diff --git a/tests/dibi/DibiConnection.substitutions.phpt b/tests/dibi/DibiConnection.substitutions.phpt
index 236c860a..caa4b782 100644
--- a/tests/dibi/DibiConnection.substitutions.phpt
+++ b/tests/dibi/DibiConnection.substitutions.phpt
@@ -11,16 +11,46 @@ $conn = new DibiConnection($config);
 $conn->getSubstitutes()->blog = 'wp_';
 
 Assert::same(
-	reformat('UPDATE wp_items SET [text]=\'Hello World\''),
-	$conn->translate("UPDATE :blog:items SET [text]='Hello World'")
+	reformat('UPDATE wp_items SET [val]=1'),
+	$conn->translate('UPDATE :blog:items SET [val]=1')
 );
 
 Assert::same(
-	reformat('UPDATE \'wp_\' SET [text]=\'Hello World\''),
-	$conn->translate("UPDATE :blog: SET [text]='Hello World'")
+	reformat('UPDATE [wp_items] SET [val]=1'),
+	$conn->translate('UPDATE [:blog:items] SET [val]=1')
 );
 
 Assert::same(
-	reformat('UPDATE \':blg:\' SET [text]=\'Hello World\''),
-	$conn->translate("UPDATE :blg: SET [text]='Hello World'")
+	reformat("UPDATE 'wp_' SET [val]=1"),
+	$conn->translate('UPDATE :blog: SET [val]=1')
+);
+
+Assert::same(
+	reformat("UPDATE ':blg:' SET [val]=1"),
+	$conn->translate('UPDATE :blg: SET [val]=1')
+);
+
+Assert::same(
+	reformat("UPDATE table SET [text]=':blog:a'"),
+	$conn->translate("UPDATE table SET [text]=':blog:a'")
+);
+
+
+// create new substitution :: (empty)  ==>  my_
+$conn->getSubstitutes()->{''} = 'my_';
+
+Assert::same(
+	reformat('UPDATE my_table SET [val]=1'),
+	$conn->translate('UPDATE ::table SET [val]=1')
+);
+
+
+// create substitutions using fallback callback
+$conn->getSubstitutes()->setCallback(function ($expr) {
+	return '_' . $expr . '_';
+});
+
+Assert::same(
+	reformat('UPDATE _account_user SET [val]=1'),
+	$conn->translate('UPDATE :account:user SET [val]=1')
 );