feat: retain seed on shift-paste (#6509)

thanks for the review 👍

src/tests/clipboard.test.tsx

@@ -1,5 +1,10 @@
 import ReactDOM from "react-dom";
-import { render, waitFor, GlobalTestState } from "./test-utils";
+import {
+  render,
+  waitFor,
+  GlobalTestState,
+  createPasteEvent,
+} from "./test-utils";
 import { Pointer, Keyboard } from "./helpers/ui";
 import ExcalidrawApp from "../excalidraw-app";
 import { KEYS } from "../keys";
@@ -9,6 +14,8 @@ import {
 } from "../element/textElement";
 import { getElementBounds } from "../element";
 import { NormalizedZoomValue } from "../types";
+import { API } from "./helpers/api";
+import { copyToClipboard } from "../clipboard";
 
 const { h } = window;
 
@@ -35,38 +42,28 @@ const setClipboardText = (text: string) => {
   });
 };
 
-const sendPasteEvent = () => {
-  const clipboardEvent = new Event("paste", {
-    bubbles: true,
-    cancelable: true,
-    composed: true,
-  });
-
-  // set `clipboardData` properties.
-  // @ts-ignore
-  clipboardEvent.clipboardData = {
-    getData: () => window.navigator.clipboard.readText(),
-    files: [],
-  };
-
+const sendPasteEvent = (text?: string) => {
+  const clipboardEvent = createPasteEvent(
+    text || (() => window.navigator.clipboard.readText()),
+  );
   document.dispatchEvent(clipboardEvent);
 };
 
-const pasteWithCtrlCmdShiftV = () => {
+const pasteWithCtrlCmdShiftV = (text?: string) => {
   Keyboard.withModifierKeys({ ctrl: true, shift: true }, () => {
     //triggering keydown with an empty clipboard
     Keyboard.keyPress(KEYS.V);
     //triggering paste event with faked clipboard
-    sendPasteEvent();
+    sendPasteEvent(text);
   });
 };
 
-const pasteWithCtrlCmdV = () => {
+const pasteWithCtrlCmdV = (text?: string) => {
   Keyboard.withModifierKeys({ ctrl: true }, () => {
     //triggering keydown with an empty clipboard
     Keyboard.keyPress(KEYS.V);
     //triggering paste event with faked clipboard
-    sendPasteEvent();
+    sendPasteEvent(text);
   });
 };
 
@@ -89,6 +86,32 @@ beforeEach(async () => {
   });
 });
 
+describe("general paste behavior", () => {
+  it("should randomize seed on paste", async () => {
+    const rectangle = API.createElement({ type: "rectangle" });
+    const clipboardJSON = (await copyToClipboard([rectangle], null))!;
+
+    pasteWithCtrlCmdV(clipboardJSON);
+
+    await waitFor(() => {
+      expect(h.elements.length).toBe(1);
+      expect(h.elements[0].seed).not.toBe(rectangle.seed);
+    });
+  });
+
+  it("should retain seed on shift-paste", async () => {
+    const rectangle = API.createElement({ type: "rectangle" });
+    const clipboardJSON = (await copyToClipboard([rectangle], null))!;
+
+    // assert we don't randomize seed on shift-paste
+    pasteWithCtrlCmdShiftV(clipboardJSON);
+    await waitFor(() => {
+      expect(h.elements.length).toBe(1);
+      expect(h.elements[0].seed).toBe(rectangle.seed);
+    });
+  });
+});
+
 describe("paste text as single lines", () => {
   it("should create an element for each line when copying with Ctrl/Cmd+V", async () => {
     const text = "sajgfakfn\naaksfnknas\nakefnkasf";

src/tests/flip.test.tsx

@@ -1,5 +1,10 @@
 import ReactDOM from "react-dom";
-import { GlobalTestState, render, waitFor } from "./test-utils";
+import {
+  createPasteEvent,
+  GlobalTestState,
+  render,
+  waitFor,
+} from "./test-utils";
 import { UI, Pointer } from "./helpers/ui";
 import { API } from "./helpers/api";
 import { actionFlipHorizontal, actionFlipVertical } from "../actions";
@@ -680,19 +685,7 @@ describe("freedraw", () => {
 describe("image", () => {
   const createImage = async () => {
     const sendPasteEvent = (file?: File) => {
-      const clipboardEvent = new Event("paste", {
-        bubbles: true,
-        cancelable: true,
-        composed: true,
-      });
-
-      // set `clipboardData` properties.
-      // @ts-ignore
-      clipboardEvent.clipboardData = {
-        getData: () => window.navigator.clipboard.readText(),
-        files: [file],
-      };
-
+      const clipboardEvent = createPasteEvent("", file ? [file] : []);
       document.dispatchEvent(clipboardEvent);
     };
 

src/tests/test-utils.ts

@@ -190,3 +190,24 @@ export const toggleMenu = (container: HTMLElement) => {
   // open menu
   fireEvent.click(container.querySelector(".dropdown-menu-button")!);
 };
+
+export const createPasteEvent = (
+  text:
+    | string
+    | /* getData function */ ((type: string) => string | Promise<string>),
+  files?: File[],
+) => {
+  return Object.assign(
+    new Event("paste", {
+      bubbles: true,
+      cancelable: true,
+      composed: true,
+    }),
+    {
+      clipboardData: {
+        getData: typeof text === "string" ? () => text : text,
+        files: files || [],
+      },
+    },
+  );
+};