test(representation): add test suite for JSON String rep

Author: char0n

src/representation/json-string.js

@@ -1,10 +1,10 @@
-const to = (jsonPointer) => {
+export const to = (jsonPointer) => {
   return JSON.stringify(jsonPointer);
 };
 
-const from = (jsonString) => {
+export const from = (jsonString) => {
   try {
-    return JSON.parse(jsonString);
+    return String(JSON.parse(jsonString));
   } catch {
     return jsonString;
   }

test/representation/json-string.js

@@ -0,0 +1,66 @@
+import { assert } from 'chai';
+
+import { JSONString } from '../../src/index.js';
+
+describe('JSON String Representation (isomorphic behavior)', function () {
+  it('should preserve identity under to() and from() (RFC 6901)', function () {
+    const pointers = [
+      '',
+      '/foo',
+      '/foo/0',
+      '/',
+      '/a~1b',
+      '/c%d',
+      '/e^f',
+      '/g|h',
+      '/i\\j',
+      '/k"l',
+      '/ ',
+      '/m~0n',
+    ];
+
+    pointers.forEach((pointer) => {
+      const jsonString = JSONString.to(pointer);
+      const decodedPointer = JSONString.from(jsonString);
+      assert.strictEqual(decodedPointer, pointer, `Failed for pointer: ${pointer}`);
+    });
+  });
+
+  context('edge cases', function () {
+    specify('should handle empty string conversion', function () {
+      assert.strictEqual(JSONString.to(''), '""');
+      assert.strictEqual(JSONString.from('""'), '');
+    });
+
+    specify('should handle special characters correctly', function () {
+      assert.strictEqual(JSONString.to('/foo"bar'), '"/foo\\"bar"'); // escape quotes
+      assert.strictEqual(JSONString.from('"/foo\\"bar"'), '/foo"bar');
+
+      assert.strictEqual(JSONString.to('/back\\slash'), '"/back\\\\slash"'); // escape backslash
+      assert.strictEqual(JSONString.from('"/back\\\\slash"'), '/back\\slash');
+    });
+
+    specify('should handle unicode characters correctly', function () {
+      assert.strictEqual(JSONString.to('/😀'), '"/😀"');
+      assert.strictEqual(JSONString.from('"/😀"'), '/😀');
+    });
+
+    specify('should return original string if `from()` is given malformed JSON', function () {
+      assert.strictEqual(JSONString.from('not a json string'), 'not a json string');
+      assert.strictEqual(JSONString.from('{invalid:json}'), '{invalid:json}');
+      assert.strictEqual(JSONString.from('42'), '42');
+    });
+
+    specify('should correctly handle deeply nested JSON Pointers', function () {
+      const nestedPointer = '/foo/bar/baz/qux/quux/corge/grault/garply/waldo/fred';
+      const jsonString = JSONString.to(nestedPointer);
+      const decodedPointer = JSONString.from(jsonString);
+      assert.strictEqual(decodedPointer, nestedPointer);
+    });
+
+    specify('should preserve leading and trailing spaces', function () {
+      assert.strictEqual(JSONString.to(' /foo/bar '), '" /foo/bar "');
+      assert.strictEqual(JSONString.from('" /foo/bar "'), ' /foo/bar ');
+    });
+  });
+});