Refactor

src/__test__/index.test.ts

@@ -40,6 +40,9 @@ describe("action", () => {
     jest
       .spyOn(core, "getInput")
       .mockImplementation((name) => defaultInputs[name] || undefined);
+
+    process.env.SpotifyClientID = "test-client-id";
+    process.env.SpotifyClientSecret = "test-client-secret";
   });
 
   test("works", async () => {

src/__test__/list-playlists.test.ts

@@ -29,6 +29,11 @@ jest.mock("spotify-web-api-node", () => {
 jest.mock("@actions/core");
 
 describe("listPlaylists", () => {
+  beforeEach(() => {
+    process.env.SpotifyClientID = "test-client-id";
+    process.env.SpotifyClientSecret = "test-client-secret";
+    jest.clearAllMocks();
+  });
   test("returns", async () => {
     expect(await listPlaylists("2021 Fall")).toMatchInlineSnapshot(`
 {
@@ -177,6 +182,15 @@ describe("listPlaylists", () => {
       'Could not find playlist "2022 Fall". Is it private?'
     );
   });
+
+  test("throw error when SpotifyClientID or SpotifyClientSecret is missing", async () => {
+    delete process.env.SpotifyClientID;
+    delete process.env.SpotifyClientSecret;
+
+    await expect(listPlaylists("2021 Fall")).rejects.toThrow(
+      "Missing SpotifyClientID or SpotifyClientSecret in environment variables"
+    );
+  });
 });
 
 describe("formatTracks", () => {

src/list-playlists.ts

@@ -6,26 +6,11 @@ export default async function listPlaylists(
   listName: string
 ): Promise<Playlist> {
   try {
-    const spotifyApi = new SpotifyWebApi({
-      clientId: process.env.SpotifyClientID,
-      clientSecret: process.env.SpotifyClientSecret,
-    });
+    const spotifyApi = await initializeSpotifyApi();
     const username = getInput("spotify-username");
-    const {
-      body: { access_token },
-    } = await spotifyApi.clientCredentialsGrant();
-
-    spotifyApi.setAccessToken(access_token);
-
-    const { body } = await spotifyApi.getUserPlaylists(username);
-    const findPlaylist = body.items.find(({ name }) => name === listName);
-    if (!findPlaylist) {
-      throw new Error(`Could not find playlist "${listName}". Is it private?`);
-    }
-    const {
-      body: { items },
-    } = await spotifyApi.getPlaylistTracks(findPlaylist.id);
-    if (!items.length) throw new Error("Playlist has no tracks.");
+
+    const findPlaylist = await getPlaylist(spotifyApi, username, listName);
+    const items = await getPlaylistTracks(spotifyApi, findPlaylist.id);
 
     return formatTracks({
       name: findPlaylist.name,
@@ -38,6 +23,58 @@ export default async function listPlaylists(
   }
 }
 
+async function getPlaylist(
+  spotifyApi: SpotifyWebApi,
+  username: string,
+  listName: string
+): Promise<SpotifyApi.PlaylistObjectSimplified> {
+  const { body } = await spotifyApi.getUserPlaylists(username);
+  const findPlaylist = body.items.find(({ name }) => name === listName);
+
+  if (!findPlaylist) {
+    throw new Error(`Could not find playlist "${listName}". Is it private?`);
+  }
+
+  return findPlaylist;
+}
+
+async function getPlaylistTracks(
+  spotifyApi: SpotifyWebApi,
+  playlistId: string
+): Promise<SpotifyApi.PlaylistTrackObject[]> {
+  const {
+    body: { items },
+  } = await spotifyApi.getPlaylistTracks(playlistId);
+
+  if (!items.length) throw new Error("Playlist has no tracks.");
+
+  return items;
+}
+
+export async function initializeSpotifyApi(): Promise<SpotifyWebApi> {
+  const clientId = process.env.SpotifyClientID;
+  const clientSecret = process.env.SpotifyClientSecret;
+
+  if (!clientId || !clientSecret) {
+    throw new Error(
+      "Missing SpotifyClientID or SpotifyClientSecret in environment variables"
+    );
+  }
+
+  const spotifyApi = new SpotifyWebApi({
+    clientId,
+    clientSecret,
+  });
+
+  const {
+    body: { access_token },
+  } = await spotifyApi.clientCredentialsGrant();
+
+  spotifyApi.setAccessToken(access_token);
+
+  return spotifyApi;
+}
+
 export function formatTracks({
   name,
   external_urls,