test: add comprehensive regression tests for historical closed issues

Add 52 test cases covering 44 closed GitHub issues across 10 categories:
- Circular reference handling (9 tests)
- Root-level $ref resolution (8 tests)
- Bundle operations (4 tests)
- Dereference operations (4 tests)
- JSON Pointer handling (5 tests)
- External references (2 tests)
- Error handling (2 tests)
- And 6 more categories

Tests validate the current behavior of fixed issues and document
expected behavior for issues that remain open. Includes 12 fixture
files for testing external file resolution and complex schemas.

All tests pass. Full test suite: 350 tests passing, 6 skipped.

Author: jonluca

test/specs/historical-issues/fixtures/bar.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "definitions": {
+    "bardef": { "type": "string" }
+  }
+}

test/specs/historical-issues/fixtures/base-200.json

@@ -0,0 +1,6 @@
+{
+  "type": "object",
+  "properties": {
+    "some_value": { "$ref": "defs.json#/definitions/astring" }
+  }
+}

test/specs/historical-issues/fixtures/binary-tag.yaml

@@ -0,0 +1,8 @@
+Person:
+  type: object
+  properties:
+    name:
+      type: string
+    data:
+      type: string
+      default: "base64data"

test/specs/historical-issues/fixtures/color.json

@@ -0,0 +1,4 @@
+{
+  "type": "string",
+  "enum": ["red", "green", "blue"]
+}

test/specs/historical-issues/fixtures/common.yaml

@@ -0,0 +1,9 @@
+components:
+  schemas:
+    ErrorResponse:
+      type: object
+      properties:
+        message:
+          type: string
+        code:
+          type: integer

test/specs/historical-issues/fixtures/defs.json

@@ -0,0 +1,7 @@
+{
+  "definitions": {
+    "astring": {
+      "$ref": "defs2.json#/definitions/bstring"
+    }
+  }
+}

test/specs/historical-issues/fixtures/defs2.json

@@ -0,0 +1,9 @@
+{
+  "definitions": {
+    "bstring": {
+      "type": "string",
+      "minLength": 1,
+      "maxLength": 100
+    }
+  }
+}

test/specs/historical-issues/fixtures/foo.json

@@ -0,0 +1,12 @@
+{
+  "$schema": "http://json-schema.org/draft-04/schema#",
+  "definitions": {
+    "foodef": { "$ref": "bar.json#/definitions/bardef" }
+  },
+  "type": "object",
+  "properties": {
+    "prop": {
+      "$ref": "#/definitions/foodef"
+    }
+  }
+}

test/specs/historical-issues/fixtures/linked-list-schema.json

@@ -0,0 +1,14 @@
+{
+  "$id": "LinkedList.schema.json",
+  "definitions": {
+    "linkedList": {
+      "type": "object",
+      "properties": {
+        "head": {
+          "description": "The head of the list",
+          "$ref": "node-schema.json#/definitions/node"
+        }
+      }
+    }
+  }
+}

test/specs/historical-issues/fixtures/node-schema.json

@@ -0,0 +1,17 @@
+{
+  "$id": "Node.schema.json",
+  "definitions": {
+    "node": {
+      "type": "object",
+      "properties": {
+        "data": {
+          "description": "Some data",
+          "type": "integer"
+        },
+        "next": {
+          "$ref": "#/definitions/node"
+        }
+      }
+    }
+  }
+}