diff --git a/examples/contexts/blocking-process.php b/examples/contexts/blocking-process.php
index e72f438..9feb8d1 100644
--- a/examples/contexts/blocking-process.php
+++ b/examples/contexts/blocking-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 // The function returned by this script is run by process.php in a separate process.
 // $argc and $argv are available in this process as any other cli PHP script.
diff --git a/examples/contexts/parcel-process.php b/examples/contexts/parcel-process.php
index a59469d..59b8e29 100644
--- a/examples/contexts/parcel-process.php
+++ b/examples/contexts/parcel-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 // The function returned by this script is run by shared-memory-process.php in a separate process.
 // $argc and $argv are available in this process as any other cli PHP script.
diff --git a/src/Context/Context.php b/src/Context/Context.php
index 51d368a..54bedcf 100644
--- a/src/Context/Context.php
+++ b/src/Context/Context.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/ContextException.php b/src/Context/ContextException.php
index caf4ac3..bb5cab9 100644
--- a/src/Context/ContextException.php
+++ b/src/Context/ContextException.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/ContextFactory.php b/src/Context/ContextFactory.php
index 4b54cbf..b5aabdf 100644
--- a/src/Context/ContextFactory.php
+++ b/src/Context/ContextFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/ContextPanicError.php b/src/Context/ContextPanicError.php
index c6256b2..45aeb3f 100644
--- a/src/Context/ContextPanicError.php
+++ b/src/Context/ContextPanicError.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/DefaultContextFactory.php b/src/Context/DefaultContextFactory.php
index d83a755..1c219ef 100644
--- a/src/Context/DefaultContextFactory.php
+++ b/src/Context/DefaultContextFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/Internal/ContextChannel.php b/src/Context/Internal/ContextChannel.php
index 5cff4df..13264ce 100644
--- a/src/Context/Internal/ContextChannel.php
+++ b/src/Context/Internal/ContextChannel.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/Internal/ContextMessage.php b/src/Context/Internal/ContextMessage.php
index b6f295b..e2b0c67 100644
--- a/src/Context/Internal/ContextMessage.php
+++ b/src/Context/Internal/ContextMessage.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/Internal/ExitFailure.php b/src/Context/Internal/ExitFailure.php
index b88ab93..1b9bdb7 100644
--- a/src/Context/Internal/ExitFailure.php
+++ b/src/Context/Internal/ExitFailure.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/Internal/ExitResult.php b/src/Context/Internal/ExitResult.php
index 477c610..2d3efe9 100644
--- a/src/Context/Internal/ExitResult.php
+++ b/src/Context/Internal/ExitResult.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/Internal/ExitSuccess.php b/src/Context/Internal/ExitSuccess.php
index e1c8973..0f0574c 100644
--- a/src/Context/Internal/ExitSuccess.php
+++ b/src/Context/Internal/ExitSuccess.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/Internal/process-runner.php b/src/Context/Internal/process-runner.php
index b786881..03fb016 100644
--- a/src/Context/Internal/process-runner.php
+++ b/src/Context/Internal/process-runner.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context\Internal;
 
diff --git a/src/Context/ProcessContext.php b/src/Context/ProcessContext.php
index df2c457..de25182 100644
--- a/src/Context/ProcessContext.php
+++ b/src/Context/ProcessContext.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/StatusError.php b/src/Context/StatusError.php
index 97ebba5..f5a28e0 100644
--- a/src/Context/StatusError.php
+++ b/src/Context/StatusError.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Context/functions.php b/src/Context/functions.php
index 0eba14b..1f642d2 100644
--- a/src/Context/functions.php
+++ b/src/Context/functions.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Context;
 
diff --git a/src/Ipc/IpcHub.php b/src/Ipc/IpcHub.php
index 3a77219..acc68be 100644
--- a/src/Ipc/IpcHub.php
+++ b/src/Ipc/IpcHub.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Ipc;
 
diff --git a/src/Ipc/LocalIpcHub.php b/src/Ipc/LocalIpcHub.php
index cf6476c..3f863b6 100644
--- a/src/Ipc/LocalIpcHub.php
+++ b/src/Ipc/LocalIpcHub.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Ipc;
 
diff --git a/src/Ipc/SocketIpcHub.php b/src/Ipc/SocketIpcHub.php
index 3d7d504..fa5adab 100644
--- a/src/Ipc/SocketIpcHub.php
+++ b/src/Ipc/SocketIpcHub.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Ipc;
 
diff --git a/src/Ipc/SynchronizationError.php b/src/Ipc/SynchronizationError.php
index 6a3d7dd..582b0c6 100644
--- a/src/Ipc/SynchronizationError.php
+++ b/src/Ipc/SynchronizationError.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Ipc;
 
diff --git a/src/Ipc/functions.php b/src/Ipc/functions.php
index 8183b3e..d699101 100644
--- a/src/Ipc/functions.php
+++ b/src/Ipc/functions.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Ipc;
 
diff --git a/src/Worker/DefaultWorker.php b/src/Worker/DefaultWorker.php
index 6a5a09c..755b180 100644
--- a/src/Worker/DefaultWorker.php
+++ b/src/Worker/DefaultWorker.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/DefaultWorkerFactory.php b/src/Worker/DefaultWorkerFactory.php
index e4953eb..b196242 100644
--- a/src/Worker/DefaultWorkerFactory.php
+++ b/src/Worker/DefaultWorkerFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/DefaultWorkerPool.php b/src/Worker/DefaultWorkerPool.php
index 9f1d5b5..57f439f 100644
--- a/src/Worker/DefaultWorkerPool.php
+++ b/src/Worker/DefaultWorkerPool.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/Execution.php b/src/Worker/Execution.php
index 9bfe08e..ae93834 100644
--- a/src/Worker/Execution.php
+++ b/src/Worker/Execution.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/Internal/JobCancellation.php b/src/Worker/Internal/JobCancellation.php
index e6eab1b..017f11e 100644
--- a/src/Worker/Internal/JobCancellation.php
+++ b/src/Worker/Internal/JobCancellation.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/JobChannel.php b/src/Worker/Internal/JobChannel.php
index 7ec6e23..5ec91f6 100644
--- a/src/Worker/Internal/JobChannel.php
+++ b/src/Worker/Internal/JobChannel.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/JobMessage.php b/src/Worker/Internal/JobMessage.php
index 3f524fe..c5197ac 100644
--- a/src/Worker/Internal/JobMessage.php
+++ b/src/Worker/Internal/JobMessage.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/JobPacket.php b/src/Worker/Internal/JobPacket.php
index af1081a..ff8f128 100644
--- a/src/Worker/Internal/JobPacket.php
+++ b/src/Worker/Internal/JobPacket.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/PooledWorker.php b/src/Worker/Internal/PooledWorker.php
index 3669842..47ff309 100644
--- a/src/Worker/Internal/PooledWorker.php
+++ b/src/Worker/Internal/PooledWorker.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/TaskCancelled.php b/src/Worker/Internal/TaskCancelled.php
index ffedb06..19772cc 100644
--- a/src/Worker/Internal/TaskCancelled.php
+++ b/src/Worker/Internal/TaskCancelled.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/TaskFailure.php b/src/Worker/Internal/TaskFailure.php
index 9051553..792c9be 100644
--- a/src/Worker/Internal/TaskFailure.php
+++ b/src/Worker/Internal/TaskFailure.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/TaskResult.php b/src/Worker/Internal/TaskResult.php
index b082cfe..7053391 100644
--- a/src/Worker/Internal/TaskResult.php
+++ b/src/Worker/Internal/TaskResult.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/TaskSubmission.php b/src/Worker/Internal/TaskSubmission.php
index 5cce9a3..51ccf16 100644
--- a/src/Worker/Internal/TaskSubmission.php
+++ b/src/Worker/Internal/TaskSubmission.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/TaskSuccess.php b/src/Worker/Internal/TaskSuccess.php
index dbd20b7..3e21544 100644
--- a/src/Worker/Internal/TaskSuccess.php
+++ b/src/Worker/Internal/TaskSuccess.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Internal/task-runner.php b/src/Worker/Internal/task-runner.php
index 78718a6..83965ee 100644
--- a/src/Worker/Internal/task-runner.php
+++ b/src/Worker/Internal/task-runner.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker\Internal;
 
diff --git a/src/Worker/Task.php b/src/Worker/Task.php
index e888060..f8af962 100644
--- a/src/Worker/Task.php
+++ b/src/Worker/Task.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/TaskCancelledException.php b/src/Worker/TaskCancelledException.php
index 21ac5b7..4f4aa21 100644
--- a/src/Worker/TaskCancelledException.php
+++ b/src/Worker/TaskCancelledException.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/TaskFailureError.php b/src/Worker/TaskFailureError.php
index f3688e8..ad0b171 100644
--- a/src/Worker/TaskFailureError.php
+++ b/src/Worker/TaskFailureError.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/TaskFailureException.php b/src/Worker/TaskFailureException.php
index 1b1f982..6e4efd7 100644
--- a/src/Worker/TaskFailureException.php
+++ b/src/Worker/TaskFailureException.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/TaskFailureThrowable.php b/src/Worker/TaskFailureThrowable.php
index e0ab11d..88ef7bb 100644
--- a/src/Worker/TaskFailureThrowable.php
+++ b/src/Worker/TaskFailureThrowable.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/Worker.php b/src/Worker/Worker.php
index b01dee9..26ff3b6 100644
--- a/src/Worker/Worker.php
+++ b/src/Worker/Worker.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/WorkerException.php b/src/Worker/WorkerException.php
index 9f97d15..bcb4bb8 100644
--- a/src/Worker/WorkerException.php
+++ b/src/Worker/WorkerException.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/WorkerFactory.php b/src/Worker/WorkerFactory.php
index 8537774..e9ded41 100644
--- a/src/Worker/WorkerFactory.php
+++ b/src/Worker/WorkerFactory.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/WorkerPool.php b/src/Worker/WorkerPool.php
index 3513d54..0d7f38c 100644
--- a/src/Worker/WorkerPool.php
+++ b/src/Worker/WorkerPool.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/src/Worker/functions.php b/src/Worker/functions.php
index 1e62ac1..a77049a 100644
--- a/src/Worker/functions.php
+++ b/src/Worker/functions.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Worker;
 
diff --git a/test/Context/AbstractContextTest.php b/test/Context/AbstractContextTest.php
index e44c3e2..b46bbdb 100644
--- a/test/Context/AbstractContextTest.php
+++ b/test/Context/AbstractContextTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Context;
 
diff --git a/test/Context/DefaultContextFactoryTest.php b/test/Context/DefaultContextFactoryTest.php
index 414bc79..e08538e 100644
--- a/test/Context/DefaultContextFactoryTest.php
+++ b/test/Context/DefaultContextFactoryTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Context;
 
diff --git a/test/Context/Fixtures/delayed-process.php b/test/Context/Fixtures/delayed-process.php
index 3ac0239..efe5ba0 100644
--- a/test/Context/Fixtures/delayed-process.php
+++ b/test/Context/Fixtures/delayed-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 use function Amp\delay;
diff --git a/test/Context/Fixtures/exiting-process.php b/test/Context/Fixtures/exiting-process.php
index 9731a03..05a2ac4 100644
--- a/test/Context/Fixtures/exiting-process.php
+++ b/test/Context/Fixtures/exiting-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 
diff --git a/test/Context/Fixtures/invalid-result-process.php b/test/Context/Fixtures/invalid-result-process.php
index 3f2398f..6e130e1 100644
--- a/test/Context/Fixtures/invalid-result-process.php
+++ b/test/Context/Fixtures/invalid-result-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 
diff --git a/test/Context/Fixtures/no-callback-process.php b/test/Context/Fixtures/no-callback-process.php
index d0879f3..e8d4a47 100644
--- a/test/Context/Fixtures/no-callback-process.php
+++ b/test/Context/Fixtures/no-callback-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 
diff --git a/test/Context/Fixtures/sleep-process.php b/test/Context/Fixtures/sleep-process.php
index aee7e2e..066080c 100644
--- a/test/Context/Fixtures/sleep-process.php
+++ b/test/Context/Fixtures/sleep-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 
diff --git a/test/Context/Fixtures/test-process.php b/test/Context/Fixtures/test-process.php
index cf6f25b..f1f796d 100644
--- a/test/Context/Fixtures/test-process.php
+++ b/test/Context/Fixtures/test-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\Sync\Channel;
 
diff --git a/test/Context/Fixtures/throwing-process.php b/test/Context/Fixtures/throwing-process.php
index 09fdc20..e296afd 100644
--- a/test/Context/Fixtures/throwing-process.php
+++ b/test/Context/Fixtures/throwing-process.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 use Amp\PHPUnit\TestException;
 use Amp\Sync\Channel;
diff --git a/test/Context/Internal/ExitFailureTest.php b/test/Context/Internal/ExitFailureTest.php
index dac2f3d..9bc0d9d 100644
--- a/test/Context/Internal/ExitFailureTest.php
+++ b/test/Context/Internal/ExitFailureTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Context\Internal;
 
diff --git a/test/Context/Internal/ExitSuccessTest.php b/test/Context/Internal/ExitSuccessTest.php
index 773087d..98cdb05 100644
--- a/test/Context/Internal/ExitSuccessTest.php
+++ b/test/Context/Internal/ExitSuccessTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Context\Internal;
 
diff --git a/test/Context/ProcessContextTest.php b/test/Context/ProcessContextTest.php
index 5c76934..def1903 100644
--- a/test/Context/ProcessContextTest.php
+++ b/test/Context/ProcessContextTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Context;
 
diff --git a/test/Worker/AbstractPoolTest.php b/test/Worker/AbstractPoolTest.php
index c04ca66..dd8d69e 100644
--- a/test/Worker/AbstractPoolTest.php
+++ b/test/Worker/AbstractPoolTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/AbstractWorkerTest.php b/test/Worker/AbstractWorkerTest.php
index c8975f0..b92bb53 100644
--- a/test/Worker/AbstractWorkerTest.php
+++ b/test/Worker/AbstractWorkerTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/DefaultPoolTest.php b/test/Worker/DefaultPoolTest.php
index 5816b51..0325fa8 100644
--- a/test/Worker/DefaultPoolTest.php
+++ b/test/Worker/DefaultPoolTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/DefaultWorkerFactoryTest.php b/test/Worker/DefaultWorkerFactoryTest.php
index 80109fa..8a1fae5 100644
--- a/test/Worker/DefaultWorkerFactoryTest.php
+++ b/test/Worker/DefaultWorkerFactoryTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/Fixtures/AutoloadTestTask.php b/test/Worker/Fixtures/AutoloadTestTask.php
index 0c162e7..d979318 100644
--- a/test/Worker/Fixtures/AutoloadTestTask.php
+++ b/test/Worker/Fixtures/AutoloadTestTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/CancellingTask.php b/test/Worker/Fixtures/CancellingTask.php
index 376b817..dd52ee2 100644
--- a/test/Worker/Fixtures/CancellingTask.php
+++ b/test/Worker/Fixtures/CancellingTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/CommunicatingTask.php b/test/Worker/Fixtures/CommunicatingTask.php
index 1664b0d..5376108 100644
--- a/test/Worker/Fixtures/CommunicatingTask.php
+++ b/test/Worker/Fixtures/CommunicatingTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/ConstantTask.php b/test/Worker/Fixtures/ConstantTask.php
index 45ee3bc..4cb52af 100644
--- a/test/Worker/Fixtures/ConstantTask.php
+++ b/test/Worker/Fixtures/ConstantTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/FailingTask.php b/test/Worker/Fixtures/FailingTask.php
index 5272caa..79e3fcb 100644
--- a/test/Worker/Fixtures/FailingTask.php
+++ b/test/Worker/Fixtures/FailingTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/NonAutoloadableResultTask.php b/test/Worker/Fixtures/NonAutoloadableResultTask.php
index 00c4e22..281333d 100644
--- a/test/Worker/Fixtures/NonAutoloadableResultTask.php
+++ b/test/Worker/Fixtures/NonAutoloadableResultTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/TestTask.php b/test/Worker/Fixtures/TestTask.php
index a61b28f..2a0830d 100644
--- a/test/Worker/Fixtures/TestTask.php
+++ b/test/Worker/Fixtures/TestTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/UnserializableResultTask.php b/test/Worker/Fixtures/UnserializableResultTask.php
index 6c376ed..edebd11 100644
--- a/test/Worker/Fixtures/UnserializableResultTask.php
+++ b/test/Worker/Fixtures/UnserializableResultTask.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/Fixtures/custom-bootstrap.php b/test/Worker/Fixtures/custom-bootstrap.php
index 5260ed6..4278042 100644
--- a/test/Worker/Fixtures/custom-bootstrap.php
+++ b/test/Worker/Fixtures/custom-bootstrap.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 spl_autoload_register(function (string $className) {
     if ($className !== CustomAutoloadClass::class) {
diff --git a/test/Worker/Fixtures/non-autoloadable-class.php b/test/Worker/Fixtures/non-autoloadable-class.php
index f80a144..c5aea85 100644
--- a/test/Worker/Fixtures/non-autoloadable-class.php
+++ b/test/Worker/Fixtures/non-autoloadable-class.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker\Fixtures;
 
diff --git a/test/Worker/FunctionsTest.php b/test/Worker/FunctionsTest.php
index 9f1b955..7ecaef4 100644
--- a/test/Worker/FunctionsTest.php
+++ b/test/Worker/FunctionsTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/JobTest.php b/test/Worker/JobTest.php
index 6689493..300395a 100644
--- a/test/Worker/JobTest.php
+++ b/test/Worker/JobTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/ProcessPoolTest.php b/test/Worker/ProcessPoolTest.php
index 432827c..918a15a 100644
--- a/test/Worker/ProcessPoolTest.php
+++ b/test/Worker/ProcessPoolTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/ProcessWorkerTest.php b/test/Worker/ProcessWorkerTest.php
index b4442bd..526ef61 100644
--- a/test/Worker/ProcessWorkerTest.php
+++ b/test/Worker/ProcessWorkerTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/TaskFailureErrorTest.php b/test/Worker/TaskFailureErrorTest.php
index 9d7a8eb..748a819 100644
--- a/test/Worker/TaskFailureErrorTest.php
+++ b/test/Worker/TaskFailureErrorTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/TaskFailureExceptionTest.php b/test/Worker/TaskFailureExceptionTest.php
index 9a4b19b..2b6c38a 100644
--- a/test/Worker/TaskFailureExceptionTest.php
+++ b/test/Worker/TaskFailureExceptionTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/TaskFailureTest.php b/test/Worker/TaskFailureTest.php
index 8c93278..17fbad0 100644
--- a/test/Worker/TaskFailureTest.php
+++ b/test/Worker/TaskFailureTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/TaskSuccessTest.php b/test/Worker/TaskSuccessTest.php
index 78ea732..06ff233 100644
--- a/test/Worker/TaskSuccessTest.php
+++ b/test/Worker/TaskSuccessTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;
 
diff --git a/test/Worker/WorkerExceptionTest.php b/test/Worker/WorkerExceptionTest.php
index 0e51735..6dd45f0 100644
--- a/test/Worker/WorkerExceptionTest.php
+++ b/test/Worker/WorkerExceptionTest.php
@@ -1,4 +1,4 @@
-<?php
+<?php declare(strict_types=1);
 
 namespace Amp\Parallel\Test\Worker;