diff --git a/src/PseudoTypes/NonEmptyArray.php b/src/PseudoTypes/NonEmptyArray.php
index d353686..4aa3720 100644
--- a/src/PseudoTypes/NonEmptyArray.php
+++ b/src/PseudoTypes/NonEmptyArray.php
@@ -39,7 +39,7 @@ public function __toString(): string
         }
 
         if ($this->keyType) {
-            return 'non-empty-array<' . $this->keyType . ',' . $this->valueType . '>';
+            return 'non-empty-array<' . $this->keyType . ', ' . $this->valueType . '>';
         }
 
         return 'non-empty-array<' . $this->valueType . '>';
diff --git a/src/Types/AbstractList.php b/src/Types/AbstractList.php
index 32eb0f2..83f032d 100644
--- a/src/Types/AbstractList.php
+++ b/src/Types/AbstractList.php
@@ -81,7 +81,7 @@ public function __toString(): string
         }
 
         if ($this->keyType) {
-            return 'array<' . $this->keyType . ',' . $this->valueType . '>';
+            return 'array<' . $this->keyType . ', ' . $this->valueType . '>';
         }
 
         if ($this->valueType instanceof Compound) {
diff --git a/src/Types/Iterable_.php b/src/Types/Iterable_.php
index f7d2264..3ac6ef6 100644
--- a/src/Types/Iterable_.php
+++ b/src/Types/Iterable_.php
@@ -30,7 +30,7 @@ public function __toString(): string
         }
 
         if ($this->keyType) {
-            return 'iterable<' . $this->keyType . ',' . $this->valueType . '>';
+            return 'iterable<' . $this->keyType . ', ' . $this->valueType . '>';
         }
 
         return 'iterable<' . $this->valueType . '>';
diff --git a/tests/unit/CollectionResolverTest.php b/tests/unit/CollectionResolverTest.php
index 815cb96..407ae41 100644
--- a/tests/unit/CollectionResolverTest.php
+++ b/tests/unit/CollectionResolverTest.php
@@ -102,10 +102,10 @@ public function testResolvingArrayCollectionWithKey(): void
     {
         $fixture = new TypeResolver();
 
-        $resolvedType = $fixture->resolve('array<string,object|array>', new Context(''));
+        $resolvedType = $fixture->resolve('array<string, object|array>', new Context(''));
 
         $this->assertInstanceOf(Array_::class, $resolvedType);
-        $this->assertSame('array<string,object|array>', (string) $resolvedType);
+        $this->assertSame('array<string, object|array>', (string) $resolvedType);
 
         $valueType = $resolvedType->getValueType();
 
@@ -127,7 +127,7 @@ public function testResolvingArrayCollectionWithKeyAndWhitespace(): void
         $resolvedType = $fixture->resolve('array<string, object|array>', new Context(''));
 
         $this->assertInstanceOf(Array_::class, $resolvedType);
-        $this->assertSame('array<string,object|array>', (string) $resolvedType);
+        $this->assertSame('array<string, object|array>', (string) $resolvedType);
 
         $valueType = $resolvedType->getValueType();
 
@@ -170,16 +170,16 @@ public function testResolvingCollectionOfCollection(): void
     public function testGoodArrayCollectionKey(): void
     {
         $fixture = new TypeResolver();
-        $resolvedType = $fixture->resolve('array<array-key,string>', new Context(''));
+        $resolvedType = $fixture->resolve('array<array-key, string>', new Context(''));
 
         $this->assertInstanceOf(Array_::class, $resolvedType);
-        $this->assertSame('array<array-key,string>', (string) $resolvedType);
+        $this->assertSame('array<array-key, string>', (string) $resolvedType);
 
         $fixture = new TypeResolver();
-        $resolvedType = $fixture->resolve('array<class-string,string>', new Context(''));
+        $resolvedType = $fixture->resolve('array<class-string, string>', new Context(''));
 
         $this->assertInstanceOf(Array_::class, $resolvedType);
-        $this->assertSame('array<class-string,string>', (string) $resolvedType);
+        $this->assertSame('array<class-string, string>', (string) $resolvedType);
     }
 
     public function testMissingStartCollection(): void
@@ -218,7 +218,7 @@ public function testResolvingCollectionAsArray(): void
         $resolvedType = $fixture->resolve('array<string,float>', new Context(''));
 
         $this->assertInstanceOf(Array_::class, $resolvedType);
-        $this->assertSame('array<string,float>', (string) $resolvedType);
+        $this->assertSame('array<string, float>', (string) $resolvedType);
 
         $valueType = $resolvedType->getValueType();
 
diff --git a/tests/unit/PseudoTypes/NonEmptyArrayTest.php b/tests/unit/PseudoTypes/NonEmptyArrayTest.php
index bc3bc18..50abda7 100644
--- a/tests/unit/PseudoTypes/NonEmptyArrayTest.php
+++ b/tests/unit/PseudoTypes/NonEmptyArrayTest.php
@@ -56,7 +56,7 @@ public function provideToStringData(): array
                         new Compound([new Integer(), new String_()]),
                         new String_()
                     ),
-                    'non-empty-array<string,int|string>',
+                    'non-empty-array<string, int|string>',
                 ],
         ];
     }
diff --git a/tests/unit/Types/ArrayTest.php b/tests/unit/Types/ArrayTest.php
index 3c567dd..8201f29 100644
--- a/tests/unit/Types/ArrayTest.php
+++ b/tests/unit/Types/ArrayTest.php
@@ -64,7 +64,7 @@ public function provideToStringData(): array
             'array of mixed' => [new Array_(new Mixed_()), 'mixed[]'],
             'array of single type' => [new Array_(new String_()), 'string[]'],
             'array of compound type' => [new Array_(new Compound([new Integer(), new String_()])), '(int|string)[]'],
-            'array with key type' => [new Array_(new String_(), new Integer()), 'array<int,string>'],
+            'array with key type' => [new Array_(new String_(), new Integer()), 'array<int, string>'],
         ];
     }
 }
diff --git a/tests/unit/Types/IterableTest.php b/tests/unit/Types/IterableTest.php
index d43216b..7520ce3 100644
--- a/tests/unit/Types/IterableTest.php
+++ b/tests/unit/Types/IterableTest.php
@@ -38,7 +38,7 @@ public function provideToStringData(): array
                 new Iterable_(new Compound([new Integer(), new String_()])),
                 'iterable<int|string>',
             ],
-            'iterable with key type' => [new Iterable_(new String_(), new Integer()), 'iterable<int,string>'],
+            'iterable with key type' => [new Iterable_(new String_(), new Integer()), 'iterable<int, string>'],
         ];
     }
 }