diff --git a/packages/@lwc/integration-not-karma/configs/plugins/serve-integration.js b/packages/@lwc/integration-not-karma/configs/plugins/serve-integration.js
index 3864925f65..0f0a0cd1c7 100644
--- a/packages/@lwc/integration-not-karma/configs/plugins/serve-integration.js
+++ b/packages/@lwc/integration-not-karma/configs/plugins/serve-integration.js
@@ -32,12 +32,8 @@ const createRollupPlugin = (input, options) => {
         enableStaticContentOptimization: !DISABLE_STATIC_CONTENT_OPTIMIZATION,
         disableSyntheticShadowSupport: DISABLE_SYNTHETIC_SHADOW_SUPPORT_IN_COMPILER,
         apiVersion: API_VERSION,
-        modules: [
-            {
-                // Assume `ctx.path` is a component file, e.g. modules/x/foo/foo.js
-                dir: path.resolve(input, '../../..'),
-            },
-        ],
+        // Assume `ctx.path` is a component file, e.g. modules/x/foo/foo.js
+        modules: [{ dir: path.resolve(input, '../../..') }],
         ...options,
     });
 };
@@ -85,6 +81,7 @@ const transform = async (ctx) => {
         plugins: [customLwcRollupPlugin],
 
         external: [
+            '@vitest/spy',
             'lwc',
             'wire-service',
             // Some helper files export functions that mutate a global state. The setup file calls
diff --git a/packages/@lwc/integration-not-karma/configs/plugins/test-hydration.js b/packages/@lwc/integration-not-karma/configs/plugins/test-hydration.js
index 96d0371034..01e8a6fa6d 100644
--- a/packages/@lwc/integration-not-karma/configs/plugins/test-hydration.js
+++ b/packages/@lwc/integration-not-karma/configs/plugins/test-hydration.js
@@ -1,5 +1,5 @@
+import { spyOn } from '@vitest/spy';
 import * as LWC from 'lwc';
-import { spyConsole } from '../../helpers/console';
 import { setHooks } from '../../helpers/hooks';
 
 setHooks({ sanitizeHtmlContent: (content) => content });
@@ -8,6 +8,28 @@ function parseStringToDom(html) {
     return Document.parseHTMLUnsafe(html).body.firstChild;
 }
 
+/**
+ * A much simplified version of the spies originally used for Karma.
+ * Should probably be eventually replaced with individual spies.
+ */
+export function spyConsole() {
+    const log = spyOn(console, 'log');
+    const warn = spyOn(console, 'warn');
+    const error = spyOn(console, 'error');
+    return {
+        calls: {
+            log: log.mock.calls,
+            warn: warn.mock.calls,
+            error: error.mock.calls,
+        },
+        reset() {
+            log.mockRestore();
+            warn.mockRestore();
+            error.mockRestore();
+        },
+    };
+}
+
 function appendTestTarget(ssrText) {
     const div = document.createElement('div');
     const testTarget = parseStringToDom(ssrText);
diff --git a/packages/@lwc/integration-not-karma/helpers/console.js b/packages/@lwc/integration-not-karma/helpers/console.js
deleted file mode 100644
index 9a52018dcb..0000000000
--- a/packages/@lwc/integration-not-karma/helpers/console.js
+++ /dev/null
@@ -1,23 +0,0 @@
-import { spyOn } from '@vitest/spy';
-
-/**
- * A much simplified version of the spies originally used for Karma.
- * Should probably be eventually replaced with individual spies.
- */
-export function spyConsole() {
-    const log = spyOn(console, 'log');
-    const warn = spyOn(console, 'warn');
-    const error = spyOn(console, 'error');
-    return {
-        calls: {
-            log: log.mock.calls,
-            warn: warn.mock.calls,
-            error: error.mock.calls,
-        },
-        reset() {
-            log.mockRestore();
-            warn.mockRestore();
-            error.mockRestore();
-        },
-    };
-}
diff --git a/packages/@lwc/integration-not-karma/test/api/CustomElementConstructor-getter/index.spec.js b/packages/@lwc/integration-not-karma/test/api/CustomElementConstructor-getter/index.spec.js
index 5d224c512c..6850011af9 100644
--- a/packages/@lwc/integration-not-karma/test/api/CustomElementConstructor-getter/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/api/CustomElementConstructor-getter/index.spec.js
@@ -9,7 +9,7 @@ import AttrChanged from 'x/attrChanged';
 import ReflectCamel from 'x/reflectCamel';
 import WithChildElmsHasSlot from 'x/withChildElmsHasSlot';
 import WithChildElmsHasSlotLight from 'x/withChildElmsHasSlotLight';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 import { USE_COMMENTS_FOR_FRAGMENT_BOOKENDS } from '../../../helpers/constants.js';
 
 const vFragBookend = USE_COMMENTS_FOR_FRAGMENT_BOOKENDS ? '<!---->' : '';
@@ -69,19 +69,9 @@ it('should create custom element if it exists before customElements.define', ()
 describe('non-empty custom element', () => {
     let consoleSpy;
     beforeEach(() => {
-        consoleSpy = spyConsole();
+        consoleSpy = spyOn(console, 'warn').mockImplementation(() => {});
     });
-    afterEach(() => {
-        consoleSpy.reset();
-    });
-
-    function expectWarnings(expectedWarnings) {
-        const observedWarnings = consoleSpy.calls.warn
-            .flat()
-            .map((err) => (err instanceof Error ? err.message : err));
-
-        expect(observedWarnings).toEqual(expectedWarnings);
-    }
+    afterEach(() => consoleSpy.mockRestore());
 
     it('should log error if non-native-shadow custom element has children', () => {
         const elm = document.createElement('test-custom-element-preexisting2');
@@ -93,11 +83,11 @@ describe('non-empty custom element', () => {
             class extends WithChildElms.CustomElementConstructor {}
         );
         if (process.env.NODE_ENV !== 'production' && !process.env.NATIVE_SHADOW) {
-            expectWarnings([
-                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.',
-            ]);
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.'
+            );
         } else {
-            expectWarnings([]);
+            expect(consoleSpy).not.toHaveBeenCalled();
         }
 
         expect(elm.shadowRoot.childNodes.length).toBe(1);
@@ -123,11 +113,11 @@ describe('non-empty custom element', () => {
         );
 
         if (process.env.NODE_ENV !== 'production') {
-            expectWarnings([
-                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.',
-            ]);
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.'
+            );
         } else {
-            expectWarnings([]);
+            expect(consoleSpy).not.toHaveBeenCalled();
         }
 
         expect(elm.innerHTML).toBe(`${vFragBookend}${vFragBookend}`);
@@ -143,11 +133,11 @@ describe('non-empty custom element', () => {
             class extends WithChildElmsHasSlot.CustomElementConstructor {}
         );
         if (process.env.NODE_ENV !== 'production' && !process.env.NATIVE_SHADOW) {
-            expectWarnings([
-                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.',
-            ]);
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.'
+            );
         } else {
-            expectWarnings([]);
+            expect(consoleSpy).not.toHaveBeenCalled();
         }
 
         expect(elm.shadowRoot.childNodes.length).toBe(1);
@@ -174,11 +164,11 @@ describe('non-empty custom element', () => {
         );
 
         if (process.env.NODE_ENV === 'production') {
-            expectWarnings([]);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expectWarnings([
-                'Found an existing shadow root for the custom element "Child". Call `hydrateComponent` instead.',
-            ]);
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                'Found an existing shadow root for the custom element "Child". Call `hydrateComponent` instead.'
+            );
         }
         expect(elm.shadowRoot.innerHTML).toBe('<div></div>');
     });
@@ -194,11 +184,11 @@ describe('non-empty custom element', () => {
         document.body.appendChild(elm);
 
         if (process.env.NODE_ENV !== 'production' && !process.env.NATIVE_SHADOW) {
-            expectWarnings([
-                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.',
-            ]);
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                'Light DOM and synthetic shadow custom elements cannot have child nodes. Ensure the element is empty, including whitespace.'
+            );
         } else {
-            expectWarnings([]);
+            expect(consoleSpy).not.toHaveBeenCalled();
         }
 
         expect(elm.childNodes.length).toBe(1);
diff --git a/packages/@lwc/integration-not-karma/test/component/LightningElement.addEventListener/index.spec.js b/packages/@lwc/integration-not-karma/test/component/LightningElement.addEventListener/index.spec.js
index 2b10f0152f..2f5c7c9cdf 100644
--- a/packages/@lwc/integration-not-karma/test/component/LightningElement.addEventListener/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/component/LightningElement.addEventListener/index.spec.js
@@ -3,7 +3,7 @@ import { createElement } from 'lwc';
 import EventHandler from 'x/eventHandler';
 import EventHandlerOptions from 'x/eventHandlerOptions';
 import AdditionWhileDispatch from 'x/additionWhileDispatch';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 
 it('should be able to attach an event listener on the host element', () => {
     let thisValue;
@@ -39,12 +39,11 @@ it('should warn when passing a 3rd parameter to the event handler', () => {
 
 describe('event handler is not a function', () => {
     let consoleSpy;
-    beforeEach(() => {
-        consoleSpy = spyConsole();
-    });
-    afterEach(() => {
-        consoleSpy.reset();
+    beforeAll(() => {
+        consoleSpy = spyOn(console, 'error');
     });
+    afterEach(() => consoleSpy.mockReset());
+    afterAll(() => consoleSpy.mockRestore());
 
     it('should log an error if event handler is not a function', () => {
         const elm = createElement('x-event-handler', { is: EventHandler });
@@ -54,11 +53,10 @@ describe('event handler is not a function', () => {
         }).toThrowCallbackReactionError(/Expected an EventListener but received undefined/);
 
         if (process.env.NODE_ENV === 'production') {
-            expect(consoleSpy.calls.error.length).toEqual(0);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expect(consoleSpy.calls.error.length).toEqual(1);
-            expect(consoleSpy.calls.error[0][0].message).toContain(
-                'Invalid second argument for this.addEventListener()'
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                expect.stringContaining('Invalid second argument for this.addEventListener()')
             );
         }
     });
diff --git a/packages/@lwc/integration-not-karma/test/component/dynamic-imports/index.spec.js b/packages/@lwc/integration-not-karma/test/component/dynamic-imports/index.spec.js
index 640bd51eea..23d79a92b8 100644
--- a/packages/@lwc/integration-not-karma/test/component/dynamic-imports/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/component/dynamic-imports/index.spec.js
@@ -10,7 +10,7 @@ import LwcDynamicSlotted from 'x/lwcDynamicSlotted';
 import ContainerFoo from 'x/containerFoo';
 import ContainerBar from 'x/containerBar';
 
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 import { registerForLoad, clearRegister } from '../../../helpers/dynamic-loader.js';
 
 beforeEach(() => {
@@ -116,12 +116,10 @@ it('should not cache DOM elements using lwc:dynamic', async () => {
 
 describe('slotted content using lwc:dynamic', () => {
     let consoleSpy;
-    beforeEach(() => {
-        consoleSpy = spyConsole();
-    });
-    afterEach(() => {
-        consoleSpy.reset();
+    beforeAll(() => {
+        consoleSpy = spyOn(console, 'error');
     });
+    afterAll(() => consoleSpy.mockRestore());
 
     it('reallocate slotted content after changing constructor', async () => {
         const elm = createElement('x-dynamic-slotted', { is: LwcDynamicSlotted });
@@ -136,7 +134,7 @@ describe('slotted content using lwc:dynamic', () => {
             // `slot-bar` is not rendered in synthetic shadow
             expect(elm.shadowRoot.querySelector('[data-id="slot-bar"]').assignedSlot).toBe(null);
         }
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
 
         // Swap construstor and check if nodes have been reallocated.
         elm.ctor = ContainerBar;
@@ -150,7 +148,7 @@ describe('slotted content using lwc:dynamic', () => {
             // `slot-foo` is not rendered in synthetic shadow
             expect(elm.shadowRoot.querySelector('[data-id="slot-foo"]').assignedSlot).toBe(null);
         }
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
     });
 });
 
@@ -242,12 +240,10 @@ it('should not cache DOM elements', async () => {
 
 describe('slotted content', () => {
     let consoleSpy;
-    beforeEach(() => {
-        consoleSpy = spyConsole();
-    });
-    afterEach(() => {
-        consoleSpy.reset();
+    beforeAll(() => {
+        consoleSpy = spyOn(console, 'error');
     });
+    afterAll(() => consoleSpy.mockRestore());
 
     it('reallocate slotted content after changing constructor', async () => {
         const elm = createElement('x-dynamic-slotted', { is: DynamicSlotted });
@@ -262,7 +258,7 @@ describe('slotted content', () => {
             // `slot-bar` is not rendered in synthetic shadow
             expect(elm.shadowRoot.querySelector('[data-id="slot-bar"]').assignedSlot).toBe(null);
         }
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
 
         // Swap constructor and check if nodes have been reallocated.
         elm.ctor = ContainerBar;
@@ -276,6 +272,6 @@ describe('slotted content', () => {
             // `slot-foo` is not rendered in synthetic shadow
             expect(elm.shadowRoot.querySelector('[data-id="slot-foo"]').assignedSlot).toBe(null);
         }
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
     });
 });
diff --git a/packages/@lwc/integration-not-karma/test/lwc-on/index.spec.js b/packages/@lwc/integration-not-karma/test/lwc-on/index.spec.js
index d62d43e081..32a1562a25 100644
--- a/packages/@lwc/integration-not-karma/test/lwc-on/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/lwc-on/index.spec.js
@@ -11,8 +11,8 @@ import RerenderLoop from 'x/rerenderLoop';
 import PublicProp from 'x/publicProp';
 import ComputedKey from 'x/computedKey';
 import ValueEvaluationThrows from 'x/valueEvaluationThrows';
+import { spyOn } from '@vitest/spy';
 import { jasmine } from '../../helpers/jasmine.js';
-import { spyConsole } from '../../helpers/console.js';
 import { catchUnhandledRejectionsAndErrors } from '../../helpers/utils.js';
 
 describe('lwc:on', () => {
@@ -257,10 +257,10 @@ describe('lwc:on', () => {
             describe('with same object modified', () => {
                 let consoleSpy;
                 beforeEach(() => {
-                    consoleSpy = spyConsole();
+                    consoleSpy = spyOn(console, 'error').mockImplementation(() => {});
                 });
                 afterEach(() => {
-                    consoleSpy.reset();
+                    consoleSpy.mockRestore();
                 });
 
                 it('throws when a new property is added to object passed to lwc:on', async () => {
@@ -268,12 +268,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'mouseover' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'mouseover' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
 
@@ -282,12 +286,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
 
@@ -296,12 +304,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
             });
@@ -348,10 +360,10 @@ describe('lwc:on', () => {
             describe('with same object modified', () => {
                 let consoleSpy;
                 beforeEach(() => {
-                    consoleSpy = spyConsole();
+                    consoleSpy = spyOn(console, 'error').mockImplementation(() => {});
                 });
                 afterEach(() => {
-                    consoleSpy.reset();
+                    consoleSpy.mockRestore();
                 });
 
                 it('throws when a new property is added to object passed to lwc:on', async () => {
@@ -359,12 +371,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'mouseover' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'mouseover' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
 
@@ -373,12 +389,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
 
@@ -387,12 +407,16 @@ describe('lwc:on', () => {
                     await element.triggerReRender();
 
                     if (process.env.NODE_ENV !== 'production') {
-                        expect(consoleSpy.calls.error.length).toEqual(1);
-                        expect(consoleSpy.calls.error[0][0].message).toContain(
-                            "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                        expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                            expect.objectContaining({
+                                message: expect.stringContaining(
+                                    "Detected mutation of property 'click' in the object passed to lwc:on for <button>. Reusing the same object with modified properties is prohibited. Please pass a new object instead."
+                                ),
+                            })
                         );
                     } else {
-                        expect(consoleSpy.calls.error.length).toEqual(0);
+                        expect(consoleSpy).not.toHaveBeenCalled();
                     }
                 });
             });
diff --git a/packages/@lwc/integration-not-karma/test/regression/invalid-key/index.spec.js b/packages/@lwc/integration-not-karma/test/regression/invalid-key/index.spec.js
index 313cd894ef..4d5ad6eab6 100644
--- a/packages/@lwc/integration-not-karma/test/regression/invalid-key/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/regression/invalid-key/index.spec.js
@@ -1,7 +1,15 @@
 import { createElement } from 'lwc';
 import ConditionalList from 'x/conditionalList';
+import { spyOn } from '@vitest/spy';
 import { extractDataIds } from '../../../helpers/utils.js';
-import { spyConsole } from '../../../helpers/console.js';
+
+let consoleSpy;
+beforeEach(() => {
+    consoleSpy = spyOn(console, 'error');
+});
+afterEach(() => {
+    consoleSpy.mockRestore();
+});
 
 it('W-15885661 - renders list when key is invalid (preserve backwards compat)', async () => {
     const elm = createElement('x-conditional-list', { is: ConditionalList });
@@ -12,18 +20,21 @@ it('W-15885661 - renders list when key is invalid (preserve backwards compat)',
     // Empty fragment
     expect(ul.children.length).toBe(0);
 
-    const spy = spyConsole();
     elm.items = [{ value: 1 }];
     await Promise.resolve();
 
-    const errorCalls = spy.calls.error;
-    expect(errorCalls.length).toBe(process.env.NODE_ENV === 'production' ? 0 : 2);
-    errorCalls.forEach(([error]) => {
-        expect(error).toBeInstanceOf(Error);
-        expect(error.message).toMatch(/(Invalid key value.*|Invalid "key" attribute.*)/);
-    });
-
-    spy.reset();
+    if (process.env.NODE_ENV === 'production') {
+        expect(consoleSpy).not.toHaveBeenCalled();
+    } else {
+        expect(consoleSpy).toHaveBeenCalledTimes(2);
+        const [firstCall, secondCall] = consoleSpy.mock.calls;
+        expect(firstCall).toHaveSize(1);
+        expect(firstCall[0]).toBeInstanceOf(Error);
+        expect(firstCall[0].message).toContain('Invalid key value');
+        expect(secondCall).toHaveSize(1);
+        expect(secondCall[0]).toBeInstanceOf(Error);
+        expect(secondCall[0].message).toContain('Invalid "key" attribute');
+    }
 
     // Still renders list with invalid keys
     expect(ul.children.length).toBe(1);
diff --git a/packages/@lwc/integration-not-karma/test/rendering/side-effects/index.spec.js b/packages/@lwc/integration-not-karma/test/rendering/side-effects/index.spec.js
index 070b6ba1cc..c8fe342a30 100644
--- a/packages/@lwc/integration-not-karma/test/rendering/side-effects/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/rendering/side-effects/index.spec.js
@@ -4,15 +4,15 @@ import SideEffectDuringRender from 'x/sideEffectDuringRender';
 import SideEffectDuringTemplate from 'x/sideEffectDuringTemplate';
 import SideEffectDuringRenderExternal from 'x/sideEffectDuringRenderExternal';
 import SideEffectDuringTemplateExternal from 'x/sideEffectDuringTemplateExternal';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 
 describe('side effects', () => {
     let consoleSpy;
     beforeEach(() => {
-        consoleSpy = spyConsole();
+        consoleSpy = spyOn(console, 'error');
     });
     afterEach(() => {
-        consoleSpy.reset();
+        consoleSpy.mockRestore();
     });
 
     it('logs error for side effect during render', async () => {
@@ -22,11 +22,15 @@ describe('side effects', () => {
         await Promise.resolve();
 
         if (process.env.NODE_ENV === 'production') {
-            expect(consoleSpy.calls.error.length).toEqual(0);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expect(consoleSpy.calls.error.length).toEqual(1);
-            expect(consoleSpy.calls.error[0][0].message).toContain(
-                'render() method has side effects on the state of property "foo"'
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                expect.objectContaining({
+                    message: expect.stringContaining(
+                        'render() method has side effects on the state of property "foo"'
+                    ),
+                })
             );
         }
     });
@@ -40,11 +44,15 @@ describe('side effects', () => {
         await Promise.resolve();
 
         if (process.env.NODE_ENV === 'production') {
-            expect(consoleSpy.calls.error.length).toEqual(0);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expect(consoleSpy.calls.error.length).toEqual(1);
-            expect(consoleSpy.calls.error[0][0].message).toContain(
-                'Updating the template has side effects on the state of property "foo"'
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                expect.objectContaining({
+                    message: expect.stringContaining(
+                        'Updating the template has side effects on the state of property "foo"'
+                    ),
+                })
             );
         }
     });
@@ -57,18 +65,22 @@ describe('side effects', () => {
 
         await Promise.resolve();
 
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
 
         elm.bar = 1; // force re-render
 
         await Promise.resolve();
 
         if (process.env.NODE_ENV === 'production') {
-            expect(consoleSpy.calls.error.length).toEqual(0);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expect(consoleSpy.calls.error.length).toEqual(1);
-            expect(consoleSpy.calls.error[0][0].message).toContain(
-                'render() method has side effects on the state of property "baz"'
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                expect.objectContaining({
+                    message: expect.stringContaining(
+                        'render() method has side effects on the state of property "baz"'
+                    ),
+                })
             );
         }
     });
@@ -81,18 +93,22 @@ describe('side effects', () => {
 
         await Promise.resolve();
 
-        expect(consoleSpy.calls.error.length).toEqual(0);
+        expect(consoleSpy).not.toHaveBeenCalled();
 
         elm.bar = 1; // force re-render
 
         await Promise.resolve();
 
         if (process.env.NODE_ENV === 'production') {
-            expect(consoleSpy.calls.error.length).toEqual(0);
+            expect(consoleSpy).not.toHaveBeenCalled();
         } else {
-            expect(consoleSpy.calls.error.length).toEqual(1);
-            expect(consoleSpy.calls.error[0][0].message).toContain(
-                'Updating the template has side effects on the state of property "baz"'
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+            expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                expect.objectContaining({
+                    message: expect.stringContaining(
+                        'Updating the template has side effects on the state of property "baz"'
+                    ),
+                })
             );
         }
     });
diff --git a/packages/@lwc/integration-not-karma/test/rendering/slotting/index.spec.js b/packages/@lwc/integration-not-karma/test/rendering/slotting/index.spec.js
index f991f890b3..65f94ade42 100644
--- a/packages/@lwc/integration-not-karma/test/rendering/slotting/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/rendering/slotting/index.spec.js
@@ -5,7 +5,7 @@ import RegressionContainer from 'x/regressionContainer';
 import FallbackContentReuseDynamicKeyParent from 'x/fallbackContentReuseDynamicKeyParent';
 import UnknownSlotShadow from 'x/unknownSlotShadow';
 import UnknownSlotLight from 'x/unknownSlotLight';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 
 // TODO [#1617]: Engine currently has trouble with slotting and invocation of the renderedCallback.
 xit('should not render if the slotted content changes', () => {
@@ -78,12 +78,15 @@ it('should not throw error when updating slotted content triggers next tick re-r
 });
 
 describe('does not log an error/warning on unknown slot name', () => {
-    let consoleSpy;
+    let warnSpy;
+    let errorSpy;
     beforeEach(() => {
-        consoleSpy = spyConsole();
+        warnSpy = spyOn(console, 'warn');
+        errorSpy = spyOn(console, 'error');
     });
     afterEach(() => {
-        consoleSpy.reset();
+        warnSpy.mockRestore();
+        errorSpy.mockRestore();
     });
 
     it('shadow dom', async () => {
@@ -100,8 +103,8 @@ describe('does not log an error/warning on unknown slot name', () => {
                 .assignedNodes().length
         ).toEqual(0);
 
-        expect(consoleSpy.calls.error.length).toEqual(0);
-        expect(consoleSpy.calls.warn.length).toEqual(0);
+        expect(warnSpy).not.toHaveBeenCalled();
+        expect(errorSpy).not.toHaveBeenCalled();
     });
 
     it('light dom', async () => {
@@ -113,7 +116,7 @@ describe('does not log an error/warning on unknown slot name', () => {
         // nothing slotted into the child
         expect(elm.querySelector('x-unknown-slot-light-child').children.length).toEqual(0);
 
-        expect(consoleSpy.calls.error.length).toEqual(0);
-        expect(consoleSpy.calls.warn.length).toEqual(0);
+        expect(warnSpy).not.toHaveBeenCalled();
+        expect(errorSpy).not.toHaveBeenCalled();
     });
 });
diff --git a/packages/@lwc/integration-not-karma/test/signal/untrusted/index.spec.js b/packages/@lwc/integration-not-karma/test/signal/untrusted/index.spec.js
index f7c4ee9aaf..cf603daae3 100644
--- a/packages/@lwc/integration-not-karma/test/signal/untrusted/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/signal/untrusted/index.spec.js
@@ -2,7 +2,7 @@ import { createElement, setFeatureFlagForTest } from 'lwc';
 
 import Test from 'x/test';
 import { Signal } from 'x/signal';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 
 const createElementSignalAndInsertIntoDom = async (object) => {
     const elm = createElement('x-test', { is: Test });
@@ -17,8 +17,10 @@ describe('signal reaction in lwc', () => {
 
     beforeAll(() => setFeatureFlagForTest('ENABLE_EXPERIMENTAL_SIGNALS', true));
     afterAll(() => setFeatureFlagForTest('ENABLE_EXPERIMENTAL_SIGNALS', false));
-    beforeEach(() => (consoleSpy = spyConsole()));
-    afterEach(() => consoleSpy.reset());
+    beforeEach(() => {
+        consoleSpy = spyOn(console, 'warn');
+    });
+    afterEach(() => consoleSpy.mockRestore());
 
     describe('with trusted signal set', () => {
         describe('ENABLE_LEGACY_SIGNAL_CONTEXT_VALIDATION is enabled', () => {
@@ -28,13 +30,13 @@ describe('signal reaction in lwc', () => {
                 const elm = await createElementSignalAndInsertIntoDom({
                     value: 'non signal value',
                 });
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 expect(elm.shadowRoot.textContent).toBe('non signal value');
             });
             it('will not warn if rendering signal objects', async () => {
                 const signal = new Signal('signal value');
                 const elm = await createElementSignalAndInsertIntoDom(signal);
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 signal.value = 'new signal value';
                 await Promise.resolve();
                 expect(elm.shadowRoot.textContent).toBe('new signal value');
@@ -49,13 +51,13 @@ describe('signal reaction in lwc', () => {
                 const elm = await createElementSignalAndInsertIntoDom({
                     value: 'non signal value',
                 });
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 expect(elm.shadowRoot.textContent).toBe('non signal value');
             });
             it('will not warn if rendering signal objects', async () => {
                 const signal = new Signal('signal value');
                 const elm = await createElementSignalAndInsertIntoDom(signal);
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 signal.value = 'new signal value';
                 await Promise.resolve();
                 expect(elm.shadowRoot.textContent).toBe('new signal value');
@@ -80,15 +82,20 @@ describe('signal reaction in lwc', () => {
                 const elm = await createElementSignalAndInsertIntoDom({
                     value: 'non signal value',
                 });
-                expect(consoleSpy.calls.warn[0][0].message).toContain(
-                    'Attempted to subscribe to an object that has the shape of a signal but received the following error: TypeError: signal.subscribe is not a function'
+                expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(expect.any(Error));
+                expect(consoleSpy).toHaveBeenCalledExactlyOnceWith(
+                    expect.objectContaining({
+                        message: expect.stringContaining(
+                            'Attempted to subscribe to an object that has the shape of a signal but received the following error: TypeError: signal.subscribe is not a function'
+                        ),
+                    })
                 );
                 expect(elm.shadowRoot.textContent).toBe('non signal value');
             });
             it('will not warn if rendering signal objects', async () => {
                 const signal = new Signal('signal value');
                 const elm = await createElementSignalAndInsertIntoDom(signal);
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 signal.value = 'new signal value';
                 await Promise.resolve();
                 expect(elm.shadowRoot.textContent).toBe('new signal value');
@@ -103,7 +110,7 @@ describe('signal reaction in lwc', () => {
                 const elm = await createElementSignalAndInsertIntoDom({
                     value: 'non signal value',
                 });
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 expect(elm.shadowRoot.textContent).toBe('non signal value');
             });
             /**
@@ -116,7 +123,7 @@ describe('signal reaction in lwc', () => {
             it('will not warn if rendering signal objects but it will not react', async () => {
                 const signal = new Signal('signal value');
                 const elm = await createElementSignalAndInsertIntoDom(signal);
-                expect(consoleSpy.calls.warn.length).toEqual(0);
+                expect(consoleSpy).not.toHaveBeenCalled();
                 signal.value = 'new signal value';
                 await Promise.resolve();
                 expect(elm.shadowRoot.textContent).toBe('signal value');
diff --git a/packages/@lwc/integration-not-karma/test/template/directive-for-each/index.spec.js b/packages/@lwc/integration-not-karma/test/template/directive-for-each/index.spec.js
index 3dee1e468e..e40480d39f 100644
--- a/packages/@lwc/integration-not-karma/test/template/directive-for-each/index.spec.js
+++ b/packages/@lwc/integration-not-karma/test/template/directive-for-each/index.spec.js
@@ -3,7 +3,7 @@ import XTest from 'x/test';
 import XTestStatic from 'x/testStatic';
 import XTestCustomElement from 'x/testCustomElement';
 import ArrayNullPrototype from 'x/arrayNullPrototype';
-import { spyConsole } from '../../../helpers/console.js';
+import { spyOn } from '@vitest/spy';
 
 function testForEach(type, obj) {
     it(`should render ${type}`, () => {
@@ -73,14 +73,10 @@ it('should throw an error when the passing a non iterable', () => {
 
 describe('null/undefined values', () => {
     let spy;
-
     beforeEach(() => {
-        spy = spyConsole();
-    });
-
-    afterEach(() => {
-        spy.reset();
+        spy = spyOn(console, 'error').mockImplementation(() => {});
     });
+    afterEach(() => spy.mockRestore());
 
     [undefined, null].forEach((value) => {
         it(`should log an error when passing in ${value}`, async () => {
@@ -93,13 +89,16 @@ describe('null/undefined values', () => {
             expect(elm.shadowRoot.querySelector('ul').children.length).toBe(0);
 
             if (process.env.NODE_ENV === 'production') {
-                expect(spy.calls.error.length).toBe(0);
+                expect(spy).not.toHaveBeenCalled();
             } else {
-                expect(spy.calls.error.length).toBe(1);
-                const err = spy.calls.error[0][0]; // first arg of first call
-                expect(err).toBeInstanceOf(Error);
-                // TODO [#1283]: Improve this error message. The vm should not be exposed and the message is not helpful.
-                expect(err.message).toMatch(/It must be an array-like object/);
+                expect(spy).toHaveBeenCalledTimes(1);
+                expect(spy).toHaveBeenCalledWith(expect.any(Error));
+                expect(spy).toHaveBeenCalledWith(
+                    expect.objectContaining({
+                        // TODO [#1283]: Improve this error message. The vm should not be exposed and the message is not helpful.
+                        message: expect.stringMatching(/It must be an array-like object/),
+                    })
+                );
             }
         });
     });