test: add test for example node

.pre-commit-config.yaml

@@ -1,5 +1,6 @@
 # See https://pre-commit.com for more information
 # See https://pre-commit.com/hooks.html for more hooks
+default_install_hook_types: [pre-commit, pre-push, commit-msg]
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v4.6.0

tests/examples/test_node.py

@@ -0,0 +1,117 @@
+"""Tests example asdf-pydantic model for nodes of a graph/tree."""
+
+from __future__ import annotations
+
+import textwrap
+
+import asdf
+import asdf.exceptions
+import asdf.schema
+import pytest
+import yaml
+from asdf.extension import Extension
+
+from asdf_pydantic import AsdfPydanticConverter, AsdfPydanticModel
+
+
+class AsdfNode(AsdfPydanticModel):
+    """Model for a node in a graph/tree.
+
+    Nodes introduce self-referential types. Notice the type of the `child`
+    attribute it the node type itself. The ASDF schema for this model will require
+    self-referencing syntax. We assumes this form is valid for ASDF schemas:
+
+    ```yaml
+    ---
+    type: object
+    anyOf:
+      - $ref: "#/definitions/AsdfNode"
+    definitions:
+        AsdfNode:
+            type: object
+            properties:
+            name:
+                type: string
+            child:
+                anyOf:
+                - $ref: "#/definitions/AsdfNode"
+                - type: null
+    ```
+
+    The self-reference happens in ``definitions[AsdfNode].properties.child.anyOf[0]``
+    where the `$ref` is a special JSONSchema syntax that referes to the value,
+    `#/definitions/AsdfNode`. This value is a json path where `#` denotes "this
+    schema".
+    """
+
+    _tag = "asdf://asdf-pydantic/examples/tags/node-1.0.0"
+
+    name: str
+    child: AsdfNode | None = None
+
+
+@pytest.fixture()
+def asdf_extension():
+    """Registers an ASDF extension containing models for this test."""
+    AsdfPydanticConverter.add_models(AsdfNode)
+
+    class TestExtension(Extension):
+        extension_uri = "asdf://asdf-pydantic/examples/extensions/test-1.0.0"
+
+        converters = [AsdfPydanticConverter()]  # type: ignore
+        tags = [AsdfNode.get_tag_definition()]  # type: ignore
+
+    with asdf.config_context() as asdf_config:
+        asdf_config.add_resource_mapping(
+            {
+                yaml.safe_load(AsdfNode.model_asdf_schema())[
+                    "id"
+                ]: AsdfNode.model_asdf_schema()
+            }
+        )
+        asdf_config.add_extension(TestExtension())
+        yield asdf_config
+
+
+@pytest.mark.usefixtures("asdf_extension")
+def test_can_write_valid_asdf_file(tmp_path):
+    """Tests using the model to write an ASDF file validates its own schema."""
+    af = asdf.AsdfFile()
+    af["root"] = AsdfNode(name="foo", child=None)
+    af.validate()
+    af.write_to(tmp_path / "test.asdf")
+
+    with asdf.open(tmp_path / "test.asdf") as af:
+        assert af.tree
+
+
+@pytest.mark.usefixtures("asdf_extension")
+def test_errors_reading_invalid_asdf_file(tmp_path):
+    """Tests validation fails when ASDF file does not match the schema."""
+    content = """\
+        #ASDF 1.0.0
+        #ASDF_STANDARD 1.5.0
+        %YAML 1.1
+        %TAG ! tag:stsci.edu:asdf/
+        --- !core/asdf-1.1.0
+        asdf_library: !core/software-1.0.0 {author: The ASDF Developers, homepage: 'http://github.com/asdf-format/asdf',
+            name: asdf, version: 3.4.0}
+        history:
+            extensions:
+            - !core/extension_metadata-1.0.0
+                extension_class: asdf.extension._manifest.ManifestExtension
+                extension_uri: asdf://asdf-format.org/core/extensions/core-1.5.0
+                manifest_software: !core/software-1.0.0 {name: asdf_standard, version: 1.1.1}
+                software: !core/software-1.0.0 {name: asdf, version: 3.4.0}
+            - !core/extension_metadata-1.0.0 {extension_class: tests.examples.test_node.setup_module.<locals>.TestExtension,
+                extension_uri: 'asdf://asdf-pydantic/examples/extensions/test-1.0.0'}
+        root: !<asdf://asdf-pydantic/examples/tags/node-1.0.0>
+            child: None
+        ...
+    """
+    with open(tmp_path / "test.asdf", "wb") as f:
+        f.write(textwrap.dedent(content).encode("utf-8"))
+
+    with pytest.raises(asdf.exceptions.ValidationError):
+        with asdf.open(tmp_path / "test.asdf") as af:
+            assert af.tree