diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 4c9612ad08..4fca0988f8 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -19,9 +19,10 @@ To help ensure your PR passes, just run before committing:
 
 To build and test this repository, you need:
   
-  - [Node.js & npm](https://nodejs.org/en/)
-  - [bufbuild](https://github.com/bufbuild/buf) (only if changing protobuf files)
-  - [protoc](https://grpc.io/docs/protoc-installation/) (only if changing protobuf files)
+  - [Node.js & npm](https://nodejs.org/en/).
+  - [bufbuild](https://github.com/bufbuild/buf) (only if changing protobuf files).
+  - [protoc](https://grpc.io/docs/protoc-installation/) (only if changing protobuf files).
+  - Firefox & Chrome (for browser testing).
 
 To ensure interoperability with [nim-waku](https://github.com/status-im/nim-waku/), some tests are run against a nim-waku node.
 This is why `nim-waku` is present as a [git submodule](https://git-scm.com/book/en/v2/Git-Tools-Submodules), which itself contain several submodules.
@@ -29,10 +30,14 @@ At this stage, it is not possible to exclude nim-waku tests, hence `git submodul
 
 To build nim-waku, you also need [Rust](https://www.rust-lang.org/tools/install).
 
+Note that we run tests in both NodeJS and browser environments (both Chrome and Firefox, using [karma](https://karma-runner.github.io/)).
+Files named `*.spec.ts` are only run in NodeJS environment;
+Files named `*.browser.spec.ts` are run in both NodeJS and browser environment.
+
 ## Guidelines
 
-- Please follow [Chris Beam's commit message guide](https://chris.beams.io/posts/git-commit/),
-- Usually best to test new code,
+- Please follow [Chris Beam's commit message guide](https://chris.beams.io/posts/git-commit/) for commit patches,
+- Please test new code, we use [mocha](https://mochajs.org/), [chai](https://www.chaijs.com/) and [karma](https://karma-runner.github.io/).
 
 ### Committing Patches
 
diff --git a/karma.conf.js b/karma.conf.js
index 35a9e1ff2b..f0b71c49a1 100644
--- a/karma.conf.js
+++ b/karma.conf.js
@@ -3,11 +3,7 @@ process.env.CHROME_BIN = require('puppeteer').executablePath();
 module.exports = function (config) {
   config.set({
     frameworks: ['mocha', 'karma-typescript'],
-    files: [
-      'src/lib/**/*.ts',
-      'src/proto/**/*.ts',
-      'src/tests/browser/*.spec.ts',
-    ],
+    files: ['src/lib/**/*.ts', 'src/proto/**/*.ts'],
     preprocessors: {
       '**/*.ts': ['karma-typescript'],
     },
@@ -21,7 +17,7 @@ module.exports = function (config) {
     singleRun: true,
     karmaTypescriptConfig: {
       bundlerOptions: {
-        entrypoints: /src\/tests\/browser\/.*\.spec\.ts$/,
+        entrypoints: /.*\.browser\.spec\.ts$/,
       },
       tsconfig: './tsconfig.karma.json',
       coverageOptions: {
diff --git a/src/tests/browser/waku_message.spec.ts b/src/lib/waku_message/index.browser.spec.ts
similarity index 95%
rename from src/tests/browser/waku_message.spec.ts
rename to src/lib/waku_message/index.browser.spec.ts
index 8657354b3e..d167e539c9 100644
--- a/src/tests/browser/waku_message.spec.ts
+++ b/src/lib/waku_message/index.browser.spec.ts
@@ -1,12 +1,6 @@
 import { expect } from 'chai';
 import fc from 'fast-check';
 
-fc.configureGlobal({
-  interruptAfterTimeLimit: 1500,
-  markInterruptAsFailure: true,
-  numRuns: 10, // Firefox is too slow for 100 (fc default) runs in 2s (mocha default)
-});
-
 import { WakuMessage } from '../../lib/waku_message';
 import { getPublicKey } from '../../lib/waku_message/version_1';
 
diff --git a/src/lib/waku_message/version_1.spec.ts b/src/lib/waku_message/version_1.browser.spec.ts
similarity index 100%
rename from src/lib/waku_message/version_1.spec.ts
rename to src/lib/waku_message/version_1.browser.spec.ts
diff --git a/src/tests/browser/version_1.spec.ts b/src/tests/browser/version_1.spec.ts
deleted file mode 100644
index 8721e40d74..0000000000
--- a/src/tests/browser/version_1.spec.ts
+++ /dev/null
@@ -1,74 +0,0 @@
-import { expect } from 'chai';
-import fc from 'fast-check';
-
-import {
-  clearDecode,
-  clearEncode,
-  decryptAsymmetric,
-  decryptSymmetric,
-  encryptAsymmetric,
-  encryptSymmetric,
-  getPublicKey,
-} from '../../lib/waku_message/version_1';
-
-describe('Waku Message Version 1', function () {
-  it('Sign & Recover', function () {
-    fc.assert(
-      fc.property(
-        fc.uint8Array(),
-        fc.uint8Array({ minLength: 32, maxLength: 32 }),
-        (message, privKey) => {
-          const enc = clearEncode(message, privKey);
-          const res = clearDecode(enc.payload);
-
-          const pubKey = getPublicKey(privKey);
-
-          expect(res?.payload).deep.equal(
-            message,
-            'Payload was not encrypted then decrypted correctly'
-          );
-          expect(res?.sig?.publicKey).deep.equal(
-            pubKey,
-            'signature Public key was not recovered from encrypted then decrypted signature'
-          );
-          expect(enc?.sig?.publicKey).deep.equal(
-            pubKey,
-            'Incorrect signature public key was returned when signing the payload'
-          );
-        }
-      )
-    );
-  });
-
-  it('Asymmetric encrypt & Decrypt', async function () {
-    await fc.assert(
-      fc.asyncProperty(
-        fc.uint8Array({ minLength: 1 }),
-        fc.uint8Array({ minLength: 32, maxLength: 32 }),
-        async (message, privKey) => {
-          const publicKey = getPublicKey(privKey);
-
-          const enc = await encryptAsymmetric(message, publicKey);
-          const res = await decryptAsymmetric(enc, privKey);
-
-          expect(res).deep.equal(message);
-        }
-      )
-    );
-  });
-
-  it('Symmetric encrypt & Decrypt', async function () {
-    await fc.assert(
-      fc.asyncProperty(
-        fc.uint8Array(),
-        fc.uint8Array({ minLength: 32, maxLength: 32 }),
-        async (message, key) => {
-          const enc = await encryptSymmetric(message, key);
-          const res = await decryptSymmetric(enc, key);
-
-          expect(res).deep.equal(message);
-        }
-      )
-    );
-  });
-});