Implement Extension.to_json_serializable

scadnano/scadnano.py

@@ -2063,7 +2063,12 @@ class Extension(_JSONSerializable, Generic[DomainLabel]):
     _parent_strand: Optional['Strand'] = field(init=False, repr=False, compare=False, default=None)
 
     def to_json_serializable(self, suppress_indent: bool = True, **kwargs: Any) -> Union[Dict[str, Any], NoIndent]:
-        raise NotImplementedError()
+        json_map: Dict[str, Any] = {extension_key: self.num_bases}
+        self._add_display_length_if_not_default(json_map)
+        self._add_display_angle_if_not_default(json_map)
+        self._add_name_if_not_default(json_map)
+        self._add_label_if_not_default(json_map)
+        return json_map
 
     def dna_length(self) -> int:
         """Length of this :any:`Extension`; same as field :py:data:`Extension.length`."""
@@ -2094,6 +2099,27 @@ def float_transformer(x): return float(x)
             display_angle=display_angle,
             label=label, name=name)
 
+    def _add_display_length_if_not_default(self, json_map) -> None:
+        self._add_key_value_to_json_map_if_not_default(
+            key=display_length_key, value_callback=lambda x: x.display_length, json_map=json_map)
+
+    def _add_display_angle_if_not_default(self, json_map) -> None:
+        self._add_key_value_to_json_map_if_not_default(
+            key=display_angle_key, value_callback=lambda x: x.display_angle, json_map=json_map)
+
+    def _add_name_if_not_default(self, json_map) -> None:
+        self._add_key_value_to_json_map_if_not_default(
+            key=domain_name_key, value_callback=lambda x: x.name, json_map=json_map)
+
+    def _add_label_if_not_default(self, json_map) -> None:
+        self._add_key_value_to_json_map_if_not_default(
+            key=domain_label_key, value_callback=lambda x: x.label, json_map=json_map)
+
+    def _add_key_value_to_json_map_if_not_default(
+            self, key: str, value_callback: Callable[["Extension"], Any], json_map: Dict[str, Any]) -> None:
+        if value_callback(self) != value_callback(_default_extension):
+            json_map[key] = value_callback(self)
+
 
 # Default Extension object to allow for access to default extension values. num_bases is a dummy.
 _default_extension: Extension = Extension(num_bases=5)

tests/scadnano_tests.py

@@ -4881,20 +4881,6 @@ def test_to_json_extension_design__extension(self) -> None:
         self.assertIn("extension", document["strands"][0]["domains"][1])
         self.assertEqual(5, document["strands"][0]["domains"][1]["extension"])
 
-    def test_to_json_extension_design__relative_offset(self) -> None:
-        # Setup
-        design = sc.Design(helices=[sc.Helix(max_offset=100)], strands=[], grid=sc.square)
-        design.draw_strand(0, 0).to(10).extension_3p(5).with_relative_offset((1.4, -0.3))
-
-        # Action
-        result = design.to_json()
-
-        # Verify
-        document = json.loads(result)
-        self.assertEqual(2, len(document["strands"][0]["domains"]))
-        self.assertIn("relative_offset", document["strands"][0]["domains"][1])
-        self.assertEqual([1.4, -0.3], document["strands"][0]["domains"][1]["relative_offset"])
-
 
 class TestIllegalStructuresPrevented(unittest.TestCase):
 
@@ -7370,4 +7356,51 @@ def test_plate_map_markdown(self) -> None:
 | G   |          |          |          |     |     |     |          |     |     |      |      |      |
 | H   |          |          |          |     |     |     |          |     |     |      |      |      |
 """.strip()
-        self.assertEqual(expected_md, actual_md)
+        self.assertEqual(expected_md, actual_md)
+
+
+class TestExtension(unittest.TestCase):
+    def test_to_json_serializable__extension_key_contains_num_bases(self) -> None:
+        ext = sc.Extension(5)
+        result = ext.to_json_serializable()
+        self.assertEqual(result["extension"], 5)
+
+    def test_to_json_serializable__no_display_length_key_when_default_display_length(self) -> None:
+        ext = sc.Extension(5)
+        result = ext.to_json_serializable()
+        self.assertNotIn("display_length", result)
+
+    def test_to_json_serializable__no_display_angle_key_when_default_display_angle(self) -> None:
+        ext = sc.Extension(5)
+        result = ext.to_json_serializable()
+        self.assertNotIn("display_angle", result)
+
+    def test_to_json_serializable__no_name_key_when_default_name(self) -> None:
+        ext = sc.Extension(5)
+        result = ext.to_json_serializable()
+        self.assertNotIn("name", result)
+
+    def test_to_json_serializable__no_label_key_when_default_label(self) -> None:
+        ext = sc.Extension(5)
+        result = ext.to_json_serializable()
+        self.assertNotIn("label", result)
+
+    def test_to_json_serializable__display_length_key_contains_non_default_display_length(self) -> None:
+        ext = sc.Extension(5, display_length=1.9)
+        result = ext.to_json_serializable()
+        self.assertEqual(result["display_length"], 1.9)
+
+    def test_to_json_serializable__display_angle_key_contains_non_default_display_angle(self) -> None:
+        ext = sc.Extension(5, display_angle=39.9)
+        result = ext.to_json_serializable()
+        self.assertEqual(result["display_angle"], 39.9)
+
+    def test_to_json_serializable__name_key_contains_non_default_name(self) -> None:
+        ext = sc.Extension(5, name="A")
+        result = ext.to_json_serializable()
+        self.assertEqual(result["name"], "A")
+
+    def test_to_json_serializable__label_key_contains_non_default_name(self) -> None:
+        ext = sc.Extension(5, label="ext1")
+        result = ext.to_json_serializable()
+        self.assertEqual(result["label"], "ext1")