diff --git a/src/test/java/io/r2dbc/pool/ConnectionPoolUnitTests.java b/src/test/java/io/r2dbc/pool/ConnectionPoolUnitTests.java
index 1c29471..8d26d44 100644
--- a/src/test/java/io/r2dbc/pool/ConnectionPoolUnitTests.java
+++ b/src/test/java/io/r2dbc/pool/ConnectionPoolUnitTests.java
@@ -32,6 +32,7 @@
 import org.springframework.util.ReflectionUtils;
 import reactor.core.Disposable;
 import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
 import reactor.test.StepVerifier;
 
 import javax.management.MBeanServer;
@@ -143,7 +144,7 @@ void shouldConsiderInitialSize() {
         when(connectionFactoryMock.create()).thenReturn((Publisher) Mono.just(connectionMock).doOnNext(it -> creations.incrementAndGet()));
         when(connectionMock.validate(any())).thenReturn(Mono.empty());
 
-        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).build();
+        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).allocatorSubscribeOn(Schedulers.immediate()).build();
         ConnectionPool pool = new ConnectionPool(configuration);
 
         pool.create().as(StepVerifier::create).consumeNextWith(actual -> {
@@ -188,7 +189,7 @@ void shouldConsiderCustomizer() {
         when(connectionFactoryMock.create()).thenReturn((Publisher) Mono.just(connectionMock).doOnNext(it -> creations.incrementAndGet()));
         when(connectionMock.validate(any())).thenReturn(Mono.empty());
 
-        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).customizer(connectionPoolBuilder -> connectionPoolBuilder.sizeBetween(2, 10)).build();
+        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).allocatorSubscribeOn(Schedulers.immediate()).customizer(connectionPoolBuilder -> connectionPoolBuilder.sizeBetween(2, 10)).build();
         ConnectionPool pool = new ConnectionPool(configuration);
 
         pool.create().as(StepVerifier::create).consumeNextWith(actual -> {
@@ -212,7 +213,7 @@ void shouldReusePooledConnection() {
         AtomicLong createCounter = new AtomicLong();
         when(connectionFactoryMock.create()).thenReturn((Publisher) Mono.just(connectionMock).doOnSubscribe(ignore -> createCounter.incrementAndGet()));
 
-        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).initialSize(0).build();
+        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).allocatorSubscribeOn(Schedulers.immediate()).initialSize(0).build();
         ConnectionPool pool = new ConnectionPool(configuration);
 
         pool.create().as(StepVerifier::create).assertNext(actual -> {
@@ -237,7 +238,7 @@ void shouldCreateMultipleConnections() {
         when(connectionFactoryMock.create()).thenReturn((Publisher) Mono.just(connectionMock).doOnSubscribe(ignore -> createCounter.incrementAndGet()));
         when(connectionMock.validate(any())).thenReturn(Mono.empty());
 
-        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).initialSize(0).build();
+        ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock).allocatorSubscribeOn(Schedulers.immediate()).initialSize(0).build();
         ConnectionPool pool = new ConnectionPool(configuration);
 
         pool.create().as(StepVerifier::create).expectNextCount(1).verifyComplete();
@@ -411,6 +412,7 @@ void shouldReusePooledConnectionAfterTimeout() {
         when(connectionFactoryMock.create()).thenReturn((Publisher) connectionPublisher);
 
         ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock)
+            .allocatorSubscribeOn(Schedulers.immediate())
             .acquireRetry(0)
             .initialSize(0)
             .maxAcquireTime(Duration.ofMillis(70))
@@ -850,6 +852,7 @@ void shouldDropConnectionOnFailedValidation() {
         when(connectionMock.validate(ValidationDepth.LOCAL)).thenReturn(Mono.just(false), Mono.empty());
 
         ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock)
+            .allocatorSubscribeOn(Schedulers.immediate())
             .acquireRetry(0)
             .initialSize(0)
             .maxSize(2)
@@ -876,6 +879,7 @@ void shouldDropConnectionOnFailedValidationWithRetry() {
         when(connectionMock.validate(ValidationDepth.LOCAL)).thenReturn(Mono.just(false), Mono.just(false), Mono.empty());
 
         ConnectionPoolConfiguration configuration = ConnectionPoolConfiguration.builder(connectionFactoryMock)
+            .allocatorSubscribeOn(Schedulers.immediate())
             .acquireRetry(1)
             .initialSize(0)
             .maxSize(2)