fix: escape keys in JSON paths and add test for patternProperties

closes #22

Author: ivangsa

src/main/java/io/zenwave360/jsonrefparser/$RefParser.java

@@ -418,7 +418,11 @@ protected Resolver getResolver(RefFormat refFormat, URI currentURL) {
     }
 
     private String jsonPath(String[] paths) {
-        return "$" + Arrays.stream(paths).map(path -> "['" + path + "']").collect(Collectors.joining());
+        return "$" + Arrays.stream(paths).map(path -> "['" + escapeKey(path) + "']").collect(Collectors.joining());
+    }
+
+    private String escapeKey(String key) {
+        return key.replace("\\", "\\\\").replace("'", "\\'");
     }
 
     private String jsonPointer(String[] paths) {

src/test/java/io/zenwave360/jsonrefparser/GH22Test.java

@@ -0,0 +1,51 @@
+package io.zenwave360.jsonrefparser;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Map;
+
+public class GH22Test {
+
+    private static final ObjectMapper mapper = new ObjectMapper();
+
+    @Test
+    public void testLocalSchemaWithPatternProperties() throws IOException {
+        File file = new File("src/test/resources/schema-with-pattern-properties.json");
+        final var parser = new $RefParser(file);
+        final var schema = parser
+                .parse()
+                .dereference()
+                .mergeAllOf()
+                .getRefs().schema();
+
+        Assert.assertNotNull(schema);
+
+        // Verify the schema has the expected structure
+        Assert.assertTrue(schema.containsKey("properties"));
+        Assert.assertTrue(schema.containsKey("patternProperties"));
+        Assert.assertTrue(schema.containsKey("definitions"));
+
+        // Verify patternProperties contains the expected pattern
+        Map<String, Object> patternProperties = (Map<String, Object>) schema.get("patternProperties");
+        Assert.assertTrue(patternProperties.containsKey("^x-[\\w\\d\\.\\x2d_]+$"));
+
+        // Verify the pattern property has been dereferenced (should contain the extension definition)
+        Map<String, Object> extensionPattern = (Map<String, Object>) patternProperties.get("^x-[\\w\\d\\.\\x2d_]+$");
+        Assert.assertNotNull(extensionPattern);
+        Assert.assertEquals("Any property starting with x- is valid.", extensionPattern.get("description"));
+
+        // Verify nested patternProperties in info definition
+        Map<String, Object> definitions = (Map<String, Object>) schema.get("definitions");
+        Map<String, Object> infoDefinition = (Map<String, Object>) definitions.get("info");
+        Map<String, Object> infoPatternProperties = (Map<String, Object>) infoDefinition.get("patternProperties");
+        Assert.assertTrue(infoPatternProperties.containsKey("^x-[\\w\\d\\.\\x2d_]+$"));
+
+        // Print the schema for debugging
+//        System.out.println("Dereferenced schema:");
+//        System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(schema));
+    }
+}

src/test/resources/schema-with-pattern-properties.json

@@ -0,0 +1,82 @@
+{
+  "$id": "http://example.com/schemas/test-schema.json",
+  "$schema": "http://json-schema.org/draft-07/schema",
+  "title": "Test Schema with Pattern Properties",
+  "type": "object",
+  "required": [
+    "name",
+    "info"
+  ],
+  "additionalProperties": false,
+  "patternProperties": {
+    "^x-[\\w\\d\\.\\x2d_]+$": {
+      "$ref": "#/definitions/extension"
+    }
+  },
+  "properties": {
+    "name": {
+      "type": "string",
+      "description": "The name of the object."
+    },
+    "info": {
+      "$ref": "#/definitions/info"
+    },
+    "metadata": {
+      "$ref": "#/definitions/metadata"
+    }
+  },
+  "definitions": {
+    "extension": {
+      "description": "Any property starting with x- is valid.",
+      "additionalProperties": true,
+      "additionalItems": true
+    },
+    "info": {
+      "type": "object",
+      "required": [
+        "version",
+        "title"
+      ],
+      "additionalProperties": false,
+      "patternProperties": {
+        "^x-[\\w\\d\\.\\x2d_]+$": {
+          "$ref": "#/definitions/extension"
+        }
+      },
+      "properties": {
+        "title": {
+          "type": "string",
+          "description": "A unique and precise title."
+        },
+        "version": {
+          "type": "string",
+          "description": "A semantic version number."
+        },
+        "description": {
+          "type": "string",
+          "description": "A longer description."
+        }
+      }
+    },
+    "metadata": {
+      "type": "object",
+      "additionalProperties": false,
+      "patternProperties": {
+        "^x-[\\w\\d\\.\\x2d_]+$": {
+          "$ref": "#/definitions/extension"
+        }
+      },
+      "properties": {
+        "created": {
+          "type": "string",
+          "format": "date-time"
+        },
+        "updated": {
+          "type": "string",
+          "format": "date-time"
+        }
+      }
+    }
+  }
+}
+