chore: add tests to test fileExists onto directory and vice-versa

src/AdapterTestUtilities/FilesystemAdapterTestCase.php

@@ -644,6 +644,38 @@ public function moving_a_file(): void
         });
     }
 
+    /**
+     * @test
+     */
+    public function file_exists_on_directory_is_false(): void
+    {
+        $this->runScenario(function () {
+            $adapter = $this->adapter();
+
+            $this->assertFalse($adapter->directoryExists('test'));
+            $adapter->createDirectory('test', new Config());
+
+            $this->assertTrue($adapter->directoryExists('test'));
+            $this->assertFalse($adapter->fileExists('test'));
+        });
+    }
+
+    /**
+     * @test
+     */
+    public function directory_exists_on_file_is_false(): void
+    {
+        $this->runScenario(function () {
+            $adapter = $this->adapter();
+
+            $this->assertFalse($adapter->fileExists('test.txt'));
+            $adapter->write('test.txt', 'content', new Config());
+
+            $this->assertTrue($adapter->fileExists('test.txt'));
+            $this->assertFalse($adapter->directoryExists('test.txt'));
+        });
+    }
+
     /**
      * @test
      */