test merge

Author: daveliepmann

test/clojure/core_test/merge.cljc

@@ -0,0 +1,79 @@
+(ns clojure.core-test.merge
+  (:require [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/merge
+  (deftest test-merge
+    (testing "`merge`"
+      (testing "`nil` and empty map behavior"
+        (is (nil? (merge)))
+        (is (nil? (merge nil)))
+        (is (nil? (merge nil nil)))
+        (is (nil? (merge nil nil nil)))
+
+        (is (= {} (merge {})))
+        (is (= {} (merge {} nil)))
+        (is (= {} (merge nil {})))
+        (is (= {} (merge nil {} nil)))
+
+        (is (= {[2 3] :foo} (merge {[2 3] :foo} nil {})))
+        (is (= {1 11} (merge {1 11} {} nil))))
+
+      (testing "lattermost mapping wins"
+        (is (= {:a "aaaaa"} (merge {:a "a"} {:a "aaaaa"})))
+        (is (= {:a "a" :b "b"} (merge {:a "aaaa"} {:a "a" :b "b"})))
+        (is (= {:a "a" :b "b"} (merge {:a "aaaa"}
+                                      {:a "a" :b "bbbb"}
+                                      {:a "a" :b "b"})))
+        (is (= {:a nil :b "b" :c "c"} (merge {:a "aaaa"}
+                                             {:a "a" :b "bbbb" :c "c"}
+                                             {:a nil :b "b"})))
+        (is (= {:x 1 :y 10 :z 100} (merge {:x 1 :y 5555}
+                                          {:y 10 :z 100}))))
+
+      (testing "map entries are accepted in position 2+, per `conj`"
+        (is (= {:a "a", :b "b"} (merge {:a nil}
+                                       (first {:a "a"})
+                                       {:b "b"}))))
+
+      (testing "vectors in position 2+ are treated as map-entries, per `conj`"
+        (is (thrown? #?(:cljs :default, :clj java.lang.IllegalArgumentException, :clr Exception)
+                     (merge {} [])))
+        (is (thrown? #?(:cljs :default, :clj java.lang.IllegalArgumentException, :clr Exception)
+                     (merge {} [:foo])))
+        (is (= {:foo "foo"} (merge {} [:foo "foo"])))
+        (is (= {"x" 1} (merge {} ["x" 1])))
+        (is (= {'x 10, 'y 10} (merge {'x 10} ['y 10])))
+        (testing "In CLJS (unlike other dialects) vectors with >2 arguments are treated as map-entries (where the latter values are ignored)"
+          #?(:cljs (is (= {:foo :bar} (merge {} [:foo :bar :baz]))),
+             :clj (is (thrown? java.lang.IllegalArgumentException (merge {} [:foo :bar :baz]))),
+             :clr (is (thrown? Exception (merge {} [:foo :bar :baz])))))
+
+        (is (= {:foo "foo", :bar "bar"} (merge {} [:foo "foo"] [:bar "bar"])))
+        (is (= {'x 10, 'y 10, 'z 10} (merge {'x 10} ['y 10] ['z 10])))
+        (testing "In CLJS (unlike other dialects) vectors with >2 arguments are treated as map-entries (where the latter values are ignored)"
+          #?(:cljs (is (= {:foo :bar} (merge {} [:foo :bar :baz :bar]))),
+             :clj (is (thrown? java.lang.IllegalArgumentException (merge {} [:foo :bar :baz :bar]))),
+             :clr (is (thrown? Exception (merge {} [:foo :bar :baz :bar]))))))
+
+      (testing "atomic values in position 2+ throw"
+        (is (thrown? #?(:cljs :default, :clj Exception, :clr Exception)
+                     (merge {} 1)))
+        (is (thrown? #?(:cljs :default, :clj Exception, :clr Exception)
+                     (merge {} 1 2)))
+        (is (thrown? #?(:cljs :default, :clj Exception, :clr Exception)
+                     (merge {} :foo)))
+        (is (thrown? #?(:cljs :default, :clj Exception, :clr Exception)
+                     (merge {} "str"))))
+
+      ;; Behavior for non-maps is undefined and intentionally not tested.
+      (comment
+        (merge '(1 2 3) 1)
+        (merge [1 2] 3 4 5)
+        (merge [] nil {} 1 {:a "c"})
+        (merge (first {:a "a"}) {:b "b"} {:c "c"})
+        (merge :foo)
+        (merge :foo :bar)
+        (merge {} (range))
+        (merge {} '(1 2))
+        (merge {} 1 2)))))