diff --git a/tests/Gitonomy/Git/Tests/BlobTest.php b/tests/Gitonomy/Git/Tests/BlobTest.php
index 9c6fa44..5673e78 100644
--- a/tests/Gitonomy/Git/Tests/BlobTest.php
+++ b/tests/Gitonomy/Git/Tests/BlobTest.php
@@ -39,6 +39,21 @@ public function testGetContent(Repository $repository): void
         $this->assertStringContainsString(self::README_FRAGMENT, $blob->getContent());
     }
 
+    #[DataProvider('provideFoobar')]
+    public function testGetContentSiblingToSubmodule(Repository $repository): void
+    {
+        // Regression test for https://github.com/gitonomy/gitlib/issues/12:
+        // a submodule entry in a tree used to break parsing of that tree,
+        // making sibling blobs unreadable.
+        $tree = $repository->getCommit(self::NO_MESSAGE_COMMIT)->getTree();
+
+        $this->assertNotEmpty($tree->getCommitReferenceEntries(), 'Tree contains a submodule entry');
+
+        $blob = $tree->resolvePath('README.md');
+
+        $this->assertStringContainsString(self::README_FRAGMENT, $blob->getContent());
+    }
+
     #[DataProvider('provideFoobar')]
     public function testNotExisting(Repository $repository): void
     {