Add tests for empty

test/clojure/core_test/empty.cljc

@@ -0,0 +1,27 @@
+(ns clojure.core-test.empty
+  (:require clojure.core
+            [clojure.core-test.number-range :as r]
+            [clojure.test :as t :refer [deftest testing is are]]
+            [clojure.core-test.portability #?(:cljs :refer-macros :default :refer)  [when-var-exists]]))
+
+(when-var-exists clojure.core/empty
+  (deftest test-empty
+    (testing "common"
+      (are [expected x] (= expected (empty x))
+           []  [1 2]
+           {}  {:a :map}
+           '() '(1 2)
+           '() (range)
+           '() (range 10)
+           #{} #{1 2 3}
+           nil ""
+           nil \space
+           nil :a
+           nil 1
+           nil 0.0
+           nil nil
+           nil map
+           nil r/max-int
+           nil r/min-int
+           #?@(:cljs [nil (js/Date)]
+               :clj  [nil (new Object)])))))