diff --git a/.travis.yml b/.travis.yml
index c9dec4b..6159a26 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,16 +3,14 @@ sudo: false
 language: php
 
 php:
-  - 7.0
   - 7.1
   - 7.2
   - 7.3
-  - 7.4snapshot
+  - 7.4
   - nightly
 
 matrix:
   allow_failures:
-    - php: 7.4snapshot
     - php: nightly
   fast_finish: true
 
diff --git a/composer.json b/composer.json
index 5688028..ab65a01 100644
--- a/composer.json
+++ b/composer.json
@@ -19,16 +19,17 @@
         }
     ],
     "require": {
-        "php": "^7.0",
+        "php": "^7.1",
         "amphp/amp": "^2",
         "amphp/sql": "^1",
         "amphp/sql-common": "^1"
     },
     "require-dev": {
+        "ext-pgsql": "*",
+        "ext-pq": "*",
         "amphp/phpunit-util": "^1.1.2",
-        "phpunit/phpunit": "^7 || ^6",
-        "amphp/php-cs-fixer-config": "dev-master",
-        "phpstan/phpstan": "^0.9"
+        "phpunit/phpunit": "^8 | ^7",
+        "amphp/php-cs-fixer-config": "dev-master"
     },
     "autoload": {
         "psr-4": {
@@ -44,11 +45,6 @@
             "Amp\\Postgres\\Test\\": "test"
         }
     },
-    "config": {
-        "platform": {
-            "php": "7.0.0"
-        }
-    },
     "scripts": {
         "check": [
             "@cs",
diff --git a/src/Connection.php b/src/Connection.php
index 558b04b..8a8aa12 100644
--- a/src/Connection.php
+++ b/src/Connection.php
@@ -2,7 +2,6 @@
 
 namespace Amp\Postgres;
 
-use Amp\CallableMaker;
 use Amp\CancellationToken;
 use Amp\Deferred;
 use Amp\Promise;
@@ -13,8 +12,6 @@ use function Amp\call;
 
 abstract class Connection implements Link, Handle
 {
-    use CallableMaker;
-
     /** @var Handle */
     private $handle;
 
@@ -27,7 +24,7 @@ abstract class Connection implements Link, Handle
      *
      * @return Promise<Connection>
      */
-    abstract public static function connect(ConnectionConfig $connectionConfig, CancellationToken $token = null): Promise;
+    abstract public static function connect(ConnectionConfig $connectionConfig, ?CancellationToken $token = null): Promise;
 
     /**
      * @param Handle $handle
@@ -63,7 +60,7 @@ abstract class Connection implements Link, Handle
     /**
      * {@inheritdoc}
      */
-    final public function close()
+    final public function close(): void
     {
         if ($this->handle) {
             $this->handle->close();
@@ -100,7 +97,7 @@ abstract class Connection implements Link, Handle
     /**
      * Releases the transaction lock.
      */
-    private function release()
+    private function release(): void
     {
         \assert($this->busy !== null);
 
@@ -209,7 +206,7 @@ abstract class Connection implements Link, Handle
 
             $this->busy = new Deferred;
 
-            return new ConnectionTransaction($this->handle, $this->callableFromInstanceMethod("release"), $isolation);
+            return new ConnectionTransaction($this->handle, \Closure::fromCallable([$this, 'release']), $isolation);
         });
     }
 
diff --git a/src/ConnectionTransaction.php b/src/ConnectionTransaction.php
index 3600d63..b93bf67 100644
--- a/src/ConnectionTransaction.php
+++ b/src/ConnectionTransaction.php
@@ -72,7 +72,7 @@ final class ConnectionTransaction implements Transaction
      *
      * Closes and commits all changes in the transaction.
      */
-    public function close()
+    public function close(): void
     {
         if ($this->handle) {
             $this->commit(); // Invokes $this->release callback.
diff --git a/src/Internal/functions.php b/src/Internal/functions.php
index 86a9b38..e3765dd 100644
--- a/src/Internal/functions.php
+++ b/src/Internal/functions.php
@@ -10,14 +10,14 @@ REGEX;
 
 /**
  * @param string $sql SQL statement with named and unnamed placeholders.
- * @param array $names Array of parameter positions mapped to names and/or indexed locations.
+ * @param array $names [Output] Array of parameter positions mapped to names and/or indexed locations.
  *
  * @return string SQL statement with Postgres-style placeholders
  */
-function parseNamedParams(string $sql, array &$names = null): string
+function parseNamedParams(string $sql, ?array &$names): string
 {
     $names = [];
-    return \preg_replace_callback(STATEMENT_PARAM_REGEX, function (array $matches) use (&$names) {
+    return \preg_replace_callback(STATEMENT_PARAM_REGEX, function (array $matches) use (&$names): string {
         static $index = 0, $unnamed = 0, $numbered = 1;
 
         if (isset($matches[4])) {
diff --git a/src/PgSqlConnection.php b/src/PgSqlConnection.php
index d9c2ade..56c2612 100644
--- a/src/PgSqlConnection.php
+++ b/src/PgSqlConnection.php
@@ -2,7 +2,6 @@
 
 namespace Amp\Postgres;
 
-use Amp\CallableMaker;
 use Amp\CancellationToken;
 use Amp\Deferred;
 use Amp\Failure;
@@ -13,8 +12,6 @@ use Amp\Sql\ConnectionException;
 
 final class PgSqlConnection extends Connection implements Link
 {
-    use CallableMaker;
-
     /**
      * @param ConnectionConfig $connectionConfig
      * @param CancellationToken $token
@@ -23,7 +20,7 @@ final class PgSqlConnection extends Connection implements Link
      *
      * @throws \Error If pecl-ev is used as a loop extension.
      */
-    public static function connect(ConnectionConfig $connectionConfig, CancellationToken $token = null): Promise
+    public static function connect(ConnectionConfig $connectionConfig, ?CancellationToken $token = null): Promise
     {
         // @codeCoverageIgnoreStart
         if (Loop::get()->getHandle() instanceof \EvLoop) {
@@ -72,7 +69,7 @@ final class PgSqlConnection extends Connection implements Link
         $token = $token ?? new NullCancellationToken();
         $id = $token->subscribe([$deferred, "fail"]);
 
-        $promise->onResolve(function ($exception) use ($connection, $poll, $await, $id, $token) {
+        $promise->onResolve(function ($exception) use ($connection, $poll, $await, $id, $token): void {
             if ($exception) {
                 \pg_close($connection);
             }
diff --git a/src/PgSqlHandle.php b/src/PgSqlHandle.php
index a87404b..ef0c699 100644
--- a/src/PgSqlHandle.php
+++ b/src/PgSqlHandle.php
@@ -2,7 +2,6 @@
 
 namespace Amp\Postgres;
 
-use Amp\CallableMaker;
 use Amp\Deferred;
 use Amp\Emitter;
 use Amp\Loop;
@@ -16,8 +15,6 @@ use function Amp\call;
 
 final class PgSqlHandle implements Handle
 {
-    use CallableMaker;
-
     const DIAGNOSTIC_CODES = [
         \PGSQL_DIAG_SEVERITY => "severity",
         \PGSQL_DIAG_SQLSTATE => "sqlstate",
@@ -48,9 +45,6 @@ final class PgSqlHandle implements Handle
     /** @var \Amp\Emitter[] */
     private $listeners = [];
 
-    /** @var callable */
-    private $unlisten;
-
     /** @var Struct[] */
     private $statements = [];
 
@@ -74,7 +68,7 @@ final class PgSqlHandle implements Handle
         $deferred = &$this->deferred;
         $listeners = &$this->listeners;
 
-        $this->poll = Loop::onReadable($socket, static function ($watcher) use (&$deferred, &$lastUsedAt, &$listeners, &$handle) {
+        $this->poll = Loop::onReadable($socket, static function ($watcher) use (&$deferred, &$lastUsedAt, &$listeners, &$handle): void {
             $lastUsedAt = \time();
 
             if (!\pg_consume_input($handle)) {
@@ -123,7 +117,7 @@ final class PgSqlHandle implements Handle
             }
         });
 
-        $this->await = Loop::onWritable($socket, static function ($watcher) use (&$deferred, &$listeners, &$handle) {
+        $this->await = Loop::onWritable($socket, static function ($watcher) use (&$deferred, &$listeners, &$handle): void {
             $flush = \pg_flush($handle);
             if ($flush === 0) {
                 return; // Not finished sending data, listen again.
@@ -147,8 +141,6 @@ final class PgSqlHandle implements Handle
 
         Loop::disable($this->poll);
         Loop::disable($this->await);
-
-        $this->unlisten = $this->callableFromInstanceMethod("unlisten");
     }
 
     /**
@@ -162,7 +154,7 @@ final class PgSqlHandle implements Handle
     /**
      * {@inheritdoc}
      */
-    public function close()
+    public function close(): void
     {
         if ($this->deferred) {
             $deferred = $this->deferred;
@@ -175,7 +167,7 @@ final class PgSqlHandle implements Handle
         $this->handle = null;
     }
 
-    private function free()
+    private function free(): void
     {
         if (\is_resource($this->handle)) {
             \pg_close($this->handle);
@@ -458,7 +450,7 @@ final class PgSqlHandle implements Handle
             }
 
             Loop::enable($this->poll);
-            return new ConnectionListener($emitter->iterate(), $channel, $this->unlisten);
+            return new ConnectionListener($emitter->iterate(), $channel, \Closure::fromCallable([$this, 'unlisten']));
         });
     }
 
diff --git a/src/Pool.php b/src/Pool.php
index b468c79..bec00e7 100644
--- a/src/Pool.php
+++ b/src/Pool.php
@@ -37,7 +37,7 @@ final class Pool extends ConnectionPool implements Link
         int $maxConnections = self::DEFAULT_MAX_CONNECTIONS,
         int $idleTimeout = self::DEFAULT_IDLE_TIMEOUT,
         bool $resetConnections = true,
-        Connector $connector = null
+        ?Connector $connector = null
     ) {
         parent::__construct($config, $maxConnections, $idleTimeout, $connector);
 
diff --git a/src/PooledListener.php b/src/PooledListener.php
index 4d393d2..2d723b7 100644
--- a/src/PooledListener.php
+++ b/src/PooledListener.php
@@ -35,7 +35,7 @@ final class PooledListener implements Listener
         return $this->listener->advance();
     }
 
-    public function getCurrent()
+    public function getCurrent(): Notification
     {
         return $this->listener->getCurrent();
     }
diff --git a/src/PqConnection.php b/src/PqConnection.php
index 1e4d009..c2d7925 100644
--- a/src/PqConnection.php
+++ b/src/PqConnection.php
@@ -22,7 +22,7 @@ final class PqConnection extends Connection implements Link
      *
      * @return Promise<PqConnection>
      */
-    public static function connect(ConnectionConfig $connectionConfig, CancellationToken $token = null): Promise
+    public static function connect(ConnectionConfig $connectionConfig, ?CancellationToken $token = null): Promise
     {
         $connectionString = \str_replace(";", " ", $connectionConfig->getConnectionString());
 
@@ -63,7 +63,7 @@ final class PqConnection extends Connection implements Link
         $token = $token ?? new NullCancellationToken();
         $id = $token->subscribe([$deferred, "fail"]);
 
-        $promise->onResolve(function () use ($poll, $await, $id, $token) {
+        $promise->onResolve(function () use ($poll, $await, $id, $token): void {
             $token->unsubscribe($id);
             Loop::cancel($poll);
             Loop::cancel($await);
@@ -92,7 +92,7 @@ final class PqConnection extends Connection implements Link
     /**
      * Sets result sets to be fully buffered in local memory.
      */
-    public function shouldBufferResults()
+    public function shouldBufferResults(): void
     {
         $this->handle->shouldBufferResults();
     }
@@ -100,7 +100,7 @@ final class PqConnection extends Connection implements Link
     /**
      * Sets result sets to be streamed from the database server.
      */
-    public function shouldNotBufferResults()
+    public function shouldNotBufferResults(): void
     {
         $this->handle->shouldNotBufferResults();
     }
diff --git a/src/PqHandle.php b/src/PqHandle.php
index f795108..4a25111 100644
--- a/src/PqHandle.php
+++ b/src/PqHandle.php
@@ -2,7 +2,6 @@
 
 namespace Amp\Postgres;
 
-use Amp\CallableMaker;
 use Amp\Coroutine;
 use Amp\Deferred;
 use Amp\Emitter;
@@ -19,8 +18,6 @@ use function Amp\coroutine;
 
 final class PqHandle implements Handle
 {
-    use CallableMaker;
-
     /** @var \pq\Connection PostgreSQL connection object. */
     private $handle;
 
@@ -42,15 +39,6 @@ final class PqHandle implements Handle
     /** @var Struct[] */
     private $statements = [];
 
-    /** @var callable */
-    private $fetch;
-
-    /** @var callable */
-    private $unlisten;
-
-    /** @var callable */
-    private $release;
-
     /** @var int */
     private $lastUsedAt;
 
@@ -69,7 +57,7 @@ final class PqHandle implements Handle
         $deferred = &$this->deferred;
         $listeners = &$this->listeners;
 
-        $this->poll = Loop::onReadable($this->handle->socket, static function ($watcher) use (&$deferred, &$lastUsedAt, &$listeners, &$handle) {
+        $this->poll = Loop::onReadable($this->handle->socket, static function ($watcher) use (&$deferred, &$lastUsedAt, &$listeners, &$handle): void {
             $lastUsedAt = \time();
 
             if ($handle->poll() === pq\Connection::POLLING_FAILED) {
@@ -103,7 +91,7 @@ final class PqHandle implements Handle
             }
         });
 
-        $this->await = Loop::onWritable($this->handle->socket, static function ($watcher) use (&$deferred, &$listeners, &$handle) {
+        $this->await = Loop::onWritable($this->handle->socket, static function ($watcher) use (&$deferred, &$listeners, &$handle): void {
             try {
                 if (!$handle->flush()) {
                     return; // Not finished sending data, continue polling for writability.
@@ -126,10 +114,6 @@ final class PqHandle implements Handle
 
         Loop::disable($this->poll);
         Loop::disable($this->await);
-
-        $this->fetch = coroutine($this->callableFromInstanceMethod("fetch"));
-        $this->unlisten = $this->callableFromInstanceMethod("unlisten");
-        $this->release = $this->callableFromInstanceMethod("release");
     }
 
     /**
@@ -159,7 +143,7 @@ final class PqHandle implements Handle
     /**
      * {@inheritdoc}
      */
-    public function close()
+    public function close(): void
     {
         if ($this->deferred) {
             $deferred = $this->deferred;
@@ -172,7 +156,7 @@ final class PqHandle implements Handle
         $this->free();
     }
 
-    private function free()
+    private function free(): void
     {
         Loop::cancel($this->poll);
         Loop::cancel($this->await);
@@ -239,7 +223,11 @@ final class PqHandle implements Handle
 
             case pq\Result::SINGLE_TUPLE:
                 $this->busy = new Deferred;
-                $result = new PqUnbufferedResultSet($this->fetch, $result, $this->release);
+                $result = new PqUnbufferedResultSet(
+                    coroutine(\Closure::fromCallable([$this, 'fetch'])),
+                    $result,
+                    \Closure::fromCallable([$this, 'release'])
+                );
                 return $result;
 
             case pq\Result::NONFATAL_ERROR:
@@ -289,7 +277,7 @@ final class PqHandle implements Handle
         }
     }
 
-    private function release()
+    private function release(): void
     {
         \assert(
             $this->busy instanceof Deferred && $this->busy !== $this->deferred,
@@ -465,7 +453,7 @@ final class PqHandle implements Handle
             }
 
             Loop::enable($this->poll);
-            return new ConnectionListener($emitter->iterate(), $channel, $this->unlisten);
+            return new ConnectionListener($emitter->iterate(), $channel, \Closure::fromCallable([$this, 'unlisten']));
         });
     }
 
diff --git a/src/functions.php b/src/functions.php
index aac3ec3..49c0613 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -10,7 +10,7 @@ use Amp\Sql\Connector;
 
 const LOOP_CONNECTOR_IDENTIFIER = Connector::class . "\\Postgres";
 
-function connector(Connector $connector = null): Connector
+function connector(?Connector $connector = null): Connector
 {
     if ($connector === null) {
         $connector = Loop::getState(LOOP_CONNECTOR_IDENTIFIER);
diff --git a/test/AbstractLinkTest.php b/test/AbstractLinkTest.php
index 4b5650e..49be982 100644
--- a/test/AbstractLinkTest.php
+++ b/test/AbstractLinkTest.php
@@ -27,7 +27,7 @@ abstract class AbstractLinkTest extends AsyncTestCase
     /**
      * @return array Start test data for database.
      */
-    public function getData()
+    public function getData(): array
     {
         return [
             ['amphp', 'org'],
@@ -44,7 +44,7 @@ abstract class AbstractLinkTest extends AsyncTestCase
      */
     abstract public function createLink(string $connectionString): Link;
 
-    public function setUp()
+    public function setUp(): void
     {
         parent::setUp();
         $this->connection = $this->createLink('host=localhost user=postgres');
@@ -100,11 +100,10 @@ abstract class AbstractLinkTest extends AsyncTestCase
         $this->assertSame(1, $result->getAffectedRowCount());
     }
 
-    /**
-     * @expectedException \Amp\Sql\QueryError
-     */
     public function testQueryWithEmptyQuery(): Promise
     {
+        $this->expectException(QueryError::class);
+
         /** @var \Amp\Sql\CommandResult $result */
         return $this->connection->query('');
     }
diff --git a/test/ArrayParserTest.php b/test/ArrayParserTest.php
index 0f0cd48..cb59460 100644
--- a/test/ArrayParserTest.php
+++ b/test/ArrayParserTest.php
@@ -11,12 +11,12 @@ class ArrayParserTest extends TestCase
     /** @var \Amp\Postgres\Internal\ArrayParser */
     private $parser;
 
-    public function setUp()
+    public function setUp(): void
     {
         $this->parser = new ArrayParser;
     }
 
-    public function testSingleDimensionalArray()
+    public function testSingleDimensionalArray(): void
     {
         $array = ["one", "two", "three"];
         $string = '{' . \implode(',', $array) . '}';
@@ -24,7 +24,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testMultiDimensionalArray()
+    public function testMultiDimensionalArray(): void
     {
         $array = ["one", "two", ["three", "four"], "five"];
         $string = '{one, two, {three, four}, five}';
@@ -32,7 +32,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testQuotedStrings()
+    public function testQuotedStrings(): void
     {
         $array = ["one", "two", ["three", "four"], "five"];
         $string = '{"one", "two", {"three", "four"}, "five"}';
@@ -40,7 +40,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testAlternateDelimiter()
+    public function testAlternateDelimiter(): void
     {
         $array = ["1,2,3", "3,4,5"];
         $string = '{1,2,3;3,4,5}';
@@ -48,7 +48,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, null, ';'));
     }
 
-    public function testEscapedQuoteDelimiter()
+    public function testEscapedQuoteDelimiter(): void
     {
         $array = ['va"lue1', 'value"2'];
         $string = '{"va\\"lue1", "value\\"2"}';
@@ -56,7 +56,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, null, ','));
     }
 
-    public function testNullValue()
+    public function testNullValue(): void
     {
         $array = ["one", null, "three"];
         $string = '{one, NULL, three}';
@@ -64,7 +64,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testQuotedNullValue()
+    public function testQuotedNullValue(): void
     {
         $array = ["one", "NULL", "three"];
         $string = '{one, "NULL", three}';
@@ -72,7 +72,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testCast()
+    public function testCast(): void
     {
         $array = [1, 2, 3];
         $string = '{' . \implode(',', $array) . '}';
@@ -84,7 +84,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, $cast));
     }
 
-    public function testCastWithNull()
+    public function testCastWithNull(): void
     {
         $array = [1, 2, null, 3];
         $string = '{1,2,NULL,3}';
@@ -96,7 +96,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, $cast));
     }
 
-    public function testCastWithMultidimensionalArray()
+    public function testCastWithMultidimensionalArray(): void
     {
         $array = [1, 2, [3, 4], [5], 6, 7, [[8, 9], 10]];
         $string = '{1,2,{3,4},{5},6,7,{{8,9},10}}';
@@ -108,7 +108,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, $cast));
     }
 
-    public function testRandomWhitespace()
+    public function testRandomWhitespace(): void
     {
         $array = [1, 2, [3, 4], [5], 6, 7, [[8, 9], 10]];
         $string = " {1, 2, { 3 ,\r 4 },{ 5} \n\t ,6 , 7, { {8,\t 9}, 10} }  \n";
@@ -120,7 +120,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, $cast));
     }
 
-    public function testEscapedBackslashesInQuotedValue()
+    public function testEscapedBackslashesInQuotedValue(): void
     {
         $array = ["test\\ing", "esca\\ped\\"];
         $string = '{"test\\\\ing", "esca\\\\ped\\\\"}';
@@ -128,7 +128,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testEmptyArray()
+    public function testEmptyArray(): void
     {
         $array = [];
         $string = '{}';
@@ -136,7 +136,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testArrayContainingEmptyArray()
+    public function testArrayContainingEmptyArray(): void
     {
         $array = [[], [1], []];
         $string = '{{},{1},{}}';
@@ -148,7 +148,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string, $cast));
     }
 
-    public function testArrayWithEmptyString()
+    public function testArrayWithEmptyString(): void
     {
         $array = [''];
         $string = '{""}';
@@ -156,7 +156,7 @@ class ArrayParserTest extends TestCase
         $this->assertSame($array, $this->parser->parse($string));
     }
 
-    public function testMalformedNestedArray()
+    public function testMalformedNestedArray(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Unexpected end of data');
@@ -165,7 +165,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testEmptyString()
+    public function testEmptyString(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Unexpected end of data');
@@ -174,7 +174,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testNoOpeningBracket()
+    public function testNoOpeningBracket(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Missing opening bracket');
@@ -183,7 +183,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testNoClosingBracket()
+    public function testNoClosingBracket(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Unexpected end of data');
@@ -192,7 +192,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testExtraClosingBracket()
+    public function testExtraClosingBracket(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Data left in buffer after parsing');
@@ -201,7 +201,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testTrailingData()
+    public function testTrailingData(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Data left in buffer after parsing');
@@ -210,7 +210,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testMissingQuote()
+    public function testMissingQuote(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Could not find matching quote in quoted value');
@@ -219,7 +219,7 @@ class ArrayParserTest extends TestCase
         $this->parser->parse($string);
     }
 
-    public function testInvalidDelimiter()
+    public function testInvalidDelimiter(): void
     {
         $this->expectException(ParseException::class);
         $this->expectExceptionMessage('Invalid delimiter');
diff --git a/test/ConnectionConfigTest.php b/test/ConnectionConfigTest.php
index 16f12a7..99206e7 100644
--- a/test/ConnectionConfigTest.php
+++ b/test/ConnectionConfigTest.php
@@ -7,7 +7,7 @@ use PHPUnit\Framework\TestCase;
 
 class ConnectionConfigTest extends TestCase
 {
-    public function testBasicSyntax()
+    public function testBasicSyntax(): void
     {
         $config = ConnectionConfig::fromString("host=localhost port=5434 user=postgres password=test db=test");
 
@@ -18,7 +18,7 @@ class ConnectionConfigTest extends TestCase
         $this->assertSame($config->getDatabase(), "test");
     }
 
-    public function testAlternativeSyntax()
+    public function testAlternativeSyntax(): void
     {
         $config = ConnectionConfig::fromString("host=localhost;port=5434;user=postgres;password=test;db=test");
 
@@ -29,14 +29,14 @@ class ConnectionConfigTest extends TestCase
         $this->assertSame($config->getDatabase(), "test");
     }
 
-    public function testNoHost()
+    public function testNoHost(): void
     {
         $this->expectException(\Error::class);
         $this->expectExceptionMessage("Host must be provided in connection string");
         $config = ConnectionConfig::fromString("user=postgres");
     }
 
-    public function testInvalidString()
+    public function testInvalidString(): void
     {
         $this->expectException(\Error::class);
         $this->expectExceptionMessage("Host must be provided in connection string");
diff --git a/test/EncodeTest.php b/test/EncodeTest.php
index 552115b..0ea160d 100644
--- a/test/EncodeTest.php
+++ b/test/EncodeTest.php
@@ -7,7 +7,7 @@ use function Amp\Postgres\encode;
 
 class EncodeTest extends TestCase
 {
-    public function testSingleDimensionalStringArray()
+    public function testSingleDimensionalStringArray(): void
     {
         $array = ["one", "two", "three"];
         $string = '{"one","two","three"}';
@@ -15,7 +15,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testMultiDimensionalStringArray()
+    public function testMultiDimensionalStringArray(): void
     {
         $array = ["one", "two", ["three", "four"], "five"];
         $string = '{"one","two",{"three","four"},"five"}';
@@ -23,7 +23,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testQuotedStrings()
+    public function testQuotedStrings(): void
     {
         $array = ["one", "two", ["three", "four"], "five"];
         $string = '{"one","two",{"three","four"},"five"}';
@@ -31,7 +31,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testEscapedQuoteDelimiter()
+    public function testEscapedQuoteDelimiter(): void
     {
         $array = ['va"lue1', 'value"2'];
         $string = '{"va\\"lue1","value\\"2"}';
@@ -39,7 +39,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testNullValue()
+    public function testNullValue(): void
     {
         $array = ["one", null, "three"];
         $string = '{"one",NULL,"three"}';
@@ -47,7 +47,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testSingleDimensionalIntegerArray()
+    public function testSingleDimensionalIntegerArray(): void
     {
         $array = [1, 2, 3];
         $string = '{' . \implode(',', $array) . '}';
@@ -55,7 +55,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testIntegerArrayWithNull()
+    public function testIntegerArrayWithNull(): void
     {
         $array = [1, 2, null, 3];
         $string = '{1,2,NULL,3}';
@@ -63,7 +63,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testMultidimensionalIntegerArray()
+    public function testMultidimensionalIntegerArray(): void
     {
         $array = [1, 2, [3, 4], [5], 6, 7, [[8, 9], 10]];
         $string = '{1,2,{3,4},{5},6,7,{{8,9},10}}';
@@ -71,7 +71,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testEscapedBackslashesInQuotedValue()
+    public function testEscapedBackslashesInQuotedValue(): void
     {
         $array = ["test\\ing", "esca\\ped\\"];
         $string = '{"test\\\\ing","esca\\\\ped\\\\"}';
@@ -79,7 +79,7 @@ class EncodeTest extends TestCase
         $this->assertSame($string, encode($array));
     }
 
-    public function testObjectWithoutToStringMethod()
+    public function testObjectWithoutToStringMethod(): void
     {
         $this->expectException(\Error::class);
         $this->expectExceptionMessage('Object without a __toString() method in array');
diff --git a/test/FunctionsTest.php b/test/FunctionsTest.php
index 934de73..bfbbe7c 100644
--- a/test/FunctionsTest.php
+++ b/test/FunctionsTest.php
@@ -11,7 +11,7 @@ use function Amp\Postgres\connect;
 
 class FunctionsTest extends AsyncTestCase
 {
-    public function setUp()
+    public function setUp(): void
     {
         parent::setUp();
 
diff --git a/test/PgSqlConnectionTest.php b/test/PgSqlConnectionTest.php
index bb1cfb5..6aea83c 100644
--- a/test/PgSqlConnectionTest.php
+++ b/test/PgSqlConnectionTest.php
@@ -42,7 +42,7 @@ class PgSqlConnectionTest extends AbstractConnectionTest
         return new PgSqlConnection($this->handle, $socket);
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         \pg_get_result($this->handle); // Consume any leftover results from test.
         \pg_query($this->handle, "ROLLBACK");
diff --git a/test/PgSqlPoolTest.php b/test/PgSqlPoolTest.php
index 22935c0..b0331a2 100644
--- a/test/PgSqlPoolTest.php
+++ b/test/PgSqlPoolTest.php
@@ -66,7 +66,7 @@ class PgSqlPoolTest extends AbstractLinkTest
         return $pool;
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         foreach ($this->handles as $handle) {
             \pg_get_result($handle); // Consume any leftover results from test.
diff --git a/test/PqConnectionTest.php b/test/PqConnectionTest.php
index 2031b38..445a612 100644
--- a/test/PqConnectionTest.php
+++ b/test/PqConnectionTest.php
@@ -41,7 +41,7 @@ class PqConnectionTest extends AbstractConnectionTest
         return new PqConnection($this->handle);
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         $this->handle->exec("ROLLBACK");
         $this->handle->exec("DROP TABLE test");
@@ -73,26 +73,24 @@ class PqConnectionTest extends AbstractConnectionTest
     /**
      * @depends testBufferedResults
      */
-    public function testUnbufferedResults()
+    public function testUnbufferedResults(): \Generator
     {
-        Loop::run(function () {
-            \assert($this->connection instanceof PqConnection);
-            $this->connection->shouldNotBufferResults();
+        \assert($this->connection instanceof PqConnection);
+        $this->connection->shouldNotBufferResults();
 
-            $this->assertFalse($this->connection->isBufferingResults());
+        $this->assertFalse($this->connection->isBufferingResults());
 
-            $result = yield $this->connection->query("SELECT * FROM test");
-            \assert($result instanceof PqUnbufferedResultSet);
+        $result = yield $this->connection->query("SELECT * FROM test");
+        \assert($result instanceof PqUnbufferedResultSet);
 
-            $this->assertSame(2, $result->getFieldCount());
+        $this->assertSame(2, $result->getFieldCount());
 
-            $data = $this->getData();
+        $data = $this->getData();
 
-            for ($i = 0; yield $result->advance(); ++$i) {
-                $row = $result->getCurrent();
-                $this->assertSame($data[$i][0], $row['domain']);
-                $this->assertSame($data[$i][1], $row['tld']);
-            }
-        });
+        for ($i = 0; yield $result->advance(); ++$i) {
+            $row = $result->getCurrent();
+            $this->assertSame($data[$i][0], $row['domain']);
+            $this->assertSame($data[$i][1], $row['tld']);
+        }
     }
 }
diff --git a/test/PqPoolTest.php b/test/PqPoolTest.php
index d9243e9..7b56acc 100644
--- a/test/PqPoolTest.php
+++ b/test/PqPoolTest.php
@@ -63,7 +63,7 @@ class PqPoolTest extends AbstractLinkTest
         return $pool;
     }
 
-    public function tearDown()
+    public function tearDown(): void
     {
         $this->handles[0]->exec("ROLLBACK");
         $this->handles[0]->exec("DROP TABLE test");