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/tests/fixtures/diagramFixture.ts

@@ -0,0 +1,31 @@
+import {
+  diamondFixture,
+  ellipseFixture,
+  rectangleFixture,
+} from "./elementFixture";
+
+export const diagramFixture = {
+  type: "excalidraw",
+  version: 2,
+  source: "https://excalidraw.com",
+  elements: [diamondFixture, ellipseFixture, rectangleFixture],
+  appState: {
+    viewBackgroundColor: "#ffffff",
+    gridSize: null,
+  },
+};
+
+export const diagramFactory = ({
+  overrides = {},
+  elementOverrides = {},
+} = {}) => ({
+  ...diagramFixture,
+  elements: [
+    { ...diamondFixture, ...elementOverrides },
+    { ...ellipseFixture, ...elementOverrides },
+    { ...rectangleFixture, ...elementOverrides },
+  ],
+  ...overrides,
+});
+
+export default diagramFixture;