Merge pull request #1410 from eval/fix-1310-clojure

#1310 clojure: tests and example conform instruction

assignments/clojure/rna-transcription/example.clj

@@ -1,13 +1,17 @@
 (ns dna)
 
-(def adenosine \A)
-(def cytadine  \C)
-(def guanosine \G)
-(def thymidine \T)
-(def uracil    \U)
+(def dna->rna {
+      \C \G
+      \G \C
+      \A \U
+      \T \A})
+
+(defn validate-strand [strand]
+  (let [valid-dna (set (keys dna->rna))]
+    (every? valid-dna strand)))
 
 (defn to-rna
   [strand]
-  {:pre [(every? #{adenosine cytadine guanosine thymidine}
-                 (set strand))]}
-  (clojure.string/replace strand thymidine uracil))
+  {:pre [(validate-strand strand)]}
+  (apply str
+    (map dna->rna (seq strand))))

assignments/clojure/rna-transcription/rna_transcription_test.clj

@@ -2,19 +2,19 @@
 (load-file "dna.clj")
 
 (deftest transcribes-cytidine-unchanged
-  (is (= "C" (dna/to-rna "C"))))
+  (is (= "G" (dna/to-rna "C"))))
 
 (deftest transcribes-guanosine-unchanged
-  (is (= "G" (dna/to-rna "G"))))
+  (is (= "C" (dna/to-rna "G"))))
 
 (deftest transcribes-adenosine-unchanged
-  (is (= "A" (dna/to-rna "A"))))
+  (is (= "U" (dna/to-rna "A"))))
 
 (deftest it-transcribes-thymidine-to-uracil
-  (is (= "U" (dna/to-rna "T"))))
+  (is (= "A" (dna/to-rna "T"))))
 
 (deftest it-transcribes-all-occurrences-of-thymidine-to-uracil
-  (is (= "ACGUGGUCUUAA" (dna/to-rna "ACGTGGTCTTAA"))))
+  (is (= "UGCACCAGAAUU" (dna/to-rna "ACGTGGTCTTAA"))))
 
 (deftest it-validates-dna-strands
   (is (thrown? AssertionError (dna/to-rna "XCGFGGTDTTAA"))))