Fix float validation using decimal.Decimal (#1073)

* Fix float validation using decimal.Decimal

* Force string repr of the float when loading yaml

---------

Co-authored-by: Jonathan Senecal <jonathan.senecal@metrooptic.com>

schema/components.json

@@ -605,7 +605,7 @@
                 "value": {
                     "type": "number",
                     "minimum": 0,
-                    "multipleOfPrecision": 0.01
+                    "multipleOf": 0.01
                 },
                 "unit": {
                     "type": "string",

tests/definitions_test.py

@@ -1,11 +1,14 @@
+import decimal
 import glob
 import json
 import os
+from urllib.request import urlopen
+
 import pytest
 import yaml
-from jsonschema import RefResolver, Draft4Validator
+from jsonschema import Draft4Validator, RefResolver
 from jsonschema.exceptions import ValidationError
-
+from yaml_loader import DecimalSafeLoader
 
 SCHEMAS = (
     ('device-types', 'devicetype.json'),
@@ -35,7 +38,7 @@ def _get_definition_files():
 
         # Initialize the schema
         with open(f"schema/{schema}") as schema_file:
-            schema = json.loads(schema_file.read())
+            schema = json.loads(schema_file.read(), parse_float=decimal.Decimal)
 
         # Validate that the schema exists
         assert schema, f"Schema definition for {path} is empty!"
@@ -51,6 +54,12 @@ definition_files = _get_definition_files()
 known_slugs = set()
 
 
+def _decimal_file_handler(uri):
+    with urlopen(uri) as url:
+        result = json.loads(url.read().decode("utf-8"), parse_float=decimal.Decimal)
+    return result
+
+
 def test_environment():
     """
     Run basic sanity checks on the environment to ensure tests are running correctly.
@@ -75,11 +84,15 @@ def test_definitions(file_path, schema):
     assert content.endswith('\n'), "Missing trailing newline"
 
     # Load YAML data from file
-    definition = yaml.load(content, Loader=yaml.SafeLoader)
+    definition = yaml.load(content, Loader=DecimalSafeLoader)
 
     # Validate YAML definition against the supplied schema
     try:
-        resolver = RefResolver(f'file://{os.getcwd()}/schema/devicetype.json', schema)
+        resolver = RefResolver(
+            f"file://{os.getcwd()}/schema/devicetype.json",
+            schema,
+            handlers={"file": _decimal_file_handler},
+        )
         Draft4Validator(schema, resolver=resolver).validate(definition)
     except ValidationError as e:
         pytest.fail(f"{file_path} failed validation: {e}", False)

tests/yaml_loader.py

@@ -0,0 +1,34 @@
+import decimal
+
+from yaml.composer import Composer
+from yaml.constructor import SafeConstructor
+from yaml.parser import Parser
+from yaml.reader import Reader
+from yaml.resolver import Resolver
+from yaml.scanner import Scanner
+
+
+class DecimalSafeConstructor(SafeConstructor):
+    """Special constructor to override construct_yaml_float() in order to cast "Decimal" types to the value"""
+
+    def construct_yaml_float(self, node):
+        value = super().construct_yaml_float(node)
+        # We force the string representation of the float here to avoid things like:
+        # In [11]: decimal.Decimal(10.11)
+        # Out[11]: Decimal('10.1099999999999994315658113919198513031005859375')
+        return decimal.Decimal(f"{value}")
+
+
+DecimalSafeConstructor.add_constructor(
+    "tag:yaml.org,2002:float", DecimalSafeConstructor.construct_yaml_float
+)
+
+
+class DecimalSafeLoader(Reader, Scanner, Parser, Composer, DecimalSafeConstructor, Resolver):
+    def __init__(self, stream):
+        Reader.__init__(self, stream)
+        Scanner.__init__(self)
+        Parser.__init__(self)
+        Composer.__init__(self)
+        DecimalSafeConstructor.__init__(self)
+        Resolver.__init__(self)