diff --git a/plugins/OptionalManager/Test/TestOptionalManager.py b/plugins/OptionalManager/Test/TestOptionalManager.py
index a61aa078..ab33dc42 100644
--- a/plugins/OptionalManager/Test/TestOptionalManager.py
+++ b/plugins/OptionalManager/Test/TestOptionalManager.py
@@ -40,3 +40,68 @@ class TestOptionalManager:
         num_optional_files_before = contents.db.execute("SELECT COUNT(*) FROM file_optional").fetchone()[0]
         del contents["content.json"]
         assert contents.db.execute("SELECT COUNT(*) FROM file_optional").fetchone()[0] < num_optional_files_before
+
+    def testVerifyFiles(self, site):
+        contents = site.content_manager.contents
+
+        # Add new file
+        new_content = copy.deepcopy(contents["content.json"])
+        new_content["files_optional"]["testfile"] = {
+            "size": 1234,
+            "sha512": "aaaabbbbcccc"
+        }
+        contents["content.json"] = new_content
+        file_row = contents.db.execute("SELECT * FROM file_optional WHERE inner_path = 'testfile'").fetchone()
+        assert not file_row["is_downloaded"]
+
+        # Write file from outside of ZeroNet
+        site.storage.open("testfile", "wb").write("A" * 1234)  # For quick check hash does not matter only file size
+
+        hashfield_len_before = len(site.content_manager.hashfield)
+        site.storage.verifyFiles(quick_check=True)
+        assert len(site.content_manager.hashfield) == hashfield_len_before + 1
+
+        file_row = contents.db.execute("SELECT * FROM file_optional WHERE inner_path = 'testfile'").fetchone()
+        assert file_row["is_downloaded"]
+
+        # Delete file outside of ZeroNet
+        site.storage.delete("testfile")
+        site.storage.verifyFiles(quick_check=True)
+        file_row = contents.db.execute("SELECT * FROM file_optional WHERE inner_path = 'testfile'").fetchone()
+        assert not file_row["is_downloaded"]
+
+    def testVerifyFilesSameHashId(self, site):
+        contents = site.content_manager.contents
+
+        new_content = copy.deepcopy(contents["content.json"])
+
+        # Add two files with same hashid (first 4 character)
+        new_content["files_optional"]["testfile1"] = {
+            "size": 1234,
+            "sha512": "aaaabbbbcccc"
+        }
+        new_content["files_optional"]["testfile2"] = {
+            "size": 2345,
+            "sha512": "aaaabbbbdddd"
+        }
+        contents["content.json"] = new_content
+
+        assert site.content_manager.hashfield.getHashId("aaaabbbbcccc") == site.content_manager.hashfield.getHashId("aaaabbbbdddd")
+
+        # Write files from outside of ZeroNet (For quick check hash does not matter only file size)
+        site.storage.open("testfile1", "wb").write("A" * 1234)
+        site.storage.open("testfile2", "wb").write("B" * 2345)
+
+        site.storage.verifyFiles(quick_check=True)
+
+        # Make sure that both is downloaded
+        assert site.content_manager.isDownloaded("testfile1")
+        assert site.content_manager.isDownloaded("testfile2")
+        assert site.content_manager.hashfield.getHashId("aaaabbbbcccc") in site.content_manager.hashfield
+
+        # Delete one of the files
+        site.storage.delete("testfile1")
+        site.storage.verifyFiles(quick_check=True)
+        assert not site.content_manager.isDownloaded("testfile1")
+        assert site.content_manager.isDownloaded("testfile2")
+        assert site.content_manager.hashfield.getHashId("aaaabbbbdddd") in site.content_manager.hashfield