diff --git a/core/dialog.ts b/core/dialog.ts
index 7e2112985..ade36aa25 100644
--- a/core/dialog.ts
+++ b/core/dialog.ts
@@ -6,31 +6,6 @@
 
 // Former goog.module ID: Blockly.dialog
 
-let alertImplementation = function (
-  message: string,
-  opt_callback?: () => void,
-) {
-  window.alert(message);
-  if (opt_callback) {
-    opt_callback();
-  }
-};
-
-let confirmImplementation = function (
-  message: string,
-  callback: (result: boolean) => void,
-) {
-  callback(window.confirm(message));
-};
-
-let promptImplementation = function (
-  message: string,
-  defaultValue: string,
-  callback: (result: string | null) => void,
-) {
-  callback(window.prompt(message, defaultValue));
-};
-
 /**
  * Wrapper to window.alert() that app developers may override via setAlert to
  * provide alternatives to the modal browser window.
@@ -38,9 +13,12 @@ let promptImplementation = function (
  * @param message The message to display to the user.
  * @param opt_callback The callback when the alert is dismissed.
  */
-export function alert(message: string, opt_callback?: () => void) {
-  alertImplementation(message, opt_callback);
-}
+export let alert = (message: string, opt_callback?: () => void) => {
+  window.alert(message);
+  if (opt_callback) {
+    opt_callback();
+  }
+};
 
 /**
  * Sets the function to be run when Blockly.dialog.alert() is called.
@@ -48,8 +26,10 @@ export function alert(message: string, opt_callback?: () => void) {
  * @param alertFunction The function to be run.
  * @see Blockly.dialog.alert
  */
-export function setAlert(alertFunction: (p1: string, p2?: () => void) => void) {
-  alertImplementation = alertFunction;
+export function setAlert(
+  alertFunction: (message: string, callback?: () => void) => void,
+) {
+  alert = alertFunction;
 }
 
 /**
@@ -59,16 +39,12 @@ export function setAlert(alertFunction: (p1: string, p2?: () => void) => void) {
  * @param message The message to display to the user.
  * @param callback The callback for handling user response.
  */
-export function confirm(message: string, callback: (p1: boolean) => void) {
-  TEST_ONLY.confirmInternal(message, callback);
-}
-
-/**
- * Private version of confirm for stubbing in tests.
- */
-function confirmInternal(message: string, callback: (p1: boolean) => void) {
-  confirmImplementation(message, callback);
-}
+export let confirm = (
+  message: string,
+  callback: (confirmed: boolean) => void,
+) => {
+  callback(window.confirm(message));
+};
 
 /**
  * Sets the function to be run when Blockly.dialog.confirm() is called.
@@ -77,9 +53,12 @@ function confirmInternal(message: string, callback: (p1: boolean) => void) {
  * @see Blockly.dialog.confirm
  */
 export function setConfirm(
-  confirmFunction: (p1: string, p2: (p1: boolean) => void) => void,
+  confirmFunction: (
+    message: string,
+    callback: (confirmed: boolean) => void,
+  ) => void,
 ) {
-  confirmImplementation = confirmFunction;
+  confirm = confirmFunction;
 }
 
 /**
@@ -92,13 +71,13 @@ export function setConfirm(
  * @param defaultValue The value to initialize the prompt with.
  * @param callback The callback for handling user response.
  */
-export function prompt(
+export let prompt = (
   message: string,
   defaultValue: string,
-  callback: (p1: string | null) => void,
-) {
-  promptImplementation(message, defaultValue, callback);
-}
+  callback: (userInput: string | null) => void,
+) => {
+  callback(window.prompt(message, defaultValue));
+};
 
 /**
  * Sets the function to be run when Blockly.dialog.prompt() is called.
@@ -108,14 +87,10 @@ export function prompt(
  */
 export function setPrompt(
   promptFunction: (
-    p1: string,
-    p2: string,
-    p3: (p1: string | null) => void,
+    message: string,
+    defaultValue: string,
+    callback: (userInput: string | null) => void,
   ) => void,
 ) {
-  promptImplementation = promptFunction;
+  prompt = promptFunction;
 }
-
-export const TEST_ONLY = {
-  confirmInternal,
-};
diff --git a/tests/mocha/contextmenu_items_test.js b/tests/mocha/contextmenu_items_test.js
index 4596513c6..ef1a9530c 100644
--- a/tests/mocha/contextmenu_items_test.js
+++ b/tests/mocha/contextmenu_items_test.js
@@ -322,10 +322,10 @@ suite('Context Menu Items', function () {
       });
 
       test('Deletes all blocks after confirming', function () {
-        // Mocks the confirmation dialog and calls the callback with 'true' simulating ok.
-        const confirmStub = sinon
-          .stub(Blockly.dialog.TEST_ONLY, 'confirmInternal')
-          .callsArgWith(1, true);
+        // Mocks the confirmation dialog and calls the callback with 'true'
+        // simulating ok.
+        const confirmStub = sinon.stub().callsArgWith(1, true);
+        Blockly.dialog.setConfirm(confirmStub);
 
         this.workspace.newBlock('text');
         this.workspace.newBlock('text');
@@ -337,9 +337,8 @@ suite('Context Menu Items', function () {
 
       test('Does not delete blocks if not confirmed', function () {
         // Mocks the confirmation dialog and calls the callback with 'false' simulating cancel.
-        const confirmStub = sinon
-          .stub(Blockly.dialog.TEST_ONLY, 'confirmInternal')
-          .callsArgWith(1, false);
+        const confirmStub = sinon.stub().callsArgWith(1, false);
+        Blockly.dialog.setConfirm(confirmStub);
 
         this.workspace.newBlock('text');
         this.workspace.newBlock('text');
@@ -350,10 +349,9 @@ suite('Context Menu Items', function () {
       });
 
       test('No dialog for single block', function () {
-        const confirmStub = sinon.stub(
-          Blockly.dialog.TEST_ONLY,
-          'confirmInternal',
-        );
+        const confirmStub = sinon.stub();
+        Blockly.dialog.setConfirm(confirmStub);
+
         this.workspace.newBlock('text');
         this.deleteOption.callback(this.scope);
         this.clock.runAll();
diff --git a/tests/mocha/dialog_test.js b/tests/mocha/dialog_test.js
new file mode 100644
index 000000000..22831c58d
--- /dev/null
+++ b/tests/mocha/dialog_test.js
@@ -0,0 +1,58 @@
+/**
+ * @license
+ * Copyright 2024 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+suite.only('Dialog', function () {
+  teardown(function () {
+    sinon.restore();
+  });
+
+  suite('Prompt', function () {
+    test('setPrompt can take in a function with additional parameters', function () {
+      const spy = sinon.spy();
+      Blockly.dialog.setPrompt(spy);
+      const callback = () => {};
+
+      Blockly.dialog.prompt(
+        'message',
+        'defaultVal',
+        callback,
+        'extra parameter',
+      );
+
+      chai.assert.isTrue(
+        spy.calledWith('message', 'defaultVal', callback, 'extra parameter'),
+      );
+    });
+  });
+
+  suite('Confirm', function () {
+    test('setConfirm can take in a function with additional parameters', function () {
+      const spy = sinon.spy();
+      Blockly.dialog.setConfirm(spy);
+      const callback = () => {};
+
+      Blockly.dialog.confirm('message', callback, 'extra parameter');
+
+      chai.assert.isTrue(
+        spy.calledWith('message', callback, 'extra parameter'),
+      );
+    });
+  });
+
+  suite('Alert', function () {
+    test('setAlert can take in a function with additional parameters', function () {
+      const spy = sinon.spy();
+      Blockly.dialog.setAlert(spy);
+      const callback = () => {};
+
+      Blockly.dialog.alert('message', callback, 'extra parameter');
+
+      chai.assert.isTrue(
+        spy.calledWith('message', callback, 'extra parameter'),
+      );
+    });
+  });
+});
diff --git a/tests/mocha/index.html b/tests/mocha/index.html
index 9c7b10cab..34738605a 100644
--- a/tests/mocha/index.html
+++ b/tests/mocha/index.html
@@ -52,6 +52,7 @@
       import './contextmenu_items_test.js';
       import './contextmenu_test.js';
       import './cursor_test.js';
+      import './dialog_test.js';
       import './dropdowndiv_test.js';
       import './event_test.js';
       import './event_block_change_test.js';
diff --git a/tests/mocha/test_helpers/workspace.js b/tests/mocha/test_helpers/workspace.js
index 6da113f8b..ce8822019 100644
--- a/tests/mocha/test_helpers/workspace.js
+++ b/tests/mocha/test_helpers/workspace.js
@@ -99,9 +99,8 @@ export function testAWorkspace() {
 
     test('deleteVariableById(id2) one usage', function () {
       // Deleting variable one usage should not trigger confirm dialog.
-      const stub = sinon
-        .stub(Blockly.dialog.TEST_ONLY, 'confirmInternal')
-        .callsArgWith(1, true);
+      const stub = sinon.stub().callsArgWith(1, true);
+      Blockly.dialog.setConfirm(stub);
       this.workspace.deleteVariableById('id2');
 
       sinon.assert.notCalled(stub);
@@ -113,9 +112,8 @@ export function testAWorkspace() {
 
     test('deleteVariableById(id1) multiple usages confirm', function () {
       // Deleting variable with multiple usages triggers confirm dialog.
-      const stub = sinon
-        .stub(Blockly.dialog.TEST_ONLY, 'confirmInternal')
-        .callsArgWith(1, true);
+      const stub = sinon.stub().callsArgWith(1, true);
+      Blockly.dialog.setConfirm(stub);
       this.workspace.deleteVariableById('id1');
 
       sinon.assert.calledOnce(stub);
@@ -127,9 +125,8 @@ export function testAWorkspace() {
 
     test('deleteVariableById(id1) multiple usages cancel', function () {
       // Deleting variable with multiple usages triggers confirm dialog.
-      const stub = sinon
-        .stub(Blockly.dialog.TEST_ONLY, 'confirmInternal')
-        .callsArgWith(1, false);
+      const stub = sinon.stub().callsArgWith(1, false);
+      Blockly.dialog.setConfirm(stub);
       this.workspace.deleteVariableById('id1');
 
       sinon.assert.calledOnce(stub);