diff --git a/packages/sds/src/message_channel/message_channel.spec.ts b/packages/sds/src/message_channel/message_channel.spec.ts
index ea1629250c..2ba2758452 100644
--- a/packages/sds/src/message_channel/message_channel.spec.ts
+++ b/packages/sds/src/message_channel/message_channel.spec.ts
@@ -4,6 +4,7 @@ import { expect } from "chai";
 import { DefaultBloomFilter } from "../bloom_filter/bloom.js";
 
 import { MessageChannelEvent } from "./events.js";
+import { MemLocalHistory } from "./mem_local_history.js";
 import {
   ContentMessage,
   HistoryEntry,
@@ -22,6 +23,28 @@ const callback = (_message: Message): Promise<{ success: boolean }> => {
   return Promise.resolve({ success: true });
 };
 
+/**
+ * Test helper to create a MessageChannel with MemLocalHistory.
+ * This avoids localStorage pollution in tests and tests core functionality.
+ */
+const createTestChannel = (
+  channelId: string,
+  senderId: string,
+  options: {
+    causalHistorySize?: number;
+    possibleAcksThreshold?: number;
+    timeoutForLostMessagesMs?: number;
+    enableRepair?: boolean;
+  } = {}
+): MessageChannel => {
+  return new MessageChannel(
+    channelId,
+    senderId,
+    options,
+    new MemLocalHistory()
+  );
+};
+
 const getBloomFilter = (channel: MessageChannel): DefaultBloomFilter => {
   return channel["filter"] as DefaultBloomFilter;
 };
@@ -68,7 +91,7 @@ describe("MessageChannel", function () {
 
   describe("sending a message ", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice");
+      channelA = createTestChannel(channelId, "alice");
     });
 
     it("should increase lamport timestamp", async () => {
@@ -171,8 +194,8 @@ describe("MessageChannel", function () {
 
   describe("receiving a message", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice");
-      channelB = new MessageChannel(channelId, "bob");
+      channelA = createTestChannel(channelId, "alice");
+      channelB = createTestChannel(channelId, "bob");
     });
 
     it("should increase lamport timestamp", async () => {
@@ -187,8 +210,8 @@ describe("MessageChannel", function () {
 
     // TODO: test is failing in CI, investigate in https://github.com/waku-org/js-waku/issues/2648
     it.skip("should update lamport timestamp if greater than current timestamp and dependencies are met", async () => {
-      const testChannelA = new MessageChannel(channelId, "alice");
-      const testChannelB = new MessageChannel(channelId, "bob");
+      const testChannelA = createTestChannel(channelId, "alice");
+      const testChannelB = createTestChannel(channelId, "bob");
 
       const timestampBefore = testChannelA["lamportTimestamp"];
 
@@ -452,10 +475,10 @@ describe("MessageChannel", function () {
 
   describe("reviewing ack status", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice", {
+      channelA = createTestChannel(channelId, "alice", {
         causalHistorySize: 2
       });
-      channelB = new MessageChannel(channelId, "bob", { causalHistorySize: 2 });
+      channelB = createTestChannel(channelId, "bob", { causalHistorySize: 2 });
     });
 
     it("should mark all messages in causal history as acknowledged", async () => {
@@ -661,10 +684,10 @@ describe("MessageChannel", function () {
 
   describe("Sweeping incoming buffer", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice", {
+      channelA = createTestChannel(channelId, "alice", {
         causalHistorySize: 2
       });
-      channelB = new MessageChannel(channelId, "bob", { causalHistorySize: 2 });
+      channelB = createTestChannel(channelId, "bob", { causalHistorySize: 2 });
     });
 
     it("should detect messages with missing dependencies", async () => {
@@ -746,7 +769,7 @@ describe("MessageChannel", function () {
 
     it("should mark a message as irretrievably lost if timeout is exceeded", async () => {
       // Create a channel with very very short timeout
-      const channelC: MessageChannel = new MessageChannel(channelId, "carol", {
+      const channelC = createTestChannel(channelId, "carol", {
         timeoutForLostMessagesMs: 10
       });
 
@@ -789,7 +812,7 @@ describe("MessageChannel", function () {
       let lostMessages: HistoryEntry[] = [];
 
       // Create a channel with very short timeout
-      const channelC: MessageChannel = new MessageChannel(channelId, "carol", {
+      const channelC = createTestChannel(channelId, "carol", {
         timeoutForLostMessagesMs: 10
       });
 
@@ -853,7 +876,7 @@ describe("MessageChannel", function () {
     it("should remove messages without delivering if timeout is exceeded", async () => {
       const causalHistorySize = channelA["causalHistorySize"];
       // Create a channel with very very short timeout
-      const channelC: MessageChannel = new MessageChannel(channelId, "carol", {
+      const channelC = createTestChannel(channelId, "carol", {
         timeoutForLostMessagesMs: 10
       });
 
@@ -1043,10 +1066,10 @@ describe("MessageChannel", function () {
 
   describe("Sweeping outgoing buffer", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice", {
+      channelA = createTestChannel(channelId, "alice", {
         causalHistorySize: 2
       });
-      channelB = new MessageChannel(channelId, "bob", { causalHistorySize: 2 });
+      channelB = createTestChannel(channelId, "bob", { causalHistorySize: 2 });
     });
 
     it("should partition messages based on acknowledgement status", async () => {
@@ -1088,10 +1111,10 @@ describe("MessageChannel", function () {
 
   describe("Sync messages", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice", {
+      channelA = createTestChannel(channelId, "alice", {
         causalHistorySize: 2
       });
-      channelB = new MessageChannel(channelId, "bob", { causalHistorySize: 2 });
+      channelB = createTestChannel(channelId, "bob", { causalHistorySize: 2 });
       const message = utf8ToBytes("first message in channel");
       channelA["localHistory"].push(
         new ContentMessage(
@@ -1115,7 +1138,7 @@ describe("MessageChannel", function () {
     });
 
     it("should not be sent when there is no history", async () => {
-      const channelC = new MessageChannel(channelId, "carol", {
+      const channelC = createTestChannel(channelId, "carol", {
         causalHistorySize: 2
       });
       const res = await channelC.pushOutgoingSyncMessage(async (_msg) => {
@@ -1160,7 +1183,7 @@ describe("MessageChannel", function () {
     });
 
     it("should update ack status of messages in outgoing buffer", async () => {
-      const channelC = new MessageChannel(channelId, "carol", {
+      const channelC = createTestChannel(channelId, "carol", {
         causalHistorySize: 2
       });
       for (const m of messagesA) {
@@ -1185,7 +1208,7 @@ describe("MessageChannel", function () {
 
   describe("Ephemeral messages", () => {
     beforeEach(() => {
-      channelA = new MessageChannel(channelId, "alice");
+      channelA = createTestChannel(channelId, "alice");
     });
 
     it("should be sent without a timestamp, causal history, or bloom filter", async () => {
@@ -1208,7 +1231,7 @@ describe("MessageChannel", function () {
     });
 
     it("should be delivered immediately if received", async () => {
-      const channelB = new MessageChannel(channelId, "bob");
+      const channelB = createTestChannel(channelId, "bob");
 
       // Track initial state
       const localHistoryBefore = channelB["localHistory"].length;