Enhancement: allow `expected` in json_match (and json_schema) to be a plain string, not just a ContentReference object

[snytkine]

Summary

Currently the expected field of a json_match assertion must be a ContentReference object with type and content properties:

assertions:
  - type: json_match
    path: response.body.json
    expected:
      type: inline
      content: '{"id": 1, "name": "Alice"}'

The request body already supports a shorthand where the value can be a plain string (treated as inline content):

body: '{"id": 1}'          # plain string — works today for request body

The same convenience should be available for json_match (and json_schema) expected:

assertions:
  - type: json_match
    path: response.body.json
    expected: '{"id": 1, "name": "Alice"}'   # plain string — desired shorthand

When expected is a plain string it should be treated as type: inline with the string as content and an empty ignore list.

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Note on Schema File Location

The authoritative YAML schema for test suites is src/main/resources/schemas/test-suite-schema.json — this is the file that is packaged with the application and used at runtime for validation. The file at .vscode/test-suite-schema.json is only a VS Code IDE helper copy and should not be edited directly.

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Changes Required

1. JSON Schema (src/main/resources/schemas/test-suite-schema.json)

Change the expected definition for json_match from a bare $ref:

"expected": {
  "$ref": "#/$defs/ContentReference"
}

to a oneOf that accepts either a plain string or the full ContentReference object:

"expected": {
  "oneOf": [
    {
      "type": "string",
      "description": "Inline expected JSON (shorthand — equivalent to type: inline)"
    },
    {
      "$ref": "#/$defs/ContentReference"
    }
  ]
}

Apply the same change to json_schema's expected field for consistency.

2. YAML Deserialization

ObjectExpectedValue is currently a plain Java record (String type, String content, List<String> ignore). Jackson deserializes it only from an object node.

Add a custom Jackson deserializer (or use @JsonCreator / JsonDeserializer) so that:

• A JSON string node → new ObjectExpectedValue("inline", theString, null)
• A JSON object node → existing field-by-field mapping (unchanged)

3. No evaluator changes needed

JsonMatchAssertionEvaluator and JsonSchemaAssertionEvaluator already handle type == "inline" correctly, so no changes are needed there once deserialization normalises the plain-string form into an ObjectExpectedValue.

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Files to Change

File	Change
src/main/resources/schemas/test-suite-schema.json	oneOf [string, ContentReference] for json_match and json_schema expected
src/main/java/.../model/ObjectExpectedValue.java	Add custom Jackson deserializer to handle plain-string shorthand
src/test/java/.../model/ObjectExpectedValueDeserializerTest.java (new)	Unit tests: plain string → ObjectExpectedValue("inline", …, null); object → normal mapping
src/test/java/.../service/TestSuiteLoaderTest.java	Integration test: suite YAML using plain-string expected loads correctly