diff --git a/.config/vite-utils/polyfills.ts b/.config/vite-utils/polyfills.ts
index f020ab89..35cd70f3 100644
--- a/.config/vite-utils/polyfills.ts
+++ b/.config/vite-utils/polyfills.ts
@@ -54,6 +54,8 @@ export function setupChai(chai: any, vitestExpect: any) {
         writable: true,
         configurable: true,
     })
+
+    chai.expect.addEqualityTesters = customTesters => vitestExpect.addCustomEqualityTesters(customTesters)
 }
 
 const stubbedGlobal = new Map()
diff --git a/.config/vite-utils/test-setup.mts b/.config/vite-utils/test-setup.mts
index c402f362..1be216bc 100644
--- a/.config/vite-utils/test-setup.mts
+++ b/.config/vite-utils/test-setup.mts
@@ -1,8 +1,19 @@
+import { expect } from 'vitest'
 import { setPlatform } from '../../packages/core/src/platform.js'
+import { buffersEqual } from '../../packages/core/src/utils/buffer-utils.js'
 
 // @ts-expect-error no .env here
 if (import.meta.env.TEST_ENV === 'browser' || import.meta.env.TEST_ENV === 'deno') {
     setPlatform(new (await import('../../packages/web/src/platform.js')).WebPlatform())
 } else {
     setPlatform(new (await import('../../packages/node/src/common-internals-node/platform.js')).NodePlatform())
-}
\ No newline at end of file
+}
+
+// consider Buffers equal to Uint8Arrays
+expect.addEqualityTesters([
+    function (a, b) {
+        if (a instanceof Uint8Array && b instanceof Uint8Array) {
+            return buffersEqual(a, b)
+        }
+    }
+])
\ No newline at end of file
diff --git a/packages/test/src/crypto.ts b/packages/test/src/crypto.ts
index 99d52c80..42d91799 100644
--- a/packages/test/src/crypto.ts
+++ b/packages/test/src/crypto.ts
@@ -1,5 +1,5 @@
 import { gzipSync, inflateSync } from 'node:zlib'
-import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from 'vitest'
+import { afterEach, beforeAll, beforeEach, describe, expect, it, MockInstance, vi } from 'vitest'
 
 import { getPlatform } from '@mtcute/core/platform.js'
 import { dataViewFromBuffer, ICryptoProvider } from '@mtcute/core/utils.js'
@@ -53,10 +53,12 @@ export function useFakeMathRandom(source = DEFAULT_ENTROPY): void {
     const sourceBytes = getPlatform().hexDecode(source)
     const dv = dataViewFromBuffer(sourceBytes)
 
+    let spy: MockInstance<[], number>
+
     beforeEach(() => {
         let offset = 0
 
-        vi.spyOn(globalThis.Math, 'random').mockImplementation(() => {
+        spy = vi.spyOn(globalThis.Math, 'random').mockImplementation(() => {
             const ret = dv.getUint32(offset, true) / 0xffffffff
             offset += 4
 
@@ -64,7 +66,7 @@ export function useFakeMathRandom(source = DEFAULT_ENTROPY): void {
         })
     })
     afterEach(() => {
-        vi.spyOn(globalThis.Math, 'random').mockRestore()
+        spy.mockRestore()
     })
 }