diff --git a/src/test/java/io/netty/buffer/api/BufferTest.java b/src/test/java/io/netty/buffer/api/BufferTest.java
index b10e262..e218f0a 100644
--- a/src/test/java/io/netty/buffer/api/BufferTest.java
+++ b/src/test/java/io/netty/buffer/api/BufferTest.java
@@ -59,15 +59,43 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.junit.jupiter.api.Assertions.fail;
 
 public class BufferTest {
-    private static volatile Fixture[] fixtures;
     private static ExecutorService executor;
 
+    private static final Memoize<Fixture[]> ALL_COMBINATIONS = new Memoize<>(
+            () -> fixtureCombinations().toArray(Fixture[]::new));
+    private static final Memoize<Fixture[]> NON_SLICED = new Memoize<>(
+            () -> Arrays.stream(ALL_COMBINATIONS.get()).filter(f -> !f.isSlice()).toArray(Fixture[]::new));
+    private static final Memoize<Fixture[]> NON_COMPOSITE = new Memoize<>(
+            () -> Arrays.stream(ALL_COMBINATIONS.get()).filter(f -> !f.isComposite()).toArray(Fixture[]::new));
+    private static final Memoize<Fixture[]> HEAP_ALLOCS = new Memoize<>(
+            () -> Arrays.stream(ALL_COMBINATIONS.get()).filter(f -> f.isHeap()).toArray(Fixture[]::new));
+    private static final Memoize<Fixture[]> DIRECT_ALLOCS = new Memoize<>(
+            () -> Arrays.stream(ALL_COMBINATIONS.get()).filter(f -> f.isDirect()).toArray(Fixture[]::new));
+    private static final Memoize<Fixture[]> POOLED_ALLOCS = new Memoize<>(
+            () -> Arrays.stream(ALL_COMBINATIONS.get()).filter(f -> f.isPooled()).toArray(Fixture[]::new));
+
     static Fixture[] allocators() {
-        Fixture[] fxs = fixtures;
-        if (fxs != null) {
-            return fxs;
-        }
-        return fixtures = fixtureCombinations().toArray(Fixture[]::new);
+        return ALL_COMBINATIONS.get();
+    }
+
+    static Fixture[] nonSliceAllocators() {
+        return NON_SLICED.get();
+    }
+
+    static Fixture[] nonCompositeAllocators() {
+        return NON_COMPOSITE.get();
+    }
+
+    static Fixture[] heapAllocators() {
+        return HEAP_ALLOCS.get();
+    }
+
+    static Fixture[] directAllocators() {
+        return DIRECT_ALLOCS.get();
+    }
+
+    static Fixture[] pooledAllocators() {
+        return POOLED_ALLOCS.get();
     }
 
     static List<Fixture> initialAllocators() {
@@ -78,35 +106,7 @@ public class BufferTest {
                 new Fixture("pooledDirect", BufferAllocator::pooledDirect, POOLED, DIRECT, CLEANER));
     }
 
-    static Stream<Fixture> nonSliceAllocators() {
-        return fixtureCombinations().filter(f -> !f.isSlice());
-    }
-
-    static Stream<Fixture> nonCompositeAllocators() {
-        return fixtureCombinations().filter(f -> !f.isComposite());
-    }
-
-    static Stream<Fixture> heapAllocators() {
-        return fixtureCombinations().filter(Fixture::isHeap);
-    }
-
-    static Stream<Fixture> directAllocators() {
-        return fixtureCombinations().filter(Fixture::isDirect);
-    }
-
-    static Stream<Fixture> directPooledAllocators() {
-        return fixtureCombinations().filter(f -> f.isDirect() && f.isCleaner() && f.isPooled());
-    }
-
-    static Stream<Fixture> pooledAllocators() {
-        return fixtureCombinations().filter(Fixture::isPooled);
-    }
-
     private static Stream<Fixture> fixtureCombinations() {
-        Fixture[] fxs = fixtures;
-        if (fxs != null) {
-            return Arrays.stream(fxs);
-        }
         List<Fixture> initFixtures = initialAllocators();
         Builder<Fixture> builder = Stream.builder();
         initFixtures.forEach(builder);
diff --git a/src/test/java/io/netty/buffer/api/Memoize.java b/src/test/java/io/netty/buffer/api/Memoize.java
new file mode 100644
index 0000000..bc5db8d
--- /dev/null
+++ b/src/test/java/io/netty/buffer/api/Memoize.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2021 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.buffer.api;
+
+import java.util.function.Supplier;
+
+final class Memoize<T> implements Supplier<T> {
+    private final Supplier<T> supplier;
+    private volatile T memo;
+
+    Memoize(Supplier<T> supplier) {
+        this.supplier = supplier;
+    }
+
+    @Override
+    public T get() {
+        T val = memo;
+        if (val == null) {
+            memo = val = supplier.get();
+        }
+        return val;
+    }
+}
diff --git a/src/test/resources/junit-platform.properties b/src/test/resources/junit-platform.properties
new file mode 100644
index 0000000..080b321
--- /dev/null
+++ b/src/test/resources/junit-platform.properties
@@ -0,0 +1,18 @@
+# Copyright 2021 The Netty Project
+#
+# The Netty Project licenses this file to you under the Apache License,
+# version 2.0 (the "License"); you may not use this file except in compliance
+# with the License. You may obtain a copy of the License at:
+#
+#   https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+junit.jupiter.execution.parallel.enabled = true
+junit.jupiter.execution.parallel.mode.default = concurrent
+junit.jupiter.testinstance.lifecycle.default = per_class
+junit.jupiter.execution.parallel.config.strategy = fixed
+junit.jupiter.execution.parallel.config.fixed.parallelism = 16