+(ert-deftest test-seq-position ()
+ (with-test-sequences (seq '(2 4 6))
+ (should (null (seq-position seq 1)))
+ (should (= (seq-position seq 4) 1)))
+ (let ((seq '(a b c)))
+ (should (null (seq-position seq 'd #'eq)))
+ (should (= (seq-position seq 'a #'eq) 0))
+ (should (null (seq-position seq (make-symbol "a") #'eq)))))
+
+(ert-deftest test-seq-mapn ()
+ (should-error (seq-mapn #'identity))
+ (with-test-sequences (seq '(1 2 3 4 5 6 7))
+ (should (equal (append seq nil)
+ (seq-mapn #'identity seq)))
+ (should (equal (seq-mapn #'1+ seq)
+ (seq-map #'1+ seq)))
+
+ (with-test-sequences (seq-2 '(10 20 30 40 50))
+ (should (equal (seq-mapn #'+ seq seq-2)
+ '(11 22 33 44 55)))
+ (should (equal (seq-mapn #'+ seq seq-2 nil) nil)))))
+
+(ert-deftest test-seq-sort-by ()
+ (let ((seq ["x" "xx" "xxx"]))
+ (should (equal (seq-sort-by #'seq-length #'> seq)
+ ["xxx" "xx" "x"]))))
+