chore(pdf-engines): assert at least pdfa or pdfUA is provided

src/pdf-engines/tests/pdf.engine.test.ts

@@ -28,14 +28,16 @@ describe('PDFEngines', () => {
 
     describe('convert', () => {
         describe('when no properties are passed', () => {
-            it('should return a buffer', async () => {
+            it('should throw an error', async () => {
                 mockPromisesAccess.mockResolvedValue();
                 mockFetch.mockResolvedValue(new Response('content'));
-                const buffer = await PDFEngines.convert({
-                    files: ['path/to/file_1.pdf', 'path/to/file_2.pdf']
-                });
-                expect(buffer).toEqual(Buffer.from('content'));
-                expect(mockFormDataAppend).toHaveBeenCalledTimes(2);
+                await expect(
+                    PDFEngines.convert({
+                        files: ['path/to/file_1.pdf', 'path/to/file_2.pdf']
+                    })
+                ).rejects.toThrow(
+                    'At least one of pdfa or pdfUA must be provided'
+                );
             });
         });
 

src/pdf-engines/utils/pdf-engines.utils.ts

@@ -2,7 +2,7 @@ import { constants, createReadStream, promises, ReadStream } from 'fs';
 import path from 'path';
 
 import FormData from 'form-data';
-import { PathLikeOrReadStream } from '../../common';
+import { GotenbergUtils, PathLikeOrReadStream } from '../../common';
 import {
     ConversionOptions,
     MergeOptions
@@ -55,6 +55,11 @@ export class PDFEnginesUtils {
         data: FormData,
         options: ConversionOptions | MergeOptions
     ): Promise<void> {
+        GotenbergUtils.assert(
+            !!options.pdfa || !!options.pdfUA,
+            'At least one of pdfa or pdfUA must be provided'
+        );
+
         if (options.pdfa) {
             data.append('pdfa', options.pdfa);
         }