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

test/integration/freetext_editor_spec.mjs

@@ -2171,20 +2171,13 @@ describe("FreeText Editor", () => {
         "tracemonkey.pdf",
         ".annotationEditorLayer",
         100,
-        async page => {
-          await page.waitForFunction(async () => {
-            await window.PDFViewerApplication.initializedPromise;
-            return true;
-          });
-          await page.evaluate(() => {
+        {
+          eventBusSetup: eventBus => {
             window.visitedPages = [];
-            window.PDFViewerApplication.eventBus.on(
-              "pagechanging",
-              ({ pageNumber }) => {
-                window.visitedPages.push(pageNumber);
-              }
-            );
-          });
+            eventBus.on("pagechanging", ({ pageNumber }) => {
+              window.visitedPages.push(pageNumber);
+            });
+          },
         }
       );
     });
@@ -2403,19 +2396,12 @@ describe("FreeText Editor", () => {
         "tracemonkey.pdf",
         ".annotationEditorLayer",
         100,
-        async page => {
-          await page.waitForFunction(async () => {
-            await window.PDFViewerApplication.initializedPromise;
-            return true;
-          });
-          await page.evaluate(() => {
-            window.PDFViewerApplication.eventBus.on(
-              "annotationeditorstateschanged",
-              ({ details }) => {
-                window.editingEvents?.push(details);
-              }
-            );
-          });
+        {
+          eventBusSetup: eventBus => {
+            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 () => {
-            await window.PDFViewerApplication.initializedPromise;
-            return true;
-          });
-          await page.evaluate(() => {
+        {
+          eventBusSetup: eventBus => {
             window.editingEvents = [];
-            window.PDFViewerApplication.eventBus.on(
-              "annotationeditorstateschanged",
-              ({ details }) => {
-                window.editingEvents.push(details);
-              }
-            );
-          });
+            eventBus.on("annotationeditorstateschanged", ({ 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(
-        "autoprint.pdf",
-        "",
-        null /* zoom = */,
-        async page => {
+      pages = await loadAndWait("autoprint.pdf", "", null /* zoom = */, {
+        postPageSetup: async page => {
           printHandles.set(
             page,
             page.evaluateHandle(() => [
-              new Promise(resolve => {
-                globalThis.printResolve = resolve;
-              }),
+              window.PDFViewerApplication._testPrintResolver.promise,
             ])
           );
-          await page.waitForFunction(() => {
-            // We don't really need to print the document.
-            window.print = () => {};
-            if (!window.PDFViewerApplication?.eventBus) {
-              return false;
-            }
-            window.PDFViewerApplication.eventBus.on(
-              "print",
-              () => {
-                const resolve = globalThis.printResolve;
-                delete globalThis.printResolve;
-                resolve();
-              },
-              { once: true }
-            );
-            return true;
-          });
-        }
-      );
+        },
+        appSetup: app => {
+          app._testPrintResolver = Promise.withResolvers();
+        },
+        eventBusSetup: eventBus => {
+          eventBus.on(
+            "print",
+            () => {
+              window.PDFViewerApplication._testPrintResolver.resolve();
+            },
+            { once: 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 (pageSetup) {
-        await pageSetup(page);
+      if (setups) {
+        // page.evaluateOnNewDocument allows us to run code before the
+        // 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, {