diff --git a/src/Collection.php b/src/Collection.php
index 015afd3..a1954c7 100644
--- a/src/Collection.php
+++ b/src/Collection.php
@@ -7,6 +7,7 @@
 use Closure;
 use Countable;
 use InvalidArgumentException;
+use Iterator;
 use IteratorAggregate;
 use Serializable;
 use stdClass;
@@ -17,23 +18,27 @@ final class Collection implements ArrayAccess, Countable, IteratorAggregate, Ser
 
     public function __construct($data = null)
     {
-        if ($data instanceof self) {
-            $this->data = $data->toArray();
+        if (is_object($data) && method_exists($data, "toArray")) {
+            $data = $data->toArray();
         }
 
-        if ($data instanceof stdClass) {
-            $this->data = (array) $data;
+        if ($data instanceof Iterator) {
+            $data = iterator_to_array($data);
+        }
+
+        if (is_object($data)) {
+            $data = (array) $data;
         }
 
         if (is_array($data)) {
             foreach ($data as $key => $value) {
-                if (is_array($value)) {
-                    $this->data[$key] = new self($value);
-                } else {
-                    $this->data[$key] = $value;
+                if (is_array($value) || is_object($value)) {
+                    $data[$key] = new self($value);
                 }
             }
         }
+
+        $this->data = $data;
     }
 
     public function offsetSet($key, $value)
@@ -112,7 +117,7 @@ public function serialize()
 
     public function unserialize($serialized)
     {
-        $this->data = unserialize($serialised);
+        $this->data = unserialize($serialized);
     }
 
     public function without(...$keys)
@@ -129,7 +134,7 @@ public function without(...$keys)
             $keys = $keys[0]->toArray();
         }
 
-        if (is_iterable($keys[0])) {
+        if ($keys[0] instanceof Iterator) {
             $keys = iterator_to_array($keys[0]);
         }
 
diff --git a/tests/CollectionTest.php b/tests/CollectionTest.php
index 71b58e1..44555a1 100644
--- a/tests/CollectionTest.php
+++ b/tests/CollectionTest.php
@@ -4,6 +4,7 @@
 
 use ArrayIterator;
 use InvalidArgumentException;
+use Iterator;
 use PHPUnit\Framework\TestCase;
 use Pre\Collections\Collection;
 
@@ -177,4 +178,216 @@ public function can_throw_with_no_without_keys()
         $this->expectException(InvalidArgumentException::class);
         (new Collection())->without();
     }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::__get
+     * @covers Pre\Collections\Collection::__set
+     */
+    public function can_get_and_set_values_with_arrows()
+    {
+        $collection = new Collection();
+
+        $this->assertNull($collection->hello);
+
+        $collection->hello = "world";
+
+        $this->assertEquals("world", $collection->hello);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::offsetSet
+     * @covers Pre\Collections\Collection::offsetGet
+     */
+    public function can_get_and_set_values_with_array_access()
+    {
+        $collection = new Collection();
+
+        $this->assertNull($collection["hello"]);
+
+        $collection["hello"] = "world";
+
+        $this->assertEquals("world", $collection["hello"]);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::__isset
+     * @covers Pre\Collections\Collection::offsetExists
+     */
+    public function can_always_show_isset()
+    {
+        $collection = new Collection();
+
+        $this->assertTrue(isset($collection->hello));
+        $this->assertNull($collection->hello);
+
+        $this->assertTrue(isset($collection["hello"]));
+        $this->assertNull($collection["hello"]);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::__unset
+     */
+    public function can_unset_with_arrows()
+    {
+        $collection = new Collection();
+        $collection->hello = "world";
+
+        $this->assertNotNull($collection->hello);
+
+        unset($collection->hello);
+
+        $this->assertNull($collection->hello);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::offsetUnset
+     */
+    public function can_unset_with_array_access()
+    {
+        $collection = new Collection();
+        $collection["hello"] = "world";
+
+        $this->assertNotNull($collection["hello"]);
+
+        unset($collection["hello"]);
+
+        $this->assertNull($collection["hello"]);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::toArray
+     */
+    public function can_convert_to_arrays()
+    {
+        $expected = [
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+            "nested" => [
+                "five" => 5
+            ]
+        ];
+
+        $collection = new Collection($expected);
+
+        $this->assertEquals($expected, $collection->toArray());
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::getIterator
+     */
+    public function can_get_iterators()
+    {
+        $expected = [
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ];
+
+        $collection = new Collection($expected);
+
+        $this->assertInstanceOf(Iterator::class, $collection->getIterator());
+        $this->assertEquals($expected, iterator_to_array($collection));
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::count
+     * @covers Pre\Collections\Collection::length
+     */
+    public function can_get_length()
+    {
+        $collection = new Collection([
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ]);
+
+        $this->assertEquals(3, count($collection));
+        $this->assertEquals(3, $collection->length());
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::serialize
+     * @covers Pre\Collections\Collection::unserialize
+     */
+    public function can_get_serialize_and_unserialize()
+    {
+        $collection = new Collection([
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ]);
+
+        $expected = 'C:26:"Pre\Collections\Collection":50:{a:3:{s:3:"one";i:1;s:3:"two";i:2;s:5:"three";i:3;}}';
+        $actual = serialize($collection);
+
+        $this->assertEquals($expected, $actual);
+        $this->assertEquals($collection, unserialize($actual));
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::with
+     */
+    public function can_add_values_using_with()
+    {
+        $collection = new Collection([
+            "one" => 1,
+            "two" => 2,
+        ]);
+
+        $new = $collection->with("three", 3);
+
+        $this->assertEquals(3, $new->three);
+        $this->assertNotSame($collection, $new);
+    }
+
+    /**
+     * @test
+     * @covers Pre\Collections\Collection::__construct
+     */
+    public function can_create_from_all_kinds_of_input()
+    {
+        $fromArray = new Collection([
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ]);
+
+        $fromObject = new Collection(
+            json_decode('{"one":1,"two":2,"three":3}')
+        );
+
+        $fromCollection = new Collection(new Collection([
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ]));
+
+        $fromIterator = new Collection(new ArrayIterator([
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ]));
+
+        $expected = [
+            "one" => 1,
+            "two" => 2,
+            "three" => 3,
+        ];
+
+        $this->assertEquals($expected, $fromArray->toArray());
+        $this->assertEquals($expected, $fromObject->toArray());
+        $this->assertEquals($expected, $fromCollection->toArray());
+        $this->assertEquals($expected, $fromIterator->toArray());
+    }
 }
diff --git a/tests/SpecTest.php b/tests/MacroTest.php
similarity index 83%
rename from tests/SpecTest.php
rename to tests/MacroTest.php
index 6867110..53644f0 100644
--- a/tests/SpecTest.php
+++ b/tests/MacroTest.php
@@ -4,7 +4,7 @@
 
 use Pre\Plugin\Testing\Runner;
 
-class SpecTest extends Runner
+class MacroTest extends Runner
 {
     protected function path(): string
     {