test(caa upload): update Amazon tests

The example release has 5 images, but only 4 thumbnails are shown on
amazon.com by default. Using the embedded JavaScript we can extract
larger images whose filenames contain different identifiers.
Additionally we can also detect the type of the front and the back.
Still testing the thumbnail grabbing (which is now only a fallback) by
mocking the failed attempt of extracting images from the embedded JS.

src/mb_enhanced_cover_art_uploads/providers/amazon.ts

@@ -47,7 +47,7 @@ export class AmazonProvider extends CoverArtProvider {
 
         // For physical products we have to extract the embedded JS from the
         // page source to get all images in their highest available resolution.
-        let covers = this.#extractFromEmbeddedJS(pageContent);
+        let covers = this.extractFromEmbeddedJS(pageContent);
         if (!covers) {
             // Use the (smaller) image thumbnails in the sidebar as a fallback,
             // although it might not contain all of them. IMU will maximise,
@@ -82,7 +82,7 @@ export class AmazonProvider extends CoverArtProvider {
         }];
     }
 
-    #extractFromEmbeddedJS(pageContent: string): CoverArt[] | undefined {
+    extractFromEmbeddedJS(pageContent: string): CoverArt[] | undefined {
         const embeddedImages = pageContent.match(/^'colorImages': { 'initial': (.+)},$/m)?.[1];
         if (embeddedImages) {
             try {

tests/mb_enhanced_cover_art_uploads/providers/amazon.test.ts

@@ -29,19 +29,38 @@ describe('amazon provider', () => {
             .toBe(expectedId);
     });
 
-    it.each`
-        url | desc
-        ${'https://www.amazon.com/dp/B07QWNQT8X'} | ${'dp URLs'}
-        ${'https://www.amazon.com/gp/product/B07QWNQT8X'} | ${'gp URLs'}
-    `('grabs all images for physical products on $desc', async ({ url }: { url: string }) => {
+    const extractionCases = [
+        ['dp URLs', 'https://www.amazon.com/dp/B07QWNQT8X'],
+        ['gp URLs', 'https://www.amazon.com/gp/product/B07QWNQT8X'],
+    ];
+
+    it.each(extractionCases)('grabs all images for physical products from the embedded JS on %s', async (_1, url) => {
+        const covers = await provider.findImages(new URL(url));
+
+        expect(covers).toBeArrayOfSize(5);
+        expect(covers[0].url.pathname).toContain('81bqssuW6LL');
+        expect(covers[0].types).toStrictEqual([ArtworkTypeIDs.Front]);
+        expect(covers[1].url.pathname).toContain('61jZYB6BJYL');
+        expect(covers[1].types).toStrictEqual([ArtworkTypeIDs.Back]);
+        expect(covers[2].url.pathname).toContain('71TLgC33KgL');
+        expect(covers[3].url.pathname).toContain('81JCfIAZ71L');
+        expect(covers[4].url.pathname).toContain('816dglIIJHL');
+    });
+
+    it.each(extractionCases)('falls back to thumbnail grabbing for physical products on %s', async (_1, url) => {
+        // mock the failed attempt of extracting images from embedded JS to trigger the thumbnail fallback
+        const spy = jest.spyOn(provider, 'extractFromEmbeddedJS').mockImplementationOnce(() => undefined);
         const covers = await provider.findImages(new URL(url));
 
         expect(covers).toBeArrayOfSize(4);
         expect(covers[0].url.pathname).toContain('51nM1ikLWPL');
         expect(covers[0].types).toStrictEqual([ArtworkTypeIDs.Front]);
         expect(covers[1].url.pathname).toContain('41RQivjYeeL');
+        expect(covers[1].types).toStrictEqual([ArtworkTypeIDs.Back]);
         expect(covers[2].url.pathname).toContain('31-n8wloCcL');
         expect(covers[3].url.pathname).toMatch(/41MN(?:%2B|\+)eLL(?:%2B|\+)JL/);
+
+        spy.mockRestore();
     });
 
     it('returns no covers for product without images', async () => {