Running into problems with Clojure return types

28.clj

(ns com.koddsson.for-clojure
  (:use [clojure.test :only [is deftest run-tests]]))

(defn my-flatten
  ([x] (if (not (and (seq? x) (vector? x)))
           x                      ; If x is not a sequence nor a vector
           (map my-flatten x))))  ; else recursivly apply the flatten function

(deftest test28
  (is (= (my-flatten '((1 2) 3 [4 [5 6]])) '(1 2 3 4 5 6)))
  (is (= (my-flatten ["a" ["b"] "c"]) '("a" "b" "c")))
  (is (= (my-flatten '((((:a))))) '(:a))))

(run-tests)

test_results.clj

λ bubblegum 20 → λ git master* → lein exec -p 28.clj

Testing com.koddsson.for-clojure

FAIL in (test28) (28.clj:10)
expected: (= (my-flatten (quote ((1 2) 3 [4 [5 6]]))) (quote (1 2 3 4 5 6)))
  actual: (not (= ((1 2) 3 [4 [5 6]]) (1 2 3 4 5 6)))

FAIL in (test28) (28.clj:11)
expected: (= (my-flatten ["a" ["b"] "c"]) (quote ("a" "b" "c")))
  actual: (not (= ["a" ["b"] "c"] ("a" "b" "c")))

FAIL in (test28) (28.clj:12)
expected: (= (my-flatten (quote ((((:a)))))) (quote (:a)))
  actual: (not (= ((((:a)))) (:a)))

Ran 1 tests containing 3 assertions.
3 failures, 0 errors.

Try this:

(defn my-flatten
  [x]
  (if-not (or (seq? x) (vector? x))
    [x]
    (mapcat my-flatten x)))