Height/Width/Duration Validator POC

iiif_prezi3/skeleton.py

@@ -7,7 +7,8 @@
 from datetime import datetime
 from typing import Any, Dict, List, Optional, Union
 
-from pydantic import AnyUrl, Extra, Field, PositiveFloat, PositiveInt, constr
+from pydantic import (AnyUrl, Extra, Field, PositiveFloat, PositiveInt, constr,
+                      root_validator)
 
 from .base import Base
 
@@ -288,9 +289,9 @@ class Annotation(Class):
 
 class Canvas(Class):
     type: constr(regex=r'^Canvas$') = 'Canvas'
-    height: Optional[Dimension] = None
-    width: Optional[Dimension] = None
-    duration: Optional[Duration] = None
+    height: Optional[Dimension]
+    width: Optional[Dimension]
+    duration: Optional[Duration]
     metadata: Optional[Metadata] = None
     summary: Optional[LngString] = None
     requiredStatement: Optional[KeyValueString] = None
@@ -310,6 +311,21 @@ class Canvas(Class):
     items: List[AnnotationPage]
     annotations: Optional[List[AnnotationPage]] = None
 
+    @root_validator
+    def hw_andor_d(cls, values):
+        """Validates that height/width and/or duration are set"""
+        assert (values['height'] is not None or values['width'] is not None or values['duration'] is not None), 'height/width and/or duration must be present'
+        return values
+
+    @root_validator
+    def both_hw(cls, values):
+        """Validates that height and width are both set if one is"""
+        if values['height'] is not None:
+            assert values['width'] is not None, 'width must be present if height is present'
+        if values['width'] is not None:
+            assert values['height'] is not None, 'height must be present if width is present'
+        return values
+
 
 class PlaceholderCanvas(Class):
     type: constr(regex=r'^Canvas$') = 'Canvas'

tests/test_validators.py

@@ -0,0 +1,25 @@
+import unittest
+
+from pydantic import ValidationError
+
+from iiif_prezi3 import Canvas
+
+
+class CanvasValidatorsTests(unittest.TestCase):
+    def test_hw_andor_d(self):
+        """Test the height&width and/or duration validator."""
+        with self.assertRaises(ValidationError):
+            Canvas()
+        c = Canvas(height=100, width=100)
+        self.assertEqual(c.height, 100)
+        c = Canvas(duration=100.0)
+        self.assertEqual(c.duration, 100.0)
+
+    def test_h_and_w(self):
+        """Test that including height or width requires the other."""
+        with self.assertRaises(ValidationError):
+            Canvas(height=100)
+        with self.assertRaises(ValidationError):
+            Canvas(width=100)
+        with self.assertRaises(ValidationError):
+            Canvas(height=100, duration=100.0)