test: Add unit tests for package/utils (#3357)

* Update return type to reflect actual signature

* add tests

* Set getDimensions as optional

* add newlines between specs

* remove redundant assertion

* move fixtures to separate files

* Add spacing

* Move tests, add cases

* Add unit tests for package/utils exportToSvg

* extract default object in test

* Move test suite to new file

src/packages/utils.ts

@@ -11,7 +11,7 @@ import { restore } from "../data/restore";
 type ExportOpts = {
   elements: readonly ExcalidrawElement[];
   appState?: Partial<Omit<AppState, "offsetTop" | "offsetLeft">>;
-  getDimensions: (
+  getDimensions?: (
     width: number,
     height: number,
   ) => { width: number; height: number; scale: number };
@@ -83,7 +83,7 @@ export const exportToSvg = ({
   appState = getDefaultAppState(),
   exportPadding,
   metadata,
-}: ExportOpts & {
+}: Omit<ExportOpts, "getDimensions"> & {
   exportPadding?: number;
   metadata?: string;
 }): SVGSVGElement => {