fix: 🐛 log a warning if local external file is not found

✅ Closes: #174

Author: kaisermann

Diff for: src/modules/parseFile.ts

@@ -42,6 +42,8 @@ export const parseFile = async (
       if (await doesFileExist(path)) {
         content = await getSrcContent(path);
         dependencies.push(path);
+      } else {
+        console.warn(`[svelte-preprocess] The file  "${path}" was not found.`);
       }
     }
   }

Diff for: test/autoProcess/externalFiles.test.ts

@@ -10,6 +10,12 @@ const {
   style: styleProcessor,
 } = getAutoPreprocess();
 
+const REMOTE_JS = [
+  'https://www.example.com/some/externally/delivered/content.js',
+  'http://www.example.com/some/externally/delivered/content.js',
+  '//www.example.com/some/externally/delivered/content.js',
+];
+
 describe('external files', () => {
   let markup: Processed;
   let script: Processed;
@@ -48,15 +54,7 @@ describe('external files', () => {
     expect(style.dependencies).toContain(getFixturePath('style.css'));
   });
 
-  const EXTERNALJS = [
-    'https://www.example.com/some/externally/delivered/content.js',
-    'http://www.example.com/some/externally/delivered/content.js',
-    '//www.example.com/some/externally/delivered/content.js',
-    'some-file.js',
-    './some-not-local-file.js',
-  ];
-
-  EXTERNALJS.forEach((url) => {
+  REMOTE_JS.forEach((url) => {
     it(`should not attempt to locally resolve ${url}`, async () => {
       const input = `<div></div><script src="${url}"></script>`;
 
@@ -66,4 +64,15 @@ describe('external files', () => {
       expect(preprocessed.dependencies).toHaveLength(0);
     });
   });
+
+  it("should throw if local file don't exist", async () => {
+    const spy = jest.spyOn(console, 'warn');
+    const input = `<style src="./missing-potato"></style>`;
+
+    await preprocess(input, getAutoPreprocess());
+
+    expect(spy).toHaveBeenCalledWith(expect.stringContaining('was not found'));
+
+    spy.mockRestore();
+  });
 });

Diff for: test/autoProcess/style.test.ts

@@ -55,7 +55,7 @@ STYLE_LANGS.forEach(([lang, ext]) => {
     });
 
     it(`should return empty if content is empty`, async () => {
-      const templateExternal = `<div></div><style src="./potato/style.${ext}"></style>`;
+      const templateExternal = `<div></div><style lang="${lang}"></style>`;
       const opts = getAutoPreprocess({
         [lang]: {
           sourceMap: false,