Set the event handlers in the integration tests before any event is triggered

The function evaluateOnNewDocument in Puppeteer allow us to execute some js before the pdf.js one
is loaded.
It allows us to stub some setters before there are used and then set some event handlers very soon.

test/integration/freetext_editor_spec.mjs

@@ -2171,20 +2171,13 @@ describe("FreeText Editor", () => {
         "tracemonkey.pdf",
         ".annotationEditorLayer",
         100,
-        async page => {
+        {
-          await page.waitForFunction(async () => {
+          eventBusSetup: eventBus => {
-            await window.PDFViewerApplication.initializedPromise;
-            return true;
-          });
-          await page.evaluate(() => {
             window.visitedPages = [];
-            window.PDFViewerApplication.eventBus.on(
+            eventBus.on("pagechanging", ({ pageNumber }) => {
-              "pagechanging",
+              window.visitedPages.push(pageNumber);
-              ({ pageNumber }) => {
+            });
-                window.visitedPages.push(pageNumber);
+          },
-              }
-            );
-          });
         }
       );
     });
@@ -2403,19 +2396,12 @@ describe("FreeText Editor", () => {
         "tracemonkey.pdf",
         ".annotationEditorLayer",
         100,
-        async page => {
+        {
-          await page.waitForFunction(async () => {
+          eventBusSetup: eventBus => {
-            await window.PDFViewerApplication.initializedPromise;
+            eventBus.on("annotationeditorstateschanged", ({ details }) => {
-            return true;
+              window.editingEvents?.push(details);
-          });
+            });
-          await page.evaluate(() => {
+          },
-            window.PDFViewerApplication.eventBus.on(
-              "annotationeditorstateschanged",
-              ({ details }) => {
-                window.editingEvents?.push(details);
-              }
-            );
-          });
         }
       );
     });

test/integration/highlight_editor_spec.mjs

@@ -910,20 +910,13 @@ describe("Highlight Editor", () => {
         "tracemonkey.pdf",
         `.page[data-page-number = "1"] .endOfContent`,
         null,
-        async page => {
+        {
-          await page.waitForFunction(async () => {
+          eventBusSetup: eventBus => {
-            await window.PDFViewerApplication.initializedPromise;
-            return true;
-          });
-          await page.evaluate(() => {
             window.editingEvents = [];
-            window.PDFViewerApplication.eventBus.on(
+            eventBus.on("annotationeditorstateschanged", ({ details }) => {
-              "annotationeditorstateschanged",
+              window.editingEvents.push(details);
-              ({ details }) => {
+            });
-                window.editingEvents.push(details);
+          },
-              }
-            );
-          });
         },
         { highlightEditorColors: "red=#AB0000" }
       );

test/integration/scripting_spec.mjs

@@ -1764,38 +1764,28 @@ describe("Interaction", () => {
       // it is usually very fast and therefore activating the selector check
       // too late will cause it to never resolve because printing is already
       // done (and the printed page div removed) before we even get to it.
-      pages = await loadAndWait(
+      pages = await loadAndWait("autoprint.pdf", "", null /* zoom = */, {
-        "autoprint.pdf",
+        postPageSetup: async page => {
-        "",
-        null /* zoom = */,
-        async page => {
           printHandles.set(
             page,
             page.evaluateHandle(() => [
-              new Promise(resolve => {
+              window.PDFViewerApplication._testPrintResolver.promise,
-                globalThis.printResolve = resolve;
-              }),
             ])
           );
-          await page.waitForFunction(() => {
+        },
-            // We don't really need to print the document.
+        appSetup: app => {
-            window.print = () => {};
+          app._testPrintResolver = Promise.withResolvers();
-            if (!window.PDFViewerApplication?.eventBus) {
+        },
-              return false;
+        eventBusSetup: eventBus => {
-            }
+          eventBus.on(
-            window.PDFViewerApplication.eventBus.on(
+            "print",
-              "print",
+            () => {
-              () => {
+              window.PDFViewerApplication._testPrintResolver.resolve();
-                const resolve = globalThis.printResolve;
+            },
-                delete globalThis.printResolve;
+            { once: true }
-                resolve();
+          );
-              },
+        },
-              { once: true }
+      });
-            );
-            return true;
-          });
-        }
-      );
     });
 
     afterAll(async () => {

test/integration/test_utils.mjs

@@ -14,9 +14,10 @@
  */
 
 import os from "os";
+
 const isMac = os.platform() === "darwin";
 
-function loadAndWait(filename, selector, zoom, pageSetup, options) {
+function loadAndWait(filename, selector, zoom, setups, options) {
   return Promise.all(
     global.integrationSessions.map(async session => {
       const page = await session.browser.newPage();
@@ -52,11 +53,52 @@ function loadAndWait(filename, selector, zoom, pageSetup, options) {
         global.integrationBaseUrl
       }?file=/test/pdfs/${filename}#zoom=${zoom ?? "page-fit"}${app_options}`;
 
-      await page.goto(url);
+      if (setups) {
-      if (pageSetup) {
+        // page.evaluateOnNewDocument allows us to run code before the
-        await pageSetup(page);
+        // first js script is executed.
+        // The idea here is to set up some setters for PDFViewerApplication
+        // and EventBus, so we can inject some code to do whatever we want
+        // soon enough especially before the first event in the eventBus is
+        // dispatched.
+        const { prePageSetup, appSetup, eventBusSetup } = setups;
+        await prePageSetup?.(page);
+        if (appSetup || eventBusSetup) {
+          await page.evaluateOnNewDocument(
+            (aSetup, eSetup) => {
+              let app;
+              let eventBus;
+              Object.defineProperty(window, "PDFViewerApplication", {
+                get() {
+                  return app;
+                },
+                set(newValue) {
+                  app = newValue;
+                  if (aSetup) {
+                    // eslint-disable-next-line no-eval
+                    eval(`(${aSetup})`)(app);
+                  }
+                  Object.defineProperty(app, "eventBus", {
+                    get() {
+                      return eventBus;
+                    },
+                    set(newV) {
+                      eventBus = newV;
+                      // eslint-disable-next-line no-eval
+                      eval(`(${eSetup})`)(eventBus);
+                    },
+                  });
+                },
+              });
+            },
+            appSetup?.toString(),
+            eventBusSetup?.toString()
+          );
+        }
       }
 
+      await page.goto(url);
+      await setups?.postPageSetup?.(page);
+
       await page.bringToFront();
       if (selector) {
         await page.waitForSelector(selector, {