Test case for destructuring in clojure for database connectivity - clojure

Question

I started working on clojure a week back and i am not able to write a test case for the below code for destructuring of maps using default values:
(defn connect-db [{:keys [host port db-name username password]
:or {host "localhost"
port 12345
db-name "my-db"
username "db-user"
password "secret"}
:as cfg}]
(if (= " " host)
"Error: host name not available"
(try
(println "connecting to:" host "port:" port "db-name:" db-name
"username:" username "password:" password)
(catch Exception e(str "caught exception:" (.getMessage e))))))
The test case should be written using deftest.

Answer 1

I'm not sure if there is much to gain from testing destructuring, because it's a core part of the language and is built into fn, defn, let etc. Assume that it works and test only your own code. If you want to build confidence that it works the way you expect, play about with it in the REPL. There are plenty of examples here.
We can try out some defaults like this:
(let [{:keys [a b]
:or {a "a" b "b"}}
nil]
[a b])
=> ["a" "b"]

Answer 2

(deftest con-db
(is (= true (map? db)))
(is (= true (function? connectdb)))
(connectdb ["01" "20" "02" "03" "04"] {:host "localhost" :port 8888 :db-name "dbname" :username "name" :password "admin"})
(is(.equals "connecting: remote port: 8888 db-name: dbname username: name password: admin" outputdb))
(is(not(.equals "string" outputdb)))
(is(.equals "01-20" output))
(is(= 400 (- y x)))))