", "description": "d"} with_schema = {"name": "x", "inputSchema": {"type": "object"}} assert compute_tool_digest(base).sha256 != compute_tool_digest(with_desc).sha256 assert compute_tool_digest(base).sha256 != compute_tool_digest(with_schema).sha256 def test_extra_fields_ignored(self, sample_tool): with_extra = {**sample_tool, "annotations": {"readOnly": True}, "extra_field": "ignored"} assert compute_tool_digest(sample_tool).sha256 == compute_tool_digest(with_extra).sha256 def test_missing_description_omitted(self): tool = {"name": "minimal", "inputSchema": {"type": "object"}} tool_with_none = {"name": "minimal", "description": None, "inputSchema": {"type": "object"}} result = compute_tool_digest(tool) assert result.tool_name == "minimal" assert len(result.sha256) == 64 assert compute_tool_digest(tool).sha256 == compute_tool_digest(tool_with_none).sha256 def test_empty_name_raises(self): with pytest.raises(ValueError, match="'name'"): compute_tool_digest({"name": "", "inputSchema": {}}) def test_missing_name_raises(self): with pytest.raises(ValueError, match="'name'"): compute_tool_digest({"description": "no name"}) def test_none_name_raises(self): with pytest.raises(ValueError, match="'name'"): compute_tool_digest({"name": None}) def test_numeric_name_raises(self): with pytest.raises(ValueError, match="'name'"): compute_tool_digest({"name": 123}) def test_canonical_form_matches_jcs_reference(self): tool = {"name": "t", "description": "d", "inputSchema": {"type": "object"}} expected_payload = {"description": "d", "inputSchema": {"type": "object"}, "name": "t"} expected_bytes = jcs.canonicalize(expected_payload) expected_hash = hashlib.sha256(expected_bytes).hexdigest() assert compute_tool_digest(tool).sha256 == expected_hash def test_unicode_in_description(self): tool = {"name": "t", "description": "Przetwarzanie danych"} result = compute_tool_digest(tool) assert len(result.sha256) == 64 def test_non_ascii_emoji_produces_utf8_digest(self): """RFC 8785 requires literal UTF-8, not \\uXXXX escapes.""" tool = {"name": "t", "description": "cafe \u0301\U0001f680"} expected_payload = {"description": "cafe \u0301\U0001f680", "name": "t"} expected_bytes = jcs.canonicalize(expected_payload) expected_hash = hashlib.sha256(expected_bytes).hexdigest() result = compute_tool_digest(tool) assert result.sha256 == expected_hash def test_non_ascii_differs_from_escaped(self): """Verify JCS literal UTF-8 differs from json.dumps ensure_ascii=True.""" import json tool = {"name": "t", "description": "cafe \u0301\U0001f680"} canonical_payload = {"description": "cafe \u0301\U0001f680", "name": "t"} ascii_serialized = json.dumps(canonical_payload, sort_keys=True, separators=(",", ":")) ascii_hash = hashlib.sha256(ascii_serialized.encode("utf-8")).hexdigest() jcs_hash = compute_tool_digest(tool).sha256 assert jcs_hash != ascii_hash def test_empty_input_schema(self): tool = {"name": "t", "inputSchema": {}} result = compute_tool_digest(tool) assert len(result.sha256) == 64 def test_empty_tool_dict_raises(self): with pytest.raises(ValueError, match="'name'"): compute_tool_digest({})