Fix string search.

utils/list_test.go

@@ -7,10 +7,12 @@ import (
 type ListSuite struct {
 }
 
+var _ = Suite(&ListSuite{})
+
 func (s *ListSuite) TestStringsIsSubset(c *C) {
 	err := StringsIsSubset([]string{"a", "b"}, []string{"a", "b", "c"}, "[%s]")
 	c.Assert(err, IsNil)
 
 	err = StringsIsSubset([]string{"b", "a"}, []string{"b", "c"}, "[%s]")
-	c.Assert(err, ErrorMatches, "[a]")
+	c.Assert(err, ErrorMatches, "\\[a\\]")
 }