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/packages/utils.test.ts

@@ -0,0 +1,121 @@
+import * as utils from "../../packages/utils";
+import { diagramFactory } from "../fixtures/diagramFixture";
+import * as mockedSceneExportUtils from "../../scene/export";
+
+jest.mock("../../scene/export", () => ({
+  __esmodule: true,
+  ...jest.requireActual("../../scene/export"),
+  exportToSvg: jest.fn(),
+}));
+
+describe("exportToCanvas", () => {
+  const EXPORT_PADDING = 10;
+
+  it("with default arguments", () => {
+    const canvas = utils.exportToCanvas({
+      ...diagramFactory({ elementOverrides: { width: 100, height: 100 } }),
+    });
+
+    expect(canvas.width).toBe(100 + 2 * EXPORT_PADDING);
+    expect(canvas.height).toBe(100 + 2 * EXPORT_PADDING);
+  });
+
+  it("when custom width and height", () => {
+    const canvas = utils.exportToCanvas({
+      ...diagramFactory({ elementOverrides: { width: 100, height: 100 } }),
+      getDimensions: () => ({ width: 200, height: 200, scale: 1 }),
+    });
+
+    expect(canvas.width).toBe(200);
+    expect(canvas.height).toBe(200);
+  });
+});
+
+describe("exportToBlob", () => {
+  describe("mime type", () => {
+    afterEach(jest.restoreAllMocks);
+
+    it("should change image/jpg to image/jpeg", async () => {
+      const blob = await utils.exportToBlob({
+        ...diagramFactory(),
+        getDimensions: (width, height) => ({ width, height, scale: 1 }),
+        mimeType: "image/jpg",
+      });
+      expect(blob?.type).toBe("image/jpeg");
+    });
+
+    it("should default to image/png", async () => {
+      const blob = await utils.exportToBlob({
+        ...diagramFactory(),
+      });
+      expect(blob?.type).toBe("image/png");
+    });
+
+    it("should warn when using quality with image/png", async () => {
+      const consoleSpy = jest
+        .spyOn(console, "warn")
+        .mockImplementationOnce(() => void 0);
+
+      await utils.exportToBlob({
+        ...diagramFactory(),
+        mimeType: "image/png",
+        quality: 1,
+      });
+
+      expect(consoleSpy).toHaveBeenCalledWith(
+        '"quality" will be ignored for "image/png" mimeType',
+      );
+    });
+  });
+});
+
+describe("exportToSvg", () => {
+  const mockedExportUtil = mockedSceneExportUtils.exportToSvg as jest.Mock;
+  const passedElements = () => mockedExportUtil.mock.calls[0][0];
+  const passedOptions = () => mockedExportUtil.mock.calls[0][1];
+
+  afterEach(jest.resetAllMocks);
+
+  it("with default arguments", () => {
+    utils.exportToSvg({
+      ...diagramFactory({
+        overrides: { appState: void 0 },
+      }),
+    });
+
+    const passedOptionsWhenDefault = {
+      ...passedOptions(),
+      // To avoid varying snapshots
+      name: "name",
+    };
+
+    expect(passedElements().length).toBe(3);
+    expect(passedOptionsWhenDefault).toMatchSnapshot();
+  });
+
+  it("with deleted elements", () => {
+    utils.exportToSvg({
+      ...diagramFactory({
+        overrides: { appState: void 0 },
+        elementOverrides: { isDeleted: true },
+      }),
+    });
+
+    expect(passedElements().length).toBe(0);
+  });
+
+  it("with exportPadding and metadata", () => {
+    const METADATA = "some metada";
+
+    utils.exportToSvg({
+      ...diagramFactory({ overrides: { appState: { name: "diagram name" } } }),
+      exportPadding: 0,
+      metadata: METADATA,
+    });
+
+    expect(passedElements().length).toBe(3);
+    expect(passedOptions()).toEqual(
+      expect.objectContaining({ exportPadding: 0, metadata: METADATA }),
+    );
+  });
+});