Resolve relative on relative

src/AbstractPath.php

@@ -37,7 +37,7 @@ abstract class AbstractPath implements PathInterface
     /**
      * @return static
      */
-    private function doResolveRelative(RelativePath $path, bool $strict): self
+    protected function doResolveRelative(RelativePath $path, bool $strict): self
     {
         $relativeComponents = $path->components;
 
@@ -56,7 +56,12 @@ abstract class AbstractPath implements PathInterface
                 continue;
             }
 
-            if ($relativeComponents[$i] === '..') {
+            if (
+                $relativeComponents[$i] === '..' &&
+                !$components->isEmpty() &&
+                $components->top() !== '..' &&
+                $components->top() !== '.'
+            ) {
                 $components->pop();
                 continue;
             }

src/RelativePath.php

@@ -76,4 +76,24 @@ final class RelativePath extends AbstractPath
 
         return $path;
     }
+
+    protected function normalizeHead(\SplDoublyLinkedList $components, bool $strict): \SplDoublyLinkedList
+    {
+        if ($this->isRoot()) {
+            return parent::normalizeHead($components, $strict);
+        }
+
+        while (!$components->isEmpty()) {
+            if ($components[0] === '.') {
+                $components->shift();
+                continue;
+            }
+
+            break;
+        }
+
+        $components->unshift('.');
+
+        return $components;
+    }
 }

tests/RelativePathTest.php

@@ -54,7 +54,7 @@ class RelativePathTest extends TestCase
                 '/i/am/test/path',
                 '/i/am/test/path/i/am/test/path',
                 '/i/am/i/am/test/path',
-                null
+                '/i/am/test/path',
             ],
             [
                 '/i/am/test/path',
@@ -66,7 +66,7 @@ class RelativePathTest extends TestCase
                 '/i/am/test/path',
                 '../../i/am/test/path/i/am/test/path',
                 '../../i/am/i/am/test/path',
-                '../../../../../../i/am/test/path'
+                '../../../../../../i/am/test/path',
             ],
             [
                 '/i/am/test/path',
@@ -80,11 +80,6 @@ class RelativePathTest extends TestCase
             foreach ($relativePaths as $rpi => $rp) {
                 $matrixResult = $matrix[$pi][$rpi];
 
-                if ($matrixResult === null) {
-                    // TODO: should throw
-                    continue;
-                }
-
                 self::assertEquals($matrixResult, $p->resolveRelative($rp)->toString());
             }
         }