Add tests for ESJsonFactory

Author: jordan-powers

libs/x-content/impl/src/test/java/org/elasticsearch/xcontent/provider/json/ESJsonFactoryTests.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.xcontent.provider.json;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonParseException;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
+import com.fasterxml.jackson.core.json.ReaderBasedJsonParser;
+import com.fasterxml.jackson.core.json.UTF8StreamJsonParser;
+
+import org.elasticsearch.test.ESTestCase;
+import org.hamcrest.Matchers;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+
+public class ESJsonFactoryTests extends ESTestCase {
+
+    public void testCreateParser() throws IOException {
+        JsonFactory factory = new ESJsonFactoryBuilder().build();
+        assertThat(factory, Matchers.instanceOf(ESJsonFactory.class));
+
+        // \ufeff is the BOM
+        String[] inputs = { "{\"foo\": \"bar\"}", "\ufeff{\"foo\": \"bar\"}" };
+        Charset[] charsets = { StandardCharsets.UTF_8, StandardCharsets.UTF_16LE, StandardCharsets.UTF_16BE };
+        Class<?>[] expectedParsers = { ESUTF8StreamJsonParser.class, ReaderBasedJsonParser.class, ReaderBasedJsonParser.class };
+
+        for (String input : inputs) {
+            for (int i = 0; i < charsets.length; i++) {
+                ByteBuffer encoded = charsets[i].encode(input);
+                JsonParser parser = factory.createParser(encoded.array());
+                assertThat(parser, Matchers.instanceOf(expectedParsers[i]));
+                assertThat(parser.nextToken(), Matchers.equalTo(JsonToken.START_OBJECT));
+                assertThat(parser.nextFieldName(), Matchers.equalTo("foo"));
+                assertThat(parser.nextValue(), Matchers.equalTo(JsonToken.VALUE_STRING));
+                assertThat(parser.getValueAsString(), Matchers.equalTo("bar"));
+            }
+        }
+
+        // Valid BOM
+        {
+            JsonParser parser = factory.createParser(new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBF, '{', '}' });
+            assertThat(parser, Matchers.instanceOf(ESUTF8StreamJsonParser.class));
+            assertThat(parser.nextToken(), Matchers.equalTo(JsonToken.START_OBJECT));
+        }
+
+        // Invalid BOMs
+        {
+            JsonParser parser = factory.createParser(new byte[] { (byte) 0xEF, (byte) 0xBB, (byte) 0xBB, '{', '}' });
+            assertThat(parser, Matchers.instanceOf(UTF8StreamJsonParser.class));
+            assertThrows("Invalid UTF-8 start byte 0xbb", JsonParseException.class, parser::nextToken);
+        }
+
+        {
+            JsonParser parser = factory.createParser(new byte[] { (byte) 0xEF, '{', '}' });
+            assertThat(parser, Matchers.instanceOf(UTF8StreamJsonParser.class));
+            assertThrows("Invalid UTF-8 start byte 0x7b", JsonParseException.class, parser::nextToken);
+        }
+    }
+}