gson-comments/gson/src/test/java/com/google/gson/functional/StringTest.java

package com.google.gson.functional;

import com.google.gson.Gson;
import com.google.gson.JsonParseException;

import junit.framework.TestCase;

/**
 * Functional tests for Json serialization and deserialization of strings.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 */
public class StringTest extends TestCase {
  private Gson gson;

  @Override
  protected void setUp() throws Exception {
    super.setUp();
    gson = new Gson();
  }
  
  public void testStringValueSerialization() throws Exception {
    String value = "someRandomStringValue";
    assertEquals('"' + value + '"', gson.toJson(value));
  }

  public void testStringValueDeserialization() throws Exception {
    String value = "someRandomStringValue";
    String actual = gson.fromJson("\"" + value + "\"", String.class);
    assertEquals(value, actual);
  }

  public void testSingleQuoteInStringSerialization() throws Exception {
    String valueWithQuotes = "beforeQuote'afterQuote";
    String jsonRepresentation = gson.toJson(valueWithQuotes);
    assertEquals(valueWithQuotes, gson.fromJson(jsonRepresentation, String.class));
  }

  public void testEscapedCtrlNInStringSerialization() throws Exception {
    String value = "a\nb";
    String json = gson.toJson(value);
    assertEquals("\"a\\nb\"", json);
  }

  public void testEscapedCtrlNInStringDeserialization() throws Exception {
    String json = "'a\\nb'";
    String actual = gson.fromJson(json, String.class);
    assertEquals("a\nb", actual);
  }

  public void testEscapedCtrlRInStringSerialization() throws Exception {
    String value = "a\rb";
    String json = gson.toJson(value);
    assertEquals("\"a\\rb\"", json);
  }

  public void testEscapedCtrlRInStringDeserialization() throws Exception {
    String json = "'a\\rb'";
    String actual = gson.fromJson(json, String.class);
    assertEquals("a\rb", actual);
  }

  public void testEscapedBackslashInStringSerialization() throws Exception {
    String value = "a\\b";
    String json = gson.toJson(value);
    assertEquals("\"a\\\\b\"", json);
  }

  public void testEscapedBackslashInStringDeserialization() throws Exception {
    String actual = gson.fromJson("'a\\\\b'", String.class);
    assertEquals("a\\b", actual);
  }

  public void testSingleQuoteInStringDeserialization() throws Exception {
    String value = "beforeQuote'afterQuote";
    String actual = gson.fromJson("\"" + value + "\"", String.class);
    assertEquals(value, actual);
  }

  public void testEscapingQuotesInStringSerialization() throws Exception {
    String valueWithQuotes = "beforeQuote\"afterQuote";
    String jsonRepresentation = gson.toJson(valueWithQuotes);
    String target = gson.fromJson(jsonRepresentation, String.class);
    assertEquals(valueWithQuotes, target);
  }

  public void testEscapingQuotesInStringDeserialization() throws Exception {
    String value = "beforeQuote\\\"afterQuote";
    String actual = gson.fromJson("\"" + value + "\"", String.class);
    String expected = "beforeQuote\"afterQuote";
    assertEquals(expected, actual);
  }

  public void testStringValueAsSingleElementArraySerialization() throws Exception {
    String[] target = {"abc"};
    assertEquals("[\"abc\"]", gson.toJson(target));
    assertEquals("[\"abc\"]", gson.toJson(target, String[].class));
  }

  public void testStringValueAsSingleElementArrayDeserialization() throws Exception {
    String value = "someRandomStringValue";
    String actual = gson.fromJson("[\"" + value + "\"]", String.class);
    assertEquals(value, actual);
  }

  public void testReallyLongStringsDeserialization() throws Exception {
    StringBuilder sb = new StringBuilder(8096);
    sb.append("Once upon a time there was a really long string that caused a StackOverFlowError\n");
    sb.append("and now it is fixed and instead throws a JsonParserException.....Yippie!!!\n");
    sb.append("Wow....that is a really long string that is meant to be an exception stack trace, ");
    sb.append("but is not :( \n\n\n\n\n\n.");
    sb.append("lalalalala \n\n\n.");
    sb.append("C'est la vie!!! \n\n\n\n\n");

    for (int i = 0; i < 10; i++) {
      sb.append(sb.toString());
    }

    while (true) {
      try {
        String stackTrace = sb.toString();
        sb.append(stackTrace);
        String json = "{\"message\":\"Error message.\","
          + "\"stackTrace\":\"" + stackTrace + "\"}";
        parseLongJson(json);
      } catch (JsonParseException expected) {
        break;
      }
    }
  }
  
  private void parseLongJson(String json) throws JsonParseException {
    ExceptionHolder target = gson.fromJson(json, ExceptionHolder.class);
    assertTrue(target.message.contains("Error"));
    assertTrue(target.stackTrace.contains("Yippie"));
  }

  private static class ExceptionHolder {
    public final String message;
    public final String stackTrace;
    public ExceptionHolder() {
      this("", "");
    }
    public ExceptionHolder(String message, String stackTrace) {
      this.message = message;
      this.stackTrace = stackTrace;
    }
  }
}