diff --git a/testsuite/gtk/expression.c b/testsuite/gtk/expression.c
index 8c6754fe63..663e0fcbaf 100644
--- a/testsuite/gtk/expression.c
+++ b/testsuite/gtk/expression.c
@@ -48,13 +48,17 @@ test_property (void)
 
   gtk_string_filter_set_search (filter, "Hello World");
   g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
   g_assert (gtk_expression_evaluate (expr, filter , &value));
   g_assert_cmpstr (g_value_get_string (&value), ==, "Hello World");
   g_value_unset (&value);
 
+  gtk_expression_watch_unwatch (watch);
+  g_assert_cmpint (counter, ==, 0);
+
   gtk_expression_unref (expr);
   g_object_unref (filter);
-  gtk_expression_watch_unwatch (watch);
 }
 
 static char *
@@ -116,9 +120,298 @@ test_closure (void)
   g_assert_cmpstr (g_value_get_string (&value), ==, "OK");
   g_value_unset (&value);
 
+  gtk_expression_watch_unwatch (watch);
+  g_assert_cmpint (counter, ==, 5);
+
   gtk_expression_unref (expr);
   g_object_unref (filter);
+}
+
+static void
+test_constant (void)
+{
+  GtkExpression *expr;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+
+  expr = gtk_constant_expression_new (G_TYPE_INT, 22);
+  g_assert_cmpint (gtk_expression_get_value_type (expr), ==, G_TYPE_INT);
+  g_assert_true (gtk_expression_is_static (expr));
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_cmpint (g_value_get_int (&value), ==, 22);
+
+  gtk_expression_unref (expr);
+}
+
+/* Test that object expressions fail to evaluate when
+ * the object is gone.
+ */
+static void
+test_object (void)
+{
+  GtkExpression *expr;
+  GObject *obj;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+
+  obj = G_OBJECT (gtk_string_filter_new ());
+
+  expr = gtk_object_expression_new (obj);
+  g_assert_true (!gtk_expression_is_static (expr));
+  g_assert_cmpint (gtk_expression_get_value_type (expr), ==, GTK_TYPE_STRING_FILTER);
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_true (g_value_get_object (&value) == obj);
+  g_value_unset (&value);
+
+  g_clear_object (&obj);
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_false (res);
+
+  gtk_expression_unref (expr);
+}
+
+/* Some basic tests that nested expressions work; in particular test
+ * that watching works when things change deeper in the expression tree
+ *
+ * The setup we use is GtkFilterListModel -> GtkFilter -> "search" property,
+ * which gives us an expression tree like
+ *
+ * GtkPropertyExpression "search"
+ *    -> GtkPropertyExpression "filter"
+ *         -> GtkObjectExpression listmodel
+ *
+ * We test setting both the search property and the filter property.
+ */
+static void
+test_nested (void)
+{
+  GtkExpression *list_expr;
+  GtkExpression *filter_expr;
+  GtkExpression *expr;
+  GtkFilter *filter;
+  GListModel *list;
+  GtkFilterListModel *filtered;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+  GtkExpressionWatch *watch;
+  guint counter = 0;
+
+  filter = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "word");
+  list = G_LIST_MODEL (g_list_store_new (G_TYPE_OBJECT));
+  filtered = gtk_filter_list_model_new (list, filter);
+
+  list_expr = gtk_object_expression_new (G_OBJECT (filtered));
+  filter_expr = gtk_property_expression_new (GTK_TYPE_FILTER_LIST_MODEL, list_expr, "filter");
+  expr = gtk_property_expression_new (GTK_TYPE_STRING_FILTER, filter_expr, "search");
+
+  g_assert_true (!gtk_expression_is_static (expr));
+  g_assert_cmpint (gtk_expression_get_value_type (expr), ==, G_TYPE_STRING);
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "word");
+  g_value_unset (&value);
+
+  watch = gtk_expression_watch (expr, NULL, inc_counter, &counter, NULL);
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "salad");
+  g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "salad");
+  g_value_unset (&value);
+
+  gtk_filter_list_model_set_filter (filtered, filter);
+  g_assert_cmpint (counter, ==, 0);
+
+  g_clear_object (&filter);
+  filter = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "salad");
+  gtk_filter_list_model_set_filter (filtered, filter);
+  g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "salad");
+  g_value_unset (&value);
+
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "bar");
+  g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "bar");
+  g_value_unset (&value);
+
+  gtk_filter_list_model_set_filter (filtered, NULL);
+  g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_false (res);
+
   gtk_expression_watch_unwatch (watch);
+  g_assert_cmpint (counter, ==, 0);
+
+  g_object_unref (filtered);
+  g_object_unref (list);
+  g_object_unref (filter);
+  gtk_expression_unref (expr);
+}
+
+/* This test uses the same setup as the last test, but
+ * passes the filter as the "this" object when creating
+ * the watch.
+ *
+ * So when we set a new filter and the old one gets desroyed,
+ * the watch should invalidate itself because its this object
+ * is gone.
+ */
+static void
+test_nested_this_destroyed (void)
+{
+  GtkExpression *list_expr;
+  GtkExpression *filter_expr;
+  GtkExpression *expr;
+  GtkFilter *filter;
+  GListModel *list;
+  GtkFilterListModel *filtered;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+  GtkExpressionWatch *watch;
+  guint counter = 0;
+
+  filter = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "word");
+  list = G_LIST_MODEL (g_list_store_new (G_TYPE_OBJECT));
+  filtered = gtk_filter_list_model_new (list, filter);
+
+  list_expr = gtk_object_expression_new (G_OBJECT (filtered));
+  filter_expr = gtk_property_expression_new (GTK_TYPE_FILTER_LIST_MODEL, list_expr, "filter");
+  expr = gtk_property_expression_new (GTK_TYPE_STRING_FILTER, filter_expr, "search");
+
+  watch = gtk_expression_watch (expr, filter, inc_counter, &counter, NULL);
+  gtk_expression_watch_ref (watch);
+  res = gtk_expression_watch_evaluate (watch, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "word");
+  g_value_unset (&value);
+
+  g_clear_object (&filter);
+  g_assert_cmpint (counter, ==, 0);
+
+  filter = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "salad");
+  gtk_filter_list_model_set_filter (filtered, filter);
+  g_assert_cmpint (counter, ==, 1);
+  counter = 0;
+
+  res = gtk_expression_watch_evaluate (watch, &value);
+  g_assert_false (res);
+
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "bar");
+  g_assert_cmpint (counter, ==, 0);
+
+  gtk_filter_list_model_set_filter (filtered, NULL);
+  g_assert_cmpint (counter, ==, 0);
+
+  res = gtk_expression_watch_evaluate (watch, &value);
+  g_assert_false (res);
+  g_assert_false (G_IS_VALUE (&value));
+
+  /* We unwatch on purpose here to make sure it doesn't do bad things. */
+  gtk_expression_watch_unwatch (watch);
+  gtk_expression_watch_unref (watch);
+  g_assert_cmpint (counter, ==, 0);
+
+  g_object_unref (filtered);
+  g_object_unref (list);
+  g_object_unref (filter);
+  gtk_expression_unref (expr);
+}
+
+/* Test that property expressions fail to evaluate if the
+ * expression evaluates to an object of the wrong type
+ */
+static void
+test_type_mismatch (void)
+{
+  GtkFilter *filter;
+  GtkExpression *expr;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+
+  filter = gtk_any_filter_new ();
+
+  expr = gtk_property_expression_new (GTK_TYPE_STRING_FILTER, gtk_constant_expression_new (GTK_TYPE_ANY_FILTER, filter), "search");
+
+  res = gtk_expression_evaluate (expr, NULL, &value);
+  g_assert_false (res);
+  g_assert_false (G_IS_VALUE (&value));
+
+  gtk_expression_unref (expr);
+  g_object_unref (filter);
+}
+
+/* Some basic tests around 'this' */
+static void
+test_this (void)
+{
+  GtkFilter *filter;
+  GtkFilter *filter2;
+  GtkExpression *expr;
+  GValue value = G_VALUE_INIT;
+  gboolean res;
+
+  expr = gtk_property_expression_new (GTK_TYPE_STRING_FILTER, NULL, "search");
+
+  filter = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter), "word");
+
+  filter2 = gtk_string_filter_new ();
+  gtk_string_filter_set_search (GTK_STRING_FILTER (filter2), "sausage");
+
+  res = gtk_expression_evaluate (expr, filter, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "word");
+  g_value_unset (&value);
+
+  res = gtk_expression_evaluate (expr, filter2, &value);
+  g_assert_true (res);
+  g_assert_cmpstr (g_value_get_string (&value), ==, "sausage");
+  g_value_unset (&value);
+
+  gtk_expression_unref (expr);
+  g_object_unref (filter2);
+  g_object_unref (filter);
+}
+
+/* Check that even for static expressions, watches can be created
+ * and destroying the "this" argument does invalidate the
+ * expression.
+ */
+static void
+test_constant_watch_this_destroyed (void)
+{
+  GtkExpression *expr;
+  GObject *this;
+  guint counter = 0;
+
+  this = g_object_new (G_TYPE_OBJECT, NULL);
+  expr = gtk_constant_expression_new (G_TYPE_INT, 42);
+  gtk_expression_watch (expr, this, inc_counter, &counter, NULL);
+  g_assert_cmpint (counter, ==, 0);
+
+  g_clear_object (&this);
+  g_assert_cmpint (counter, ==, 1);
 }
 
 int
@@ -129,6 +422,13 @@ main (int argc, char *argv[])
 
   g_test_add_func ("/expression/property", test_property);
   g_test_add_func ("/expression/closure", test_closure);
+  g_test_add_func ("/expression/constant", test_constant);
+  g_test_add_func ("/expression/constant-watch-this-destroyed", test_constant_watch_this_destroyed);
+  g_test_add_func ("/expression/object", test_object);
+  g_test_add_func ("/expression/nested", test_nested);
+  g_test_add_func ("/expression/nested-this-destroyed", test_nested_this_destroyed);
+  g_test_add_func ("/expression/type-mismatch", test_type_mismatch);
+  g_test_add_func ("/expression/this", test_this);
 
   return g_test_run ();
 }