diff --git a/gio/ChangeLog b/gio/ChangeLog
index ba94549f5..faf85aea9 100644
--- a/gio/ChangeLog
+++ b/gio/ChangeLog
@@ -1,3 +1,17 @@
+2008-06-29  Matthias Clasen  <mclasen@redhat.com>
+
+	* tests/Makefile.am: 
+	* tests/memory-output-stream.c: Add some tests for
+	GMemoryOutputStream. 
+
+2008-06-29  Matthias Clasen  <mclasen@redhat.com>
+
+	Bug 540423 – unrecoverable error after g_seekable_truncate(seekable,
+	0, ...)
+
+	* gmemoryoutputstream.c (array_resize): Handle truncation to
+	zero correctly. Reported by Akira Tagoh
+
 2008-06-29  Matthias Clasen  <mclasen@redhat.com>
 
 	* gmemoryoutputstream.c: Trivial doc fixes
diff --git a/gio/gmemoryoutputstream.c b/gio/gmemoryoutputstream.c
index 9349e229b..ebb91ab3c 100644
--- a/gio/gmemoryoutputstream.c
+++ b/gio/gmemoryoutputstream.c
@@ -326,7 +326,7 @@ array_resize (GMemoryOutputStream  *ostream,
   len = priv->len;
   data = priv->realloc_fn (priv->data, size);
 
-  if (!data) 
+  if (size > 0 && !data) 
     {
       if (allow_partial &&
 	  priv->pos < priv->len)
diff --git a/gio/tests/Makefile.am b/gio/tests/Makefile.am
index 6f3c65025..308dbd6d3 100644
--- a/gio/tests/Makefile.am
+++ b/gio/tests/Makefile.am
@@ -16,15 +16,24 @@ progs_ldadd     = 					\
 	$(top_builddir)/gio/libgio-2.0.la
 
 
-TEST_PROGS       += memory-input-stream g-file g-file-info data-input-stream data-output-stream
+TEST_PROGS +=	 		\
+	memory-input-stream 	\
+	memory-output-stream 	\
+	g-file 			\
+	g-file-info 		\
+	data-input-stream 	\
+	data-output-stream
 
 if OS_UNIX
-TEST_PROGS       += live-g-file
+TEST_PROGS += live-g-file
 endif
 
 memory_input_stream_SOURCES	  = memory-input-stream.c
 memory_input_stream_LDADD	  = $(progs_ldadd)
 
+memory_output_stream_SOURCES	  = memory-output-stream.c
+memory_output_stream_LDADD	  = $(progs_ldadd)
+
 g_file_SOURCES	  = g-file.c
 g_file_LDADD	  = $(progs_ldadd)
 
diff --git a/gio/tests/memory-output-stream.c b/gio/tests/memory-output-stream.c
new file mode 100644
index 000000000..f0b5ff501
--- /dev/null
+++ b/gio/tests/memory-output-stream.c
@@ -0,0 +1,91 @@
+/* GLib testing framework examples and tests
+ * Copyright (C) 2008 Red Hat, Inc.
+ * Author: Matthias Clasen
+ *
+ * This work is provided "as is"; redistribution and modification
+ * in whole or in part, in any medium, physical or electronic is
+ * permitted without restriction.
+ *
+ * This work is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * In no event shall the authors or contributors be liable for any
+ * direct, indirect, incidental, special, exemplary, or consequential
+ * damages (including, but not limited to, procurement of substitute
+ * goods or services; loss of use, data, or profits; or business
+ * interruption) however caused and on any theory of liability, whether
+ * in contract, strict liability, or tort (including negligence or
+ * otherwise) arising in any way out of the use of this software, even
+ * if advised of the possibility of such damage.
+ */
+#include <glib/glib.h>
+#include <gio/gio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static void
+test_truncate (void)
+{
+  GOutputStream *mo;
+  GDataOutputStream *o;
+  int i;
+  GError *error = NULL;
+
+  g_test_bug ("540423");
+
+  mo = g_memory_output_stream_new (NULL, 0, g_realloc, g_free);
+  o = g_data_output_stream_new (mo);
+  for (i = 0; i < 1000; i++)
+    {
+      g_data_output_stream_put_byte (o, 1, NULL, &error);
+      g_assert (error == NULL);
+    }
+  g_seekable_truncate (G_SEEKABLE (mo), 0, NULL, &error);
+  g_assert (error == NULL);
+  for (i = 0; i < 2000; i++)
+    {
+      g_data_output_stream_put_byte (o, 1, NULL, &error);
+      g_assert (error == NULL);
+    }
+
+  g_object_unref (o);
+  g_object_unref (mo);
+}
+
+static void
+test_data_size (void)
+{
+  GOutputStream *mo;
+  GDataOutputStream *o;
+  int pos;
+
+  g_test_bug ("540459");
+
+  mo = g_memory_output_stream_new (NULL, 0, g_realloc, g_free);
+  o = g_data_output_stream_new (mo);
+  g_data_output_stream_put_byte (o, 1, NULL, NULL);
+  pos = g_memory_output_stream_get_data_size (G_MEMORY_OUTPUT_STREAM (mo));
+  g_assert_cmpint (pos, ==, 1);
+
+  g_seekable_seek (G_SEEKABLE (mo), 0, G_SEEK_CUR, NULL, NULL);
+  pos = g_seekable_tell (G_SEEKABLE (mo));
+  g_assert_cmpint (pos, ==, 1);
+
+  g_object_unref (o);
+  g_object_unref (mo);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  g_type_init ();
+  g_test_init (&argc, &argv, NULL);
+  g_test_bug_base ("http://bugzilla.gnome.org/");
+
+  g_test_add_func ("/memory-output-stream/truncate", test_truncate);
+  g_test_add_func ("/memory-output-stream/get-data-size", test_data_size);
+
+  return g_test_run();
+}