Fix well formed exception (#1105)

The previous exception was styled in the following way:
... ["DATE']...
This commit will fix the different quote marks and replace the " with '

Author: StefMa

extras/src/main/java/com/google/gson/typeadapters/UtcDateTypeAdapter.java

@@ -229,7 +229,7 @@ private static Date parse(String date, ParsePosition pos) throws ParseException
     } catch (IllegalArgumentException e) {
       fail = e;
     }
-    String input = (date == null) ? null : ('"' + date + "'");
+    String input = (date == null) ? null : ("'" + date + "'");
     throw new ParseException("Failed to parse date [" + input + "]: " + fail.getMessage(), pos.getIndex());
   }
 

extras/src/test/java/com/google/gson/typeadapters/PostConstructAdapterFactoryTest.java

@@ -22,7 +22,6 @@
 import com.google.gson.GsonBuilder;
 
 import junit.framework.TestCase;
-import org.junit.Assert;
 
 import java.util.Arrays;
 import java.util.List;
@@ -50,10 +49,10 @@ public void testList() {
 
         // Throws NullPointerException without the fix in https://github.com/google/gson/pull/1103
         String json = gson.toJson(sandwiches);
-        Assert.assertEquals("{\"sandwiches\":[{\"bread\":\"white\",\"cheese\":\"cheddar\"},{\"bread\":\"whole wheat\",\"cheese\":\"swiss\"}]}", json);
+        assertEquals("{\"sandwiches\":[{\"bread\":\"white\",\"cheese\":\"cheddar\"},{\"bread\":\"whole wheat\",\"cheese\":\"swiss\"}]}", json);
 
         MultipleSandwiches sandwichesFromJson = gson.fromJson(json, MultipleSandwiches.class);
-        Assert.assertEquals(sandwiches, sandwichesFromJson);
+        assertEquals(sandwiches, sandwichesFromJson);
     }
 
     static class Sandwich {

extras/src/test/java/com/google/gson/typeadapters/UtcDateTypeAdapterTest.java

@@ -22,6 +22,7 @@
 import java.util.Locale;
 import java.util.TimeZone;
 
+import com.google.gson.JsonParseException;
 import junit.framework.TestCase;
 
 import com.google.gson.Gson;
@@ -76,4 +77,13 @@ public void testNullDateSerialization() {
     String json = gson.toJson(null, Date.class);
     assertEquals("null", json);
   }
+
+  public void testWellFormedParseException() {
+    try {
+      gson.fromJson("2017-06-20T14:32:30", Date.class);
+      fail("No exception");
+    } catch (JsonParseException exe) {
+      assertEquals(exe.getMessage(), "java.text.ParseException: Failed to parse date ['2017-06-20T14']: 2017-06-20T14");
+    }
+  }
 }