diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
new file mode 100644
index 0000000..ff8436c
--- /dev/null
+++ b/.github/workflows/test.yaml
@@ -0,0 +1,18 @@
+name: Test
+
+on:
+  push:
+
+jobs:
+  run-tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+      - name: Setup deno
+        uses: denoland/setup-deno@v1
+        with:
+          deno-version: v1.x
+      - name: Run checks
+        run: deno task check
+      - name: Run test
+        run: deno task test
diff --git a/components/Search.tsx b/components/Search.tsx
index e264d49..da0863a 100644
--- a/components/Search.tsx
+++ b/components/Search.tsx
@@ -1,4 +1,4 @@
-export default function Search(props: { defaultValue: string }) {
+export default function Search(props: { defaultValue: string | null }) {
   return (
     <form className="flex flex-col w-full lg:w-2/3 mx-auto my-4">
       <label className="sr-only" htmlFor="query">Program</label>
@@ -8,7 +8,7 @@ export default function Search(props: { defaultValue: string }) {
         className="border-2 rounded-md px-2"
         name="query"
         id="query"
-        defaultValue={props.defaultValue}
+        defaultValue={props.defaultValue ?? ""}
       />
       <button type="submit" className="my-2 bg-gray-100 border-2 border-gray-400 rounded-md">
         Søk
diff --git a/deno.json b/deno.json
index f1f68ed..4b89361 100644
--- a/deno.json
+++ b/deno.json
@@ -6,7 +6,8 @@
   "tasks": {
     "start": "deno run -A --watch=static/,routes/ dev.ts",
     "check": "deno fmt --check && deno lint && deno check **/*.ts && deno check **/*.tsx",
-    "types:nrk": "deno run -A generate-types.ts && deno fmt ./lib"
+    "types:nrk": "deno run -A generate-types.ts && deno fmt ./lib",
+    "test": "deno test -A"
   },
   "unstable": [
     "kv"
@@ -20,9 +21,8 @@
     "@preact/signals-core": "https://esm.sh/*@preact/signals-core@1.5.1",
     "$gfm": "https://deno.land/x/gfm@0.6.0/mod.ts",
     "openapi-typescript": "npm:openapi-typescript@6.7.5",
-    "datetime": "https://deno.land/std@0.221.0/datetime/mod.ts",
-    "asserts": "https://deno.land/std@0.221.0/assert/mod.ts",
-    "serialize-xml": "https://raw.githubusercontent.com/olaven/serialize-xml/v0.4.0/mod.ts"
+    "serialize-xml": "https://raw.githubusercontent.com/olaven/serialize-xml/v0.4.0/mod.ts",
+    "$std/": "https://deno.land/std@0.221.0/"
   },
   "compilerOptions": {
     "jsx": "react-jsx",
diff --git a/generate-types.ts b/generate-types.ts
index c481263..693f601 100644
--- a/generate-types.ts
+++ b/generate-types.ts
@@ -2,15 +2,15 @@ import openapiTS from "openapi-typescript";
 
 const nrkTypes: { filename: string; url: URL }[] = [
   {
-    filename: "./lib/nrk-search.ts",
+    filename: "./lib/nrk/nrk-search.ts",
     url: new URL("https://psapi.nrk.no/documentation/openapi/search-radio/v1/openapi.yml"),
   },
   {
-    filename: "./lib/nrk-catalog.ts",
+    filename: "./lib/nrk/nrk-catalog.ts",
     url: new URL("https://psapi.nrk.no/documentation/openapi/programsider-radio/openapi.yml"),
   },
   {
-    filename: "./lib/nrk-playback.ts",
+    filename: "./lib/nrk/nrk-playback.ts",
     url: new URL("https://psapi.nrk.no/documentation/openapi/playback/2.0/openapi.json"),
   },
 ] as const;
diff --git a/lib/caching.test.ts b/lib/caching.test.ts
new file mode 100644
index 0000000..a8c5239
--- /dev/null
+++ b/lib/caching.test.ts
@@ -0,0 +1,51 @@
+import { assertEquals } from "$std/assert/mod.ts";
+import { forTestingOnly } from "./caching.ts";
+import { testUtils } from "./test-utils.ts";
+
+Deno.test("Verify getTimeSinceLastFetch for correct difference", () => {
+  const earlyDate = new Date("2024-04-07T20:24:32Z");
+  const date = new Date("2024-04-07T23:24:32Z");
+  const timeSinceLastFetch = forTestingOnly.getTimeSinceLastFetch(date, earlyDate);
+
+  assertEquals(timeSinceLastFetch, 3);
+});
+
+Deno.test("Verify getTimeSinceLastFetch for bad date", () => {
+  const earlyDate = new Date("2024-04-07T20:24:32Z");
+  const date = new Date("bad date");
+  const timeSinceLastFetch = forTestingOnly.getTimeSinceLastFetch(date, earlyDate);
+
+  assertEquals(timeSinceLastFetch, NaN);
+});
+
+Deno.test("Verify getTimeSinceLastFetch for bad dates (plural)", () => {
+  const earlyDate = new Date("badest date");
+  const date = new Date("bad date");
+  const timeSinceLastFetch = forTestingOnly.getTimeSinceLastFetch(date, earlyDate);
+
+  assertEquals(timeSinceLastFetch, NaN);
+});
+
+Deno.test("Verify seriesFromStorage is old", () => {
+  const earlyDate = new Date("2024-04-07T21:24:32Z");
+  const date = new Date("2024-04-07T23:24:32Z");
+  const timeSinceLastFetch = forTestingOnly.getTimeSinceLastFetch(date, earlyDate);
+
+  const series = testUtils.generateSeries({ lastFetchedAt: date });
+  const syncInterval = 2;
+  const isNew = forTestingOnly.isSeriesFromStorageNew(series, syncInterval, timeSinceLastFetch);
+
+  assertEquals(isNew, true);
+});
+
+Deno.test("Verify seriesFromStorage is new", () => {
+  const earlyDate = new Date("2024-04-07T20:24:32Z");
+  const date = new Date("2024-04-07T23:24:32Z");
+  const timeSinceLastFetch = forTestingOnly.getTimeSinceLastFetch(date, earlyDate);
+
+  const series = testUtils.generateSeries({ lastFetchedAt: date });
+  const syncInterval = 2;
+  const isNew = forTestingOnly.isSeriesFromStorageNew(series, syncInterval, timeSinceLastFetch);
+
+  assertEquals(isNew, false);
+});
diff --git a/lib/caching.ts b/lib/caching.ts
index 72eec24..3ee20e1 100644
--- a/lib/caching.ts
+++ b/lib/caching.ts
@@ -1,21 +1,33 @@
 import { nrkRadio } from "./nrk/nrk.ts";
 import { Series, storage } from "./storage.ts";
-import * as datetime from "datetime";
+import * as datetime from "$std/datetime/mod.ts";
+import { Episode } from "./storage.ts";
 
 const SYNC_INTERVAL_HOURS = 1;
 
-async function initialFetch(options: { id: string }) {
+async function initialFetch(options: { id: string }): Promise<Series | null> {
   const series = await nrkRadio.getSeries(options.id);
+  if (!series) {
+    return null;
+  }
   const stored = storage.write(series);
   if (!stored) {
-    throw new Error(`Failed to store series ${options.id}`);
+    console.error(`Failed to store series ${options.id}`);
+    return null;
   }
 
   return series;
 }
 
-async function updateFetch(existingSeries: Series) {
+type UpdatedSeries = {
+  lastFetch: Date;
+  episodes: Episode[];
+} & Series;
+async function updateFetch(existingSeries: Series): Promise<UpdatedSeries | Series | null> {
   const series = await nrkRadio.getSeries(existingSeries.id);
+  if (!series) {
+    return null;
+  }
   const newEpisodes = series.episodes.filter((episode) => {
     return !existingSeries.episodes.find((serieEpisode) => serieEpisode.id === episode.id);
   });
@@ -24,27 +36,46 @@ async function updateFetch(existingSeries: Series) {
     return existingSeries;
   }
 
+  /**
+   * Since we don't control the API,
+   * we should not make assumptions about the order,
+   * but rather sort the episode to what we want.
+   */
+  const episodesSortedDescending = [...newEpisodes, ...existingSeries.episodes]
+    .sort((a, b) => a.date.getTime() > b.date.getTime() ? -1 : 1);
+
   const updated = {
     ...existingSeries,
     lastFetch: new Date(),
-    /**
-     * Since we don't control the API,
-     * we should not make assumptions about the order,
-     * but rather sort the episode to what we want.
-     */
-    episodes: [...newEpisodes, ...existingSeries.episodes]
-      .sort((a, b) => a.date.getTime() > b.date.getTime() ? -1 : 1),
+    episodes: episodesSortedDescending,
   };
 
   const updateSuccessful = await storage.write(updated);
   if (!updateSuccessful) {
-    throw new Error(`Failed to update series ${existingSeries.id}`);
+    console.log(`Failed to update series ${existingSeries.id}`);
+    return null;
   }
 
   return updated;
 }
 
-async function getSeries(options: { id: string }): Promise<Series> {
+function getTimeSinceLastFetch(inputDate: Date, againstDate = new Date()): number | null {
+  return datetime.difference(inputDate, againstDate, { units: ["hours"] }).hours ?? null;
+}
+
+function isSeriesFromStorageNew(
+  seriesFromStorage: Series,
+  syncInterval = SYNC_INTERVAL_HOURS,
+  timeSinceLastFetch = getTimeSinceLastFetch(seriesFromStorage.lastFetchedAt),
+) {
+  return !Number.isNaN(timeSinceLastFetch) &&
+    seriesFromStorage !== null &&
+    timeSinceLastFetch !== null &&
+    timeSinceLastFetch !== undefined &&
+    timeSinceLastFetch <= syncInterval;
+}
+
+async function getSeries(options: { id: string }): Promise<Series | null> {
   const seriesFromStorage = await storage.read(options);
 
   /**
@@ -56,16 +87,8 @@ async function getSeries(options: { id: string }): Promise<Series> {
     return await initialFetch(options);
   }
 
-  const timeSinceLastFetch =
-    datetime.difference(seriesFromStorage.lastFetchedAt, new Date(), { units: ["hours"] }).hours;
-
   // we have the feed in storage and it's not too old
-  if (
-    seriesFromStorage !== null &&
-    timeSinceLastFetch !== null &&
-    timeSinceLastFetch !== undefined &&
-    timeSinceLastFetch <= SYNC_INTERVAL_HOURS
-  ) {
+  if (isSeriesFromStorageNew(seriesFromStorage)) {
     return seriesFromStorage;
   }
 
@@ -80,3 +103,8 @@ async function getSeries(options: { id: string }): Promise<Series> {
 export const caching = {
   getSeries,
 };
+
+export const forTestingOnly = {
+  getTimeSinceLastFetch,
+  isSeriesFromStorageNew,
+};
diff --git a/lib/nrk/nrk.test.ts b/lib/nrk/nrk.test.ts
new file mode 100644
index 0000000..083075c
--- /dev/null
+++ b/lib/nrk/nrk.test.ts
@@ -0,0 +1,52 @@
+import { assertEquals, assertExists, assertGreaterOrEqual } from "$std/assert/mod.ts";
+import { nrkRadio } from "./nrk.ts";
+import { forTestingOnly } from "./nrk.ts";
+
+Deno.test("Verify search query `trygd` returns one result: 'Trygdekontoret'", async () => {
+  const result = await nrkRadio.search("trygd");
+  assertExists(result);
+  assertEquals(result.length, 1);
+  assertEquals(result[0].seriesId, "trygdekontoret");
+});
+
+Deno.test("Verify empty search query yields `null`", async () => {
+  const result = await nrkRadio.search("");
+  assertEquals(result, null);
+});
+
+Deno.test("Verify getting series data for 'trygdekontoret' works", async () => {
+  const result = await forTestingOnly.getSeriesData("trygdekontoret");
+  assertExists(result);
+  assertGreaterOrEqual(result.episodes.length, 1);
+});
+
+Deno.test("Verify getting series data for 'trygdekontoret' works", async () => {
+  const seriesData = await forTestingOnly.getSeriesData("trygdekontoret");
+  assertExists(seriesData);
+  const result = nrkRadio.parseSeries(seriesData);
+  assertExists(result);
+  assertGreaterOrEqual(result.episodes.length, 1);
+  assertEquals(result.title, "Trygdekontoret");
+});
+
+Deno.test("Verify getting series for 'trygdekontoret' works", async () => {
+  const result = await nrkRadio.getSeries("trygdekontoret");
+  assertExists(result);
+  assertGreaterOrEqual(result.episodes.length, 1);
+});
+
+Deno.test("Verify getting series data for 'trygd' does not works", async () => {
+  const result = await nrkRadio.getSeries("trygd");
+  assertEquals(result, null);
+});
+
+Deno.test("Verify getting episodeId 'l_0bc5e55a-46b5-48a5-85e5-5a46b5d8a562' for 'trygdekontoret' works", async () => {
+  const result = await nrkRadio.getEpisode("trygdekontoret", "l_0bc5e55a-46b5-48a5-85e5-5a46b5d8a562");
+  assertExists(result);
+  assertEquals(result.duration.seconds, 4152);
+});
+
+Deno.test("Verify getting episodeId 'null' for 'trygdekontoret' yields `null`", async () => {
+  const result = await nrkRadio.getEpisode("trygdekontoret", "null");
+  assertEquals(result, null);
+});
diff --git a/lib/nrk/nrk.ts b/lib/nrk/nrk.ts
index e18af3d..785f959 100644
--- a/lib/nrk/nrk.ts
+++ b/lib/nrk/nrk.ts
@@ -1,4 +1,4 @@
-import { get, OK } from "https://deno.land/x/kall@v0.1.0/mod.ts";
+import { get, STATUS_CODE } from "https://deno.land/x/kall@v2.0.0/mod.ts";
 import { components as searchComponents } from "./nrk-search.ts";
 import { components as catalogComponents } from "./nrk-catalog.ts";
 import { external as playbackComponents } from "./nrk-playback.ts";
@@ -8,6 +8,8 @@ type ArrayElement<A> = A extends readonly (infer T)[] ? T : never;
 type PodcastEpisodes = catalogComponents["schemas"]["EpisodesHalResource"];
 type Podcast = catalogComponents["schemas"]["SeriesHalResource"];
 type PodcastEpisodesSingle = catalogComponents["schemas"]["EpisodeHalResource"];
+type RadioSeriesEpisode = catalogComponents["schemas"]["EpisodesHalResource"];
+type RadioSeries = catalogComponents["schemas"]["SeriesHalResource"];
 
 export type NrkSerie = catalogComponents["schemas"]["SeriesViewModel"];
 export type NrkOriginalEpisode = PodcastEpisodesSingle & { url: string };
@@ -16,21 +18,19 @@ export type NrkSearchResultList = searchComponents["schemas"]["seriesResult"]["r
 export type SearchResult = ArrayElement<NrkSearchResultList> & {
   description?: string;
 };
+export type SeriesData = { episodes: NrkOriginalEpisode[] } & (RadioSeries["series"] | Podcast["series"]);
 
-type Manifest = playbackComponents["schemas/playback-channel.json"]["components"]["schemas"]["PlayableManifest"];
-type NrkSerieData = Awaited<ReturnType<typeof nrkRadio.getSeries>>;
-
-function parseSeries(nrkSeries: NrkSerieData): Series {
-  const imageUrl = nrkSeries.squareImage?.at(-1)?.url ?? "";
+function parseSeries(nrkSeriesData: SeriesData): Series {
+  const imageUrl = nrkSeriesData.squareImage?.at(-1)?.url ?? "";
 
   return {
-    id: nrkSeries.id,
-    title: nrkSeries.titles.title,
-    subtitle: nrkSeries.titles.subtitle ?? null,
-    link: `https://radio.nrk.no/podkast/${nrkSeries.id}`,
+    id: nrkSeriesData.id,
+    title: nrkSeriesData.titles.title,
+    subtitle: nrkSeriesData.titles.subtitle ?? null,
+    link: `https://radio.nrk.no/podkast/${nrkSeriesData.id}`,
     imageUrl: imageUrl,
     lastFetchedAt: new Date(),
-    episodes: nrkSeries.episodes.map((episode) => {
+    episodes: nrkSeriesData.episodes.map((episode) => {
       return {
         id: episode.id,
         title: episode.titles.title,
@@ -46,89 +46,121 @@ function parseSeries(nrkSeries: NrkSerieData): Series {
 
 const nrkAPI = `https://psapi.nrk.no`;
 
-async function withDownloadLink(
+async function search(query: string): Promise<NrkSearchResultList | null> {
+  if (query === "") {
+    console.error("Empty search query.");
+    return null;
+  }
+  const { status, body } = await get<
+    searchComponents["schemas"]["searchresult"]
+  >(`${nrkAPI}/radio/search/search?q=${query}`);
+  if (status === STATUS_CODE.OK && body) {
+    return body.results.series?.results;
+  }
+
+  console.error(`Something went wrong with ${query} - got status ${status}`);
+  return null;
+}
+
+async function getSeriesData(seriesId: string): Promise<SeriesData | null> {
+  let [
+    { status: episodeStatus, body: episodeResponse },
+    { status: seriesStatus, body: serieResponse },
+  ] = await Promise.all([
+    get<PodcastEpisodes>(
+      `${nrkAPI}/radio/catalog/podcast/${seriesId}/episodes`,
+    ),
+    get<Podcast>(
+      `${nrkAPI}/radio/catalog/podcast/${seriesId}`,
+    ),
+  ]);
+
+  if (episodeStatus !== STATUS_CODE.OK || seriesStatus !== STATUS_CODE.OK) {
+    [
+      { status: episodeStatus, body: episodeResponse },
+      { status: seriesStatus, body: serieResponse },
+    ] = await Promise.all([
+      get<RadioSeriesEpisode>(
+        `https://psapi.nrk.no/radio/catalog/series/${seriesId}/episodes`,
+      ),
+      get<RadioSeries>(
+        `https://psapi.nrk.no/radio/catalog/series/${seriesId}`,
+      ),
+    ]);
+  }
+
+  if (
+    episodeStatus === STATUS_CODE.OK && seriesStatus === STATUS_CODE.OK &&
+    serieResponse?.series && episodeResponse?._embedded.episodes?.length
+  ) {
+    const episodes = await Promise.all(
+      episodeResponse._embedded.episodes.map((episode) => getEpisodeWithDownloadLink(episode, serieResponse.type)),
+    );
+    const seriesData = {
+      ...serieResponse.series,
+      episodes,
+    };
+    return seriesData;
+  }
+  console.error(
+    `Error getting episodes for ${seriesId}: EpisodeStatus: ${episodeStatus}. SerieStatus: ${seriesStatus}`,
+  );
+  return null;
+}
+
+async function getSeries(seriesId: string): Promise<Series | null> {
+  const seriesData = await getSeriesData(seriesId);
+  if (!seriesData) {
+    return null;
+  }
+  const parsedSeries = parseSeries(seriesData);
+  return parsedSeries;
+}
+
+async function getEpisode(seriesId: string, episodeId: string): Promise<NrkPodcastEpisode | null> {
+  const url = `${nrkAPI}/radio/catalog/podcast/${seriesId}/episodes/${episodeId}`;
+  const { status, body: episode } = await get<NrkPodcastEpisode>(url);
+  if (status === STATUS_CODE.OK && episode) {
+    return episode;
+  }
+  console.error(`Error getting episode ${episodeId}. Status: ${status}. Series: ${seriesId}`);
+  return null;
+}
+
+type Manifest = playbackComponents["schemas/playback-channel.json"]["components"]["schemas"]["PlayableManifest"];
+
+async function getEpisodeWithDownloadLink(
   episode: PodcastEpisodesSingle,
   type: catalogComponents["schemas"]["Type"],
 ): Promise<NrkOriginalEpisode> {
   // getting stream link
-  let [playbackStatus, playbackResponse] = await get<Manifest>(
+  let { status: playbackStatus, body: playbackResponse } = await get<Manifest>(
     `${nrkAPI}/playback/manifest/podcast/${episode.episodeId}`,
   );
 
   if (type === "series") {
-    [playbackStatus, playbackResponse] = await get<Manifest>(
+    const { status, body } = await get<Manifest>(
       `${nrkAPI}/playback/manifest/program/${episode.episodeId}`,
     );
+    playbackStatus = status;
+    playbackResponse = body;
   }
 
-  if (playbackStatus === OK && playbackResponse) {
-    return { ...episode, url: playbackResponse.playable.assets[0].url };
-  } else {
-    throw `Error getting downloadLink for ${episode.episodeId}, serie: ${episode.originalTitle}. Status: ${playbackStatus}`;
+  if (playbackStatus !== STATUS_CODE.OK && !playbackResponse) {
+    throw new Error(
+      `Error getting downloadLink for ${episode.episodeId}, serie: ${episode.originalTitle}. Status: ${playbackStatus}`,
+    );
   }
+  return { ...episode, url: playbackResponse.playable.assets[0].url };
 }
 
 export const nrkRadio = {
-  search: async (query: string): Promise<NrkSearchResultList> => {
-    const [status, response] = await get<
-      searchComponents["schemas"]["searchresult"]
-    >(`${nrkAPI}/radio/search/search?q=${query}`);
-    if (status === OK && response) {
-      return response.results.series?.results;
-    }
-    throw `Something went wrong with ${query} - got status ${status}`;
-  },
-  getSeries: async (seriesId: string) => {
-    let [
-      [episodeStatus, episodeResponse],
-      [seriesStatus, serieResponse],
-    ] = await Promise.all([
-      get<PodcastEpisodes>(
-        `${nrkAPI}/radio/catalog/podcast/${seriesId}/episodes`,
-      ),
-      get<Podcast>(
-        `${nrkAPI}/radio/catalog/podcast/${seriesId}`,
-      ),
-    ]);
-
-    if (episodeStatus !== OK || seriesStatus !== OK) {
-      [
-        [episodeStatus, episodeResponse],
-        [seriesStatus, serieResponse],
-      ] = await Promise.all([
-        get<catalogComponents["schemas"]["EpisodesHalResource"]>(
-          `https://psapi.nrk.no/radio/catalog/series/${seriesId}/episodes`,
-        ),
-        get<catalogComponents["schemas"]["SeriesHalResource"]>(
-          `https://psapi.nrk.no/radio/catalog/series/${seriesId}`,
-        ),
-      ]);
-    }
-
-    if (
-      episodeStatus === OK && seriesStatus === OK &&
-      serieResponse?.series && episodeResponse?._embedded.episodes?.length
-    ) {
-      const episodes = await Promise.all(
-        episodeResponse._embedded.episodes.map((episode) => withDownloadLink(episode, serieResponse.type)),
-      );
-
-      const serieData = {
-        ...serieResponse.series,
-        episodes,
-      };
-
-      const parsedSeries = parseSeries(serieData);
-      return parsedSeries;
-    }
-    throw `Error getting episodes for ${seriesId}: EpisodeStatus: ${episodeStatus}. SerieStatus: ${seriesStatus}`;
-  },
-  getEpisode: async (seriesId: string, episodeId: string): Promise<NrkPodcastEpisode | null> => {
-    const url = `${nrkAPI}/radio/catalog/podcast/${seriesId}/episodes/${episodeId}`;
-    const [status, episode] = await get<NrkPodcastEpisode>(url);
-    if (status === OK && episode) {
-      return episode;
-    }
-    throw `Error getting episode ${episodeId}. Status: ${status}. Series: ${seriesId}`;
-  },
+  search,
+  getSeries,
+  getEpisode,
+  parseSeries,
+};
+
+export const forTestingOnly = {
+  getSeriesData,
 };
diff --git a/lib/rss.test.ts b/lib/rss.test.ts
index e399023..f3d0532 100644
--- a/lib/rss.test.ts
+++ b/lib/rss.test.ts
@@ -1,6 +1,14 @@
-import { assertEquals, assertExists } from "asserts";
+import { assertEquals, assertExists } from "$std/assert/mod.ts";
 import { testUtils } from "./test-utils.ts";
 import { rss } from "./rss.ts";
+import { forTestingOnly } from "./rss.ts";
+
+// NOTE: Could probably be expanded upon.
+Deno.test("generate tag for episode", () => {
+  const episode = testUtils.generateEpisode();
+  const tag = forTestingOnly.assembleEpisode(episode, "someId");
+  assertExists(tag);
+});
 
 Deno.test("generated rss contains the series title", () => {
   const series = testUtils.generateSeries();
diff --git a/lib/rss.ts b/lib/rss.ts
index 7e2a025..e02694e 100644
--- a/lib/rss.ts
+++ b/lib/rss.ts
@@ -1,8 +1,8 @@
-import { declaration, serialize, tag } from "serialize-xml";
-import { getHostName } from "../utils.ts";
+import { declaration, serialize, Tag, tag } from "serialize-xml";
+import { getHostName } from "./utils.ts";
 import { Episode, Series } from "./storage.ts";
 
-function assembleFeed(series: Series) {
+function assembleFeed(series: Series): string {
   // Originally adapted from https://raw.githubusercontent.com/olaven/paperpod/1cde9abd3174b26e126aa74fc5a3b63fd078c0fd/packages/converter/src/rss.ts
   return serialize(
     declaration([
@@ -44,7 +44,7 @@ function assembleFeed(series: Series) {
               ]),
             ]
             : []),
-          ...series.episodes.map((episode) => assembleEpisode({ series, episode })),
+          ...series.episodes.map((episode) => assembleEpisode(episode, series.id)),
         ]),
       ],
       [
@@ -57,9 +57,7 @@ function assembleFeed(series: Series) {
   );
 }
 
-function assembleEpisode(options: { series: Series; episode: Episode }) {
-  const { series, episode } = options;
-
+function assembleEpisode(episode: Episode, seriesId: Series["id"]): Tag {
   const description = episode.subtitle || "";
 
   return tag("item", [
@@ -73,7 +71,7 @@ function assembleEpisode(options: { series: Series; episode: Episode }) {
     tag("podcast:chapters", "", [
       [
         "url",
-        `${getHostName()}/api/feeds/${series.id}/${episode.id}/chapters`,
+        `${getHostName()}/api/feeds/${seriesId}/${episode.id}/chapters`,
       ],
       ["type", "application/json+chapters"],
     ]),
@@ -88,3 +86,7 @@ function assembleEpisode(options: { series: Series; episode: Episode }) {
 export const rss = {
   assembleFeed,
 };
+
+export const forTestingOnly = {
+  assembleEpisode,
+};
diff --git a/lib/storage.test.ts b/lib/storage.test.ts
index f02eedf..602374f 100644
--- a/lib/storage.test.ts
+++ b/lib/storage.test.ts
@@ -1,4 +1,4 @@
-import { assertEquals } from "asserts";
+import { assertEquals } from "$std/assert/mod.ts";
 import { storage } from "./storage.ts";
 import { testUtils } from "./test-utils.ts";
 
diff --git a/lib/test-utils.ts b/lib/test-utils.ts
index 8d0ea08..23f0755 100644
--- a/lib/test-utils.ts
+++ b/lib/test-utils.ts
@@ -1,5 +1,5 @@
 import { fakerNB_NO as faker } from "npm:@faker-js/faker";
-import { Series } from "./storage.ts";
+import { Episode, Series } from "./storage.ts";
 
 function generateSeries(overrides: Partial<Series> = {}): Series {
   return {
@@ -10,22 +10,29 @@ function generateSeries(overrides: Partial<Series> = {}): Series {
     imageUrl: faker.image.url(),
     lastFetchedAt: faker.date.recent(),
     episodes: new Array(faker.number.int({ min: 0, max: 100 }))
-      .fill(null).map(() => ({
-        title: faker.word.words(3),
-        subtitle: faker.word.words(3),
-        link: faker.internet.url(),
-        description: faker.lorem.paragraphs(2),
-        id: faker.string.uuid(),
-        date: faker.date.recent(),
-        durationInSeconds: faker.number.int({
-          min: 0,
-          max: 3600,
-        }),
-        ...overrides,
-      })),
+      .fill(null).map(() => (generateEpisode(overrides))),
+    ...overrides,
+  };
+}
+
+function generateEpisode(overrides: Partial<Series> = {}): Episode {
+  return {
+    title: faker.word.words(3),
+    subtitle: faker.word.words(3),
+    link: faker.internet.url(),
+    url: faker.internet.url(),
+    shareLink: faker.internet.url(),
+    id: faker.string.uuid(),
+    date: faker.date.recent(),
+    durationInSeconds: faker.number.int({
+      min: 0,
+      max: 3600,
+    }),
+    ...overrides,
   };
 }
 
 export const testUtils = {
   generateSeries,
+  generateEpisode,
 };
diff --git a/lib/utils.ts b/lib/utils.ts
new file mode 100644
index 0000000..f75af7a
--- /dev/null
+++ b/lib/utils.ts
@@ -0,0 +1,31 @@
+import { STATUS_CODE } from "$fresh/server.ts";
+
+export function getHostName() {
+  const deploymentId = Deno.env.get("DENO_DEPLOYMENT_ID");
+  if (deploymentId) {
+    return `https://nrss-${deploymentId}.deno.dev`;
+  } else {
+    // assume env
+    return "http://localhost:8000";
+  }
+}
+
+type EnumValues<T> = T[keyof T];
+type Status = EnumValues<typeof STATUS_CODE>;
+
+export function responseJSON(body: unknown | null, status: Status) {
+  return response(body, status, "json");
+}
+
+export function responseXML(body: unknown | null, status: Status) {
+  return response(body, status, "xml");
+}
+
+function response(body: unknown | null, status: number, type: "json" | "xml") {
+  return new Response(JSON.stringify(body), {
+    status,
+    headers: {
+      "Content-Type": `application/${type}`,
+    },
+  });
+}
diff --git a/routes/api/feeds/[seriesId].ts b/routes/api/feeds/[seriesId].ts
index fa57fdc..39e5161 100644
--- a/routes/api/feeds/[seriesId].ts
+++ b/routes/api/feeds/[seriesId].ts
@@ -1,16 +1,16 @@
-import { FreshContext } from "$fresh/server.ts";
+import { FreshContext, STATUS_CODE } from "$fresh/server.ts";
 import { caching } from "../../../lib/caching.ts";
 import { rss } from "../../../lib/rss.ts";
+import { responseJSON, responseXML } from "../../../lib/utils.ts";
 
 export const handler = async (_req: Request, ctx: FreshContext): Promise<Response> => {
   const seriesId = ctx.params.seriesId;
 
   const series = await caching.getSeries({ id: seriesId });
+  if (!series) {
+    return responseJSON({ message: "Series not found" }, STATUS_CODE.NotFound);
+  }
   const feed = rss.assembleFeed(series);
 
-  return new Response(feed, {
-    headers: {
-      "Content-Type": "application/xml",
-    },
-  });
+  return responseXML(feed, STATUS_CODE.OK);
 };
diff --git a/routes/api/feeds/[seriesId]/[episodeId]/chapters.ts b/routes/api/feeds/[seriesId]/[episodeId]/chapters.ts
index 013fa7f..cf2bfbb 100644
--- a/routes/api/feeds/[seriesId]/[episodeId]/chapters.ts
+++ b/routes/api/feeds/[seriesId]/[episodeId]/chapters.ts
@@ -1,6 +1,7 @@
-import { FreshContext } from "$fresh/server.ts";
+import { FreshContext, STATUS_CODE } from "$fresh/server.ts";
 import { parse, toSeconds } from "https://esm.sh/iso8601-duration@2.1.1";
 import { NrkPodcastEpisode, nrkRadio } from "../../../../../lib/nrk/nrk.ts";
+import { responseJSON } from "../../../../../lib/utils.ts";
 
 type Chapter = {
   title: string | undefined;
@@ -25,12 +26,7 @@ export const handler = async (_req: Request, ctx: FreshContext): Promise<Respons
   const episode = await nrkRadio.getEpisode(seriesId, episodeId);
 
   if (!episode) {
-    return new Response(JSON.stringify({ message: `Episode ${episodeId} is missing` }), {
-      headers: {
-        "Content-Type": "application/json",
-      },
-      status: 500,
-    });
+    return responseJSON({ message: `Episode ${episodeId} is missing` }, STATUS_CODE.NotFound);
   }
   const chapters = toChapters(episode);
   const body = {
@@ -38,9 +34,5 @@ export const handler = async (_req: Request, ctx: FreshContext): Promise<Respons
     chapters,
   };
 
-  return new Response(JSON.stringify(body), {
-    headers: {
-      "Content-Type": "application/json",
-    },
-  });
+  return responseJSON(body, STATUS_CODE.OK);
 };
diff --git a/routes/index.tsx b/routes/index.tsx
index 30f6828..d10efbb 100644
--- a/routes/index.tsx
+++ b/routes/index.tsx
@@ -7,27 +7,26 @@ import SeriesCard from "../components/SeriesCard.tsx";
 import { CSS, render } from "$gfm";
 import { nrkRadio, NrkSearchResultList } from "../lib/nrk/nrk.ts";
 
-interface HandlerData {
-  query: string;
-  origin: string;
+type Props = {
+  query: string | null;
   rawMarkdown: string;
-  result?: NrkSearchResultList;
-}
+  result?: NrkSearchResultList | null;
+};
 
-export const handler: Handlers<HandlerData> = {
+export const handler: Handlers<Props> = {
   async GET(request, ctx) {
     const url = new URL(request.url);
     const query = url.searchParams.get("query");
-    let result: NrkSearchResultList | undefined;
+    let result: Props["result"];
     if (query) {
       result = await nrkRadio.search(query);
     }
     const rawMarkdown = await Deno.readTextFile(new URL("../docs/what.md", import.meta.url));
-    return ctx.render({ query: query || "", result, origin: url.origin, rawMarkdown });
+    return ctx.render({ query, result, rawMarkdown });
   },
 };
 
-export default function Home({ data }: PageProps<HandlerData>) {
+export default function Home({ data, url }: PageProps<Props>) {
   return (
     <>
       <Head>
@@ -46,7 +45,7 @@ export default function Home({ data }: PageProps<HandlerData>) {
       <div className="p-4 mx-auto max-w-screen-md">
         <Header />
         <Search defaultValue={data.query} />
-        <SearchResult result={data.result} origin={data.origin} />
+        <SearchResult result={data.result} origin={url.origin} />
         <div
           class="markdown-body"
           dangerouslySetInnerHTML={{ __html: render(data?.rawMarkdown) }}
@@ -57,7 +56,7 @@ export default function Home({ data }: PageProps<HandlerData>) {
   );
 }
 
-function SearchResult({ result, origin }: { result: NrkSearchResultList; origin: string }) {
+function SearchResult({ result, origin }: { result: Props["result"]; origin: string }) {
   if (!result) {
     return null;
   }
diff --git a/utils.ts b/utils.ts
deleted file mode 100644
index 654e90a..0000000
--- a/utils.ts
+++ /dev/null
@@ -1,9 +0,0 @@
-export function getHostName() {
-  const deploymentId = Deno.env.get("DENO_DEPLOYMENT_ID");
-  if (deploymentId) {
-    return `https://nrss-${deploymentId}.deno.dev`;
-  } else {
-    // assume env
-    return "http://localhost:8000";
-  }
-}