Issue #35

 - use the same char set when converting from characters to bytes and back again.
 - Remove usage of deprecated jsonFactory API in order to respect charset when printing to an OutputStream using the JsonJacksonFormat.
 - Added test class hierarchy to match production code hierarchy so tests do not need to be duplicated for each ProtobufFormatter.

Author: tonicsoft

src/main/java/com/googlecode/protobuf/format/JsonJacksonFormat.java

@@ -33,6 +33,7 @@ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
 import java.math.BigInteger;
 import java.nio.charset.Charset;
 import java.util.Iterator;
@@ -78,7 +79,7 @@ public class JsonJacksonFormat extends ProtobufFormatter {
      * original Protocol Buffer system)
      */
     public void print(final Message message, OutputStream output, Charset cs) throws IOException {
-        JsonGenerator generator = createGenerator(output);
+        JsonGenerator generator = createGenerator(output, cs);
     	print(message, generator);
     	generator.close();
     }
@@ -144,9 +145,12 @@ public void merge(JsonParser parser,
     }
 
 
-
     protected JsonGenerator createGenerator(OutputStream output) throws IOException {
-    	JsonGenerator generator = jsonFactory.createJsonGenerator(output, JsonEncoding.UTF8);
+        return createGenerator(output, Charset.forName(JsonEncoding.UTF8.getJavaName()));
+    }
+
+    private JsonGenerator createGenerator(OutputStream output, Charset cs) throws IOException {
+    	JsonGenerator generator = jsonFactory.createGenerator(new OutputStreamWriter(output, cs));
     	generator.disable(JsonGenerator.Feature.AUTO_CLOSE_TARGET);
     	return generator;
     }

src/main/java/com/googlecode/protobuf/format/ProtobufFormatter.java

@@ -88,7 +88,7 @@ public String printToString(final Message message) {
             ByteArrayOutputStream out = new ByteArrayOutputStream();
             print(message, out, defaultCharset);
             out.flush();
-            return out.toString();
+            return out.toString(defaultCharset.name());
         } catch (IOException e) {
             throw new RuntimeException("Writing to a StringBuilder threw an IOException (should never happen).",
                                        e);

src/test/java/com/googlecode/protobuf/format/JsonFormatTest.java

@@ -25,7 +25,7 @@
  * @author scr on 10/13/15.
  */
 @Test
-public class JsonFormatTest {
+public class JsonFormatTest extends ProtobufFormatterTest<JsonFormat> {
     private static final String RESOURCE_PATH = "/expectations/JsonFormatTest/";
     private static final FormatFactory FORMAT_FACTORY = new FormatFactory();
     private static final JsonFormat JSON_FORMATTER =
@@ -35,6 +35,11 @@ private static String getExpected(String name) throws IOException {
         return Files.readFile(JsonFormatTest.class.getResourceAsStream(RESOURCE_PATH + name)).trim();
     }
 
+    @Override
+    protected JsonFormat getFormatterUnderTest() {
+        return new JsonFormat();
+    }
+
     @DataProvider(name = "data")
     public static Object[][] data() throws IOException {
         return new Object[][]{

src/test/java/com/googlecode/protobuf/format/JsonJacksonFormatTest.java

@@ -21,9 +21,14 @@
  * @author scr on 10/13/15.
  */
 @Test
-public class JsonJacksonFormatTest {
+public class JsonJacksonFormatTest extends ProtobufFormatterTest<JsonJacksonFormat> {
     private static final JsonFactory JSON_FACTORY = new JsonFactory();
 
+    @Override
+    protected JsonJacksonFormat getFormatterUnderTest() {
+        return new JsonJacksonFormat();
+    }
+
     @Test
     public void testPrettyPrint() throws Exception {
         StringWriter writer = new StringWriter();

src/test/java/com/googlecode/protobuf/format/ProtobufFormatterTest.java

@@ -0,0 +1,52 @@
+package com.googlecode.protobuf.format;
+
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Test;
+import protobuf_unittest.UnittestProto;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.testng.Assert.assertNotEquals;
+
+public abstract class ProtobufFormatterTest<T extends ProtobufFormatter> {
+    private T protobufFormatter;
+    private Charset platformDefaultCharset = Charset.defaultCharset();
+    private Charset nonDefaultCharset = Charset.forName("UTF-16");
+    private String testData = "A";
+    private final String testDataAsJson = "\"" + testData + "\"";
+    private UnittestProto.OneString testProto = UnittestProto.OneString.newBuilder().setData(testData).build();
+
+    protected abstract T getFormatterUnderTest();
+
+    @BeforeMethod
+    public void setUp() throws Exception {
+        protobufFormatter = getFormatterUnderTest();
+    }
+
+    @Test
+    public void validateTestSetUp() {
+        //test is redundant unless default and non default charsets produce different results
+        assertNotEquals(platformDefaultCharset, nonDefaultCharset);
+        byte[] nonDefaultBytes = testData.getBytes(nonDefaultCharset);
+        assertNotEquals(testData.getBytes(platformDefaultCharset), nonDefaultBytes);
+        assertNotEquals(testData, new String(nonDefaultBytes, platformDefaultCharset));
+    }
+
+    @Test
+    public void canSerialiseToBytesUsingNonDefaultCharset() throws IOException {
+        ByteArrayOutputStream output = new ByteArrayOutputStream();
+        protobufFormatter.print(testProto, output, nonDefaultCharset);
+        assertThat(output.toString(nonDefaultCharset.name()), containsString(testDataAsJson));
+    }
+
+    @Test
+    public void canSerialiseUsingNonDefaultCharSet() {
+        protobufFormatter.setDefaultCharset(nonDefaultCharset);
+        UnittestProto.OneString message = UnittestProto.OneString.newBuilder().setData(testData).build();
+        assertThat(protobufFormatter.printToString(message), containsString(testDataAsJson));
+    }
+}