diff --git a/re_test.go b/re_test.go
index d77265a..c9a1642 100644
--- a/re_test.go
+++ b/re_test.go
@@ -163,6 +163,16 @@ var reTests = []struct {
 	{"(?<=f)f+(?=f)", nil, "fffff", []Group{{1, 4}}},
 	{"(?<=f)f+(?=f)", nil, "fffffa", []Group{{1, 4}}},
 
+	// Some POSIX charclass tests
+	{"[[:lower:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{0, 26}}},
+	{"[[:upper:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{26, 52}}},
+	{"[[:alpha:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{0, 52}}},
+	{"[[:digit:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{52, 62}}},
+	{"[[:alnum:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{0, 62}}},
+	{"[[:punct:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{62, 70}}},
+	{"[[:ascii:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{0, 70}}},
+	{"[[:graph:]]+", nil, "abcdefghijklmnopqrstuvwyxzABCDEFGHIJKLMNOPRQSTUVWXYZ0123456789!@#$%^&*", []Group{{0, 70}}},
+
 	// Test cases from Python's RE test suite
 	{`[\1]`, nil, "\x01", []Group{{0, 1}}},