diff --git a/gio/tests/unix-streams.c b/gio/tests/unix-streams.c
index 65eedb368..5ec829919 100644
--- a/gio/tests/unix-streams.c
+++ b/gio/tests/unix-streams.c
@@ -22,6 +22,7 @@
 #include <gio/gio.h>
 #include <gio/gunixinputstream.h>
 #include <gio/gunixoutputstream.h>
+#include <glib.h>
 #include <glib/glib-unix.h>
 #include <signal.h>
 #include <stdlib.h>
@@ -29,7 +30,8 @@
 #include <unistd.h>
 #include <fcntl.h>
 
-#define DATA "abcdefghijklmnopqrstuvwxyz"
+/* sizeof(DATA) will give the number of bytes in the array, plus the terminating nul */
+static const gchar DATA[] = "abcdefghijklmnopqrstuvwxyz";
 
 int writer_pipe[2], reader_pipe[2];
 GCancellable *writer_cancel, *reader_cancel, *main_cancel;
@@ -118,8 +120,8 @@ reader_thread (gpointer user_data)
   g_assert_not_reached ();
 }
 
-char main_buf[sizeof (DATA)];
-gssize main_len, main_offset;
+static char main_buf[sizeof (DATA)];
+static gssize main_len, main_offset;
 
 static void main_thread_read (GObject *source, GAsyncResult *res, gpointer user_data);
 static void main_thread_skipped (GObject *source, GAsyncResult *res, gpointer user_data);
diff --git a/glib/tests/autoptr.c b/glib/tests/autoptr.c
index 788d05c5e..cd510ed16 100644
--- a/glib/tests/autoptr.c
+++ b/glib/tests/autoptr.c
@@ -180,6 +180,7 @@ test_g_main_context_pusher (void)
   if (TRUE)
     {
       g_autoptr(GMainContextPusher) val = g_main_context_pusher_new (context);
+      g_assert_nonnull (val);
 
       /* Check it’s now the thread-default main context */
       g_assert_true (g_main_context_get_thread_default () == context);
diff --git a/gobject/tests/autoptr.c b/gobject/tests/autoptr.c
index 19421c220..ec3c89ebc 100644
--- a/gobject/tests/autoptr.c
+++ b/gobject/tests/autoptr.c
@@ -77,6 +77,7 @@ test_autoptr (void)
 
   {
     g_autoptr (TestAutoCleanup) tac = tac_ptr;
+    g_assert_nonnull (tac);
   }
 #ifdef __GNUC__
   g_assert_null (tac_ptr);