diff --git a/tavern/internal/http/stream/gcp_coldstart_test.go b/tavern/internal/http/stream/gcp_coldstart_test.go
index 45722466e..acfc3eb88 100644
--- a/tavern/internal/http/stream/gcp_coldstart_test.go
+++ b/tavern/internal/http/stream/gcp_coldstart_test.go
@@ -2,6 +2,7 @@ package stream_test
 
 import (
 	"context"
+	"fmt"
 	"testing"
 	"time"
 
@@ -16,18 +17,19 @@ func TestPreventPubSubColdStarts_ValidInterval(t *testing.T) {
 	defer cancel()
 
 	// Create a mock topic and subscription.
-	topic, err := pubsub.OpenTopic(ctx, "mem://valid")
+	topicName := fmt.Sprintf("mem://valid-%d", time.Now().UnixNano())
+	topic, err := pubsub.OpenTopic(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open topic: %v", err)
 	}
 	defer topic.Shutdown(ctx)
-	sub, err := pubsub.OpenSubscription(ctx, "mem://valid")
+	sub, err := pubsub.OpenSubscription(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open subscription: %v", err)
 	}
 	defer sub.Shutdown(ctx)
 
-	go stream.PreventPubSubColdStarts(ctx, 50*time.Millisecond, "mem://valid", "mem://valid")
+	go stream.PreventPubSubColdStarts(ctx, 50*time.Millisecond, topicName, topicName)
 
 	// Expect to receive a message
 	msg, err := sub.Receive(ctx)
@@ -43,18 +45,19 @@ func TestPreventPubSubColdStarts_ZeroInterval(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 	defer cancel()
 
-	topic, err := pubsub.OpenTopic(ctx, "mem://zero")
+	topicName := fmt.Sprintf("mem://zero-%d", time.Now().UnixNano())
+	topic, err := pubsub.OpenTopic(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open topic: %v", err)
 	}
 	defer topic.Shutdown(ctx)
-	sub, err := pubsub.OpenSubscription(ctx, "mem://zero")
+	sub, err := pubsub.OpenSubscription(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open subscription: %v", err)
 	}
 	defer sub.Shutdown(ctx)
 
-	go stream.PreventPubSubColdStarts(ctx, 0, "mem://zero", "mem://zero")
+	go stream.PreventPubSubColdStarts(ctx, 0, topicName, topicName)
 
 	// Expect to not receive a message and for the context to timeout
 	_, err = sub.Receive(ctx)
@@ -66,18 +69,19 @@ func TestPreventPubSubColdStarts_SubMillisecondInterval(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
 	defer cancel()
 
-	topic, err := pubsub.OpenTopic(ctx, "mem://sub")
+	topicName := fmt.Sprintf("mem://sub-%d", time.Now().UnixNano())
+	topic, err := pubsub.OpenTopic(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open topic: %v", err)
 	}
 	defer topic.Shutdown(ctx)
-	sub, err := pubsub.OpenSubscription(ctx, "mem://sub")
+	sub, err := pubsub.OpenSubscription(ctx, topicName)
 	if err != nil {
 		t.Fatalf("Failed to open subscription: %v", err)
 	}
 	defer sub.Shutdown(ctx)
 
-	go stream.PreventPubSubColdStarts(ctx, 1*time.Microsecond, "mem://sub", "mem://sub")
+	go stream.PreventPubSubColdStarts(ctx, 1*time.Microsecond, topicName, topicName)
 
 	// Expect to receive a message
 	msg, err := sub.Receive(ctx)
diff --git a/tavern/internal/http/stream/mux_test.go b/tavern/internal/http/stream/mux_test.go
index 38be5b97a..de466ed4f 100644
--- a/tavern/internal/http/stream/mux_test.go
+++ b/tavern/internal/http/stream/mux_test.go
@@ -2,6 +2,7 @@ package stream_test
 
 import (
 	"context"
+	"fmt"
 	"testing"
 	"time"
 
@@ -17,10 +18,11 @@ func TestMux(t *testing.T) {
 	defer cancel()
 
 	// Setup Topic and Subscription
-	topic, err := pubsub.OpenTopic(ctx, "mem://mux-test")
+	topicName := fmt.Sprintf("mem://mux-test-%d", time.Now().UnixNano())
+	topic, err := pubsub.OpenTopic(ctx, topicName)
 	require.NoError(t, err)
 	defer topic.Shutdown(ctx)
-	sub, err := pubsub.OpenSubscription(ctx, "mem://mux-test")
+	sub, err := pubsub.OpenSubscription(ctx, topicName)
 	require.NoError(t, err)
 	defer sub.Shutdown(ctx)
 
@@ -37,9 +39,6 @@ func TestMux(t *testing.T) {
 	mux.Register(stream2)
 	defer mux.Unregister(stream2)
 
-	// Give the mux a moment to register the streams
-	time.Sleep(50 * time.Millisecond)
-
 	// Send a message for stream1
 	err = topic.Send(ctx, &pubsub.Message{
 		Body:     []byte("hello stream 1"),
diff --git a/tavern/internal/http/stream/stream_test.go b/tavern/internal/http/stream/stream_test.go
index 7a837e0ee..3d6fb02cd 100644
--- a/tavern/internal/http/stream/stream_test.go
+++ b/tavern/internal/http/stream/stream_test.go
@@ -17,10 +17,11 @@ func TestStream_SendMessage(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	topic, err := pubsub.OpenTopic(ctx, "mem://stream-test-send")
+	topicName := fmt.Sprintf("mem://stream-test-send-%d", time.Now().UnixNano())
+	topic, err := pubsub.OpenTopic(ctx, topicName)
 	require.NoError(t, err)
 	defer topic.Shutdown(ctx)
-	sub, err := pubsub.OpenSubscription(ctx, "mem://stream-test-send")
+	sub, err := pubsub.OpenSubscription(ctx, topicName)
 	require.NoError(t, err)
 	defer sub.Shutdown(ctx)
 
diff --git a/tavern/internal/http/stream/websocket_test.go b/tavern/internal/http/stream/websocket_test.go
index 8e67d5421..d3cc7770f 100644
--- a/tavern/internal/http/stream/websocket_test.go
+++ b/tavern/internal/http/stream/websocket_test.go
@@ -2,6 +2,7 @@ package stream_test
 
 import (
 	"context"
+	"fmt"
 	"net/http/httptest"
 	"strconv"
 	"strings"
@@ -29,18 +30,20 @@ func TestNewShellHandler(t *testing.T) {
 	defer cancel()
 
 	// Topic for messages going TO the websocket (server -> shell)
-	outputTopic, err := pubsub.OpenTopic(ctx, "mem://websocket-output")
+	outputTopicName := fmt.Sprintf("mem://websocket-output-%d", time.Now().UnixNano())
+	outputTopic, err := pubsub.OpenTopic(ctx, outputTopicName)
 	require.NoError(t, err)
 	defer outputTopic.Shutdown(ctx)
-	outputSub, err := pubsub.OpenSubscription(ctx, "mem://websocket-output")
+	outputSub, err := pubsub.OpenSubscription(ctx, outputTopicName)
 	require.NoError(t, err)
 	defer outputSub.Shutdown(ctx)
 
 	// Topic for messages coming FROM the websocket (shell -> server)
-	inputTopic, err := pubsub.OpenTopic(ctx, "mem://websocket-input")
+	inputTopicName := fmt.Sprintf("mem://websocket-input-%d", time.Now().UnixNano())
+	inputTopic, err := pubsub.OpenTopic(ctx, inputTopicName)
 	require.NoError(t, err)
 	defer inputTopic.Shutdown(ctx)
-	inputSub, err := pubsub.OpenSubscription(ctx, "mem://websocket-input")
+	inputSub, err := pubsub.OpenSubscription(ctx, inputTopicName)
 	require.NoError(t, err)
 	defer inputSub.Shutdown(ctx)
 
diff --git a/tavern/internal/redirectors/grpc/grpc_test.go b/tavern/internal/redirectors/grpc/grpc_test.go
index 5cc768189..6eb690d6c 100644
--- a/tavern/internal/redirectors/grpc/grpc_test.go
+++ b/tavern/internal/redirectors/grpc/grpc_test.go
@@ -155,8 +155,8 @@ func TestRedirector_ContextCancellation(t *testing.T) {
 		serverErr <- redirector.Redirect(ctx, addr, upstreamConn)
 	}()
 
-	// Wait a moment for the server to start listening.
-	time.Sleep(100 * time.Millisecond)
+	// Wait for the server to start listening.
+	waitForServer(t, addr)
 
 	// Cancel the context, which should trigger GracefulStop.
 	cancel()
@@ -215,3 +215,17 @@ func TestRedirector_UpstreamFailure(t *testing.T) {
 	require.True(t, ok, "error should be a gRPC status error")
 	require.Equal(t, codes.Unavailable, s.Code(), "error code should be Unavailable")
 }
+
+func waitForServer(t *testing.T, addr string) {
+	t.Helper()
+	deadline := time.Now().Add(5 * time.Second)
+	for time.Now().Before(deadline) {
+		conn, err := net.DialTimeout("tcp", addr, 100*time.Millisecond)
+		if err == nil {
+			conn.Close()
+			return
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	t.Fatalf("server did not start listening on %s", addr)
+}