Subvec should not delegate -find, additional tests

Author: swannodette

src/main/cljs/cljs/core.cljs

@@ -5524,9 +5524,10 @@ reduces them without incurring seq initialization"
 
   IFind
   (-find [coll n]
-    (when (and (not (neg? n))
-               (< (+ start n) end))
-      (-find v (+ start n))))
+    (when-not (neg? n)
+      (let [idx (+ start n)]
+        (when (< idx end)
+          [n (-lookup v idx)]))))
 
   IVector
   (-assoc-n [coll n val]

src/test/cljs/cljs/collections_test.cljs

@@ -99,12 +99,17 @@
         (testing "rseq equality"
           (is (= (rseq sv1) '(1)))
           (is (nil? (rseq sv2)))))
-      (let [s (subvec [0 1 2 3] 0 2)]
+      (let [sv1 (subvec [0 1 2 3] 0 2)
+            sv2 (subvec [0 1 2 3] 1 3)]
         (testing "IFind"
-          (is (= (find s 0) [0 0]))
-          (is (= (find s 1) [1 1]))
-          (is (= (find s 2) nil))
-          (is (= (find s -1) nil))))
+          (is (= (find sv1 0) [0 0]))
+          (is (= (find sv1 1) [1 1]))
+          (is (= (find sv1 2) nil))
+          (is (= (find sv1 -1) nil))
+          (is (= (find sv2 0) [0 1]))
+          (is (= (find sv2 1) [1 2]))
+          (is (= (find sv2 2) nil))
+          (is (= (find sv2 -1) nil))))
       )
     ))