diff --git a/test/honeysql/format_test.clj b/test/honeysql/format_test.clj
index e0f8bca..26f90bc 100644
--- a/test/honeysql/format_test.clj
+++ b/test/honeysql/format_test.clj
@@ -53,3 +53,13 @@
                   :columns [:baz]
                   :values [[#sql/array ["one" "two" "three"]]]})
          ["INSERT INTO foo (baz) VALUES (ARRAY[?, ?, ?])" "one" "two" "three"])))
+
+(deftest union-test
+  (is (= (format {:union [{:select [:foo] :from [:bar1]}
+                          {:select [:foo] :from [:bar2]}]})
+         ["(SELECT foo FROM bar1) UNION (SELECT foo FROM bar2)"])))
+
+(deftest union-all-test
+  (is (= (format {:union-all [{:select [:foo] :from [:bar1]}
+                              {:select [:foo] :from [:bar2]}]})
+         ["(SELECT foo FROM bar1) UNION ALL (SELECT foo FROM bar2)"])))