Cache API responses and make sure we remember more than just one

Closes #21.
Squashed commit of the following:

commit 964b29cf127cf51de86543d040bcb6c674b36d7e
Author: Arne Schlüter <arne@schlueter.is>
Date:   Wed Aug 22 17:56:48 2018 +0200

    Pass content for current route nicely to views

commit b469a0a4b69457ddf3a679ac1acc82fbaffdc8fd
Author: Arne Schlüter <arne@schlueter.is>
Date:   Wed Aug 22 16:01:04 2018 +0200

    Add response cache in app-db

commit da9faf89138f42ee544efc64c2e46787091b3dc7
Author: Arne Schlüter <arne@schlueter.is>
Date:   Wed Aug 22 13:40:57 2018 +0200

    Move api helpers and tests to own namespace

test/cljs/airsonic_ui/api/events_test.cljs

@@ -0,0 +1,50 @@
+(ns airsonic-ui.api.events-test
+  (:require [cljs.test :refer-macros [deftest testing is]]
+            [airsonic-ui.api.events :as events]
+            [airsonic-ui.fixtures :as fixtures]))
+
+(enable-console-print!)
+
+(deftest api-failure-notifcations
+  (testing "Should show an error notification when airsonic responds with an error"
+    (let [fx (events/good-api-response {} [:api/good-response "ping" nil (:error fixtures/responses)])
+          ev (:dispatch fx)]
+      (is (= :notification/show (first ev)))
+      (is (= :error (second ev))))))
+
+(deftest cached-api-requests
+  (letfn [(cache [fx [endpoint params]]
+            (get-in fx [:db :api/responses [endpoint params]]))]
+    (testing "Should be cached"
+      (testing "when the response was successful"
+        (let [endpoint "getScanStatus"
+              successful (events/good-api-response {} [:api/good-response endpoint nil (:ok fixtures/responses)])
+              unsuccessful (events/good-api-response {} [:api/good-response endpoint nil (:error fixtures/responses)])]
+          (is (map? (cache successful [endpoint])))
+          (is (nil? (cache unsuccessful [endpoint])))))
+      (testing "in an unwrapped format"
+        (let [endpoint "getScanStatus"
+              fx (events/good-api-response {} [:api/good-response endpoint nil (:ok fixtures/responses)])]
+          (is (= #{:count :scanning} (set (keys (cache fx [endpoint]))))))))
+    (testing "When being issued"
+      (let [endpoint "getScanStatus"
+            fx (events/api-request {:db {:credentials (select-keys fixtures/credentials [:server])}}
+                                   [:api/request endpoint])]
+        (testing "should send an http request"
+          (is (contains? fx :http-xhrio)))
+        (testing "should indicate that a request is ongoing"
+          (is (true? (:api/is-loading? (cache fx [endpoint]))) "for non-cached responses")
+          (is (true? (-> (events/good-api-response fx [:api/good-response endpoint nil (:ok fixtures/responses)])
+                         (events/api-request [:api/request endpoint])
+                         (cache [endpoint])
+                         :api/is-loading?)) "for cached responses"))
+        (testing "should remove the indication that a request is ongoing when there is a response"
+          (is (not (:api/is-loading? (-> (events/good-api-response fx [:api/good-response endpoint nil (:ok fixtures/responses)])
+                                         (cache [endpoint])))) "for a good response")
+          (is (not (:api/is-loading? (-> (merge fx (events/good-api-response fx [:api/good-response endpoint nil (:error fixtures/responses)]))
+                                         (cache [endpoint])))) "when an error is returned")
+          (is (not (:api/is-loading? (-> (merge fx (events/failed-api-response fx [:api/failed-response endpoint]))
+                                         (cache [endpoint])))) "when communication with the server failed"))))
+    (testing "Should be able to avoid the cache"
+      ;; FIXME: Implement this
+      )))

test/cljs/airsonic_ui/api/helpers_test.cljs

@@ -0,0 +1,57 @@
+(ns airsonic-ui.api.helpers-test
+  (:require [cljs.test :refer [deftest testing is]]
+            [clojure.string :as str]
+            [airsonic-ui.fixtures :refer [responses]]
+            [airsonic-ui.api.helpers :as api]))
+
+(defn- url
+  "Construct a url with no params"
+  [server endpoint]
+  (api/url server endpoint {}))
+
+(def fixtures
+  {:default-url (url "http://localhost:8080" "ping")})
+
+(deftest general-url-construction
+  (testing "Handles missing slashes"
+    (is (true? (str/starts-with? (fixtures :default-url)  "http://localhost:8080/rest/ping")))
+    (is (true? (str/starts-with? (url "http://localhost:8080/" "ping") "http://localhost:8080/rest/ping"))))
+  (testing "Should set correct default parameters"
+    (is (string? (re-find #"f=json" (fixtures :default-url))))
+    (is (string? (re-find #"v=1\.15\.0" (fixtures :default-url))))))
+
+(deftest song-urls
+  (testing "Should construct the url based on a song's id"
+    (let [song {:id 1234}]
+      (is (true? (str/includes? (api/song-url "http://localhost" {} song) (str "id=" (:id song))))))))
+
+(deftest cover-urls
+  (let [album {:coverArt "cover-99999"}]
+    (testing "Should construct the url based on an item's cover-id"
+      (is (true? (str/includes? (api/cover-url "http://server.tld" {} album -1) (str "id=" (:coverArt album))))))
+    (testing "Should scale an image to a given size"
+      (is (true? (str/includes? (api/cover-url "http://server.tld" {} album 48) "size=48"))))))
+
+(deftest response-handling
+  (testing "Should unwrap responses"
+    (let [response (:ok responses)]
+      (is (= (get-in response [:subsonic-response :scanStatus])
+             (api/unwrap-response response)))))
+  (testing "Should detect errors"
+    (is (true? (api/is-error? (:error responses))))
+    (is (false? (api/is-error? (:ok responses)))))
+  (testing "Should throw an informative error when trying to unwrap an erroneous response"
+    (let [error-response (:error responses)]
+      (is (thrown? ExceptionInfo (api/unwrap-response error-response)))
+      (try
+        (api/unwrap-response error-response)
+        (catch ExceptionInfo e
+          (= (:error error-response) (ex-data e)))))))
+
+(deftest error-recognition
+  (testing "Should detect error responses"
+    (is (true? (api/is-error? (:error responses))))
+    (is (true? (api/is-error? (:auth-failure responses)))))
+  (testing "Should pass on good responses"
+    (is (false? (api/is-error? (:ok responses))))
+    (is (false? (api/is-error? (:auth-success responses))))))

test/cljs/airsonic_ui/api/subs_test.cljs

@@ -0,0 +1,29 @@
+(ns airsonic-ui.api.subs-test
+  (:require [cljs.test :refer-macros [deftest testing is]]
+            [airsonic-ui.api.subs :as sub]))
+
+(enable-console-print!)
+
+(deftest endpoint-keywordification
+  (testing "Should strip prefixes"
+    (is (= :artist-info (sub/endpoint->kw "getArtistInfo")))
+    (is (= :jukebox-control (sub/endpoint->kw "jukeboxControl"))))
+  (testing "Should strip trailing numbers"
+    (is (= :album-list (sub/endpoint->kw "getAlbumList2")))
+    (is (= :search (sub/endpoint->kw "search3")))))
+
+(deftest responses-for-route
+  (testing "Should return all cached responses for a route"
+    (let [route-events [[:api/request "getAlbumList2" {:type "recent", :size 18}]
+                        [:event/should-be-ignored]
+                        [:api/request "getArtistInfo" {:id "128"}]]
+          db {:api/responses {["getAlbumList2" {:type "recent" :size 18}]
+                              {:album [{:genre "foo", :artistId "12345"}
+                                       {:genre "electronic", :artistId "9999"}]}
+
+                              ["getArtistInfo" {:id "128"}]
+                              {:biography "Interesting bio"
+                               :largeImageUrl "https://lastfm-img2.akamaized.net/i/u/300x300/fb416b59cd694587aca0b2dec8f41198.png"}}}]
+      (is (= {:album-list (get-in db [:api/responses ["getAlbumList2" {:type "recent" :size 18}]])
+              :artist-info (get-in db [:api/responses ["getArtistInfo" {:id "128"}]])}
+             (sub/route-data db [:api/route-data route-events]))))))