diff --git a/src/Uri.php b/src/Uri.php
index d9833f63..b68ef7d5 100644
--- a/src/Uri.php
+++ b/src/Uri.php
@@ -111,6 +111,10 @@ class Uri implements UriInterface
      */
     public function __construct($uri = '')
     {
+        if ('' === $uri) {
+            return;
+        }
+
         if (! is_string($uri)) {
             throw new InvalidArgumentException(sprintf(
                 'URI passed to constructor must be a string; received "%s"',
@@ -118,9 +122,7 @@ public function __construct($uri = '')
             ));
         }
 
-        if ('' !== $uri) {
-            $this->parseUri($uri);
-        }
+        $this->parseUri($uri);
     }
 
     /**
@@ -282,7 +284,7 @@ public function withUserInfo($user, $password = null)
         }
         if (null !== $password && ! is_string($password)) {
             throw new InvalidArgumentException(sprintf(
-                '%s expects a string password argument; received %s',
+                '%s expects a string or null password argument; received %s',
                 __METHOD__,
                 (is_object($password) ? get_class($password) : gettype($password))
             ));
@@ -333,14 +335,14 @@ public function withHost($host)
      */
     public function withPort($port)
     {
-        if (! is_numeric($port) && $port !== null) {
-            throw new InvalidArgumentException(sprintf(
-                'Invalid port "%s" specified; must be an integer, an integer string, or null',
-                (is_object($port) ? get_class($port) : gettype($port))
-            ));
-        }
-
         if ($port !== null) {
+            if (! is_numeric($port) || is_float($port)) {
+                throw new InvalidArgumentException(sprintf(
+                    'Invalid port "%s" specified; must be an integer, an integer string, or null',
+                    (is_object($port) ? get_class($port) : gettype($port))
+                ));
+            }
+
             $port = (int) $port;
         }
 
@@ -559,7 +561,7 @@ private function filterScheme($scheme)
             return '';
         }
 
-        if (! array_key_exists($scheme, $this->allowedSchemes)) {
+        if (! isset($this->allowedSchemes[$scheme])) {
             throw new InvalidArgumentException(sprintf(
                 'Unsupported scheme "%s"; must be any empty string or in the set (%s)',
                 $scheme,
@@ -655,7 +657,7 @@ private function filterQuery($query)
     private function splitQueryValue($value)
     {
         $data = explode('=', $value, 2);
-        if (1 === count($data)) {
+        if (! isset($data[1])) {
             $data[] = null;
         }
         return $data;
diff --git a/test/UriTest.php b/test/UriTest.php
index f38c4b50..0e5f0ead 100644
--- a/test/UriTest.php
+++ b/test/UriTest.php
@@ -137,7 +137,7 @@ public function validPorts()
         return [
             'null'         => [ null ],
             'int'          => [ 3000 ],
-            'string'       => [ "3000" ],
+            'string-int'   => [ '3000' ],
         ];
     }
 
@@ -161,20 +161,21 @@ public function testWithPortReturnsSameInstanceWithProvidedPortIsSameAsBefore()
         $uri = new Uri('https://user:pass@local.example.com:3001/foo?bar=baz#quz');
         $new = $uri->withPort('3001');
         $this->assertSame($uri, $new);
-        $this->assertEquals('3001', $new->getPort());
+        $this->assertEquals(3001, $new->getPort());
     }
 
     public function invalidPorts()
     {
         return [
-            'true'      => [ true ],
-            'false'     => [ false ],
-            'string'    => [ 'string' ],
-            'array'     => [ [ 3000 ] ],
-            'object'    => [ (object) [ 3000 ] ],
-            'zero'      => [ 0 ],
-            'too-small' => [ -1 ],
-            'too-big'   => [ 65536 ],
+            'true'       => [ true ],
+            'false'      => [ false ],
+            'string'     => [ 'string' ],
+            'float'      => [ 55.5 ],
+            'array'      => [ [ 3000 ] ],
+            'object'     => [ (object) ['port' => 3000 ] ],
+            'zero'       => [ 0 ],
+            'too-small'  => [ -1 ],
+            'too-big'    => [ 65536 ],
         ];
     }