From 8fbd175b0e5e077c9ca28bb48e7837039916946a Mon Sep 17 00:00:00 2001
From: Simeon Warner <simeon.warner@cornell.edu>
Date: Thu, 12 Dec 2024 13:46:57 -0500
Subject: [PATCH] Tidy layout_nnnn_uuid_quadtree

---
 ocfl/layout_nnnn_uuid_quadtree.py       | 42 +++++++++++++++++++++----
 tests/test_layout_nnnn_uuid_quadtree.py | 19 +++++++++--
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/ocfl/layout_nnnn_uuid_quadtree.py b/ocfl/layout_nnnn_uuid_quadtree.py
index ba1414d..7139738 100644
--- a/ocfl/layout_nnnn_uuid_quadtree.py
+++ b/ocfl/layout_nnnn_uuid_quadtree.py
@@ -29,26 +29,56 @@ def config(self):
     def check_prefix(self, value):
         """Check prefix paremeter.
 
-        Any string is allowed.
+        Argument:
+            value (str): prefix string
+
+        Raises:
+            LayoutException: if the prefix is not allowed
+
+        Any non-empty string is allowed. Sets the prefix property as a side-effect.
         """
         if value is None:
             raise LayoutException("prefix parameter must be specified")
-        if not isinstance(value, str):
-            raise LayoutException("prefix parameter must be a string")
+        if not isinstance(value, str) or value == "":
+            raise LayoutException("prefix parameter must be a non-empty string")
         self.prefix = value
 
     def encode(self, identifier):
-        """NOOP encode identifier."""
+        """NOOP encode identifier.
+
+        Arguments:
+            identifier (str): identifier
+
+        Returns:
+            str: unchanged identifier
+        """
         return identifier
 
     def decode(self, identifier):
-        """NOOP decode identifier."""
+        """NOOP decode identifier.
+
+        Arguments:
+            identifier (str): identifier
+
+        Returns:
+            str: unchanged identifier
+        """
         return identifier
 
     def identifier_to_path(self, identifier):
         """Convert identifier to path relative to root.
 
-        Must match prefix:6ba7b810-9dad-11d1-80b4-00c04fd430c8
+        Argument:
+            identifier (str): object identifier
+
+        Returns:
+            str: object path for this layout
+
+        Raises:
+            LayoutException: if the identifier cannot be converted to a valid
+            object path.
+
+        Format is "prefix:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
         """
         if identifier.startswith(self.prefix):
             identifier = identifier[len(self.prefix):]
diff --git a/tests/test_layout_nnnn_uuid_quadtree.py b/tests/test_layout_nnnn_uuid_quadtree.py
index 9d98a39..a9ba5ec 100644
--- a/tests/test_layout_nnnn_uuid_quadtree.py
+++ b/tests/test_layout_nnnn_uuid_quadtree.py
@@ -1,19 +1,34 @@
 """Digest tests."""
 import unittest
+from ocfl.layout import LayoutException
 from ocfl.layout_nnnn_uuid_quadtree import Layout_NNNN_UUID_Quadtree
 
 
 class TestAll(unittest.TestCase):
     """TestAll class to run tests."""
 
-    def test01_encode(self):
+    def test_config(self):
+        """Test config property."""
+        layout = Layout_NNNN_UUID_Quadtree()
+        self.assertEqual(set(layout.config.keys()), set(("extensionName", "prefix")))
+
+    def test_check_prefix(self):
+        """Test check_prefix method."""
+        layout = Layout_NNNN_UUID_Quadtree()
+        self.assertRaises(LayoutException, layout.check_prefix, None)
+        self.assertRaises(LayoutException, layout.check_prefix, 53)
+        self.assertRaises(LayoutException, layout.check_prefix, "")  # stil not!
+        self.assertEqual(layout.check_prefix("Pref"), None)
+        self.assertEqual(layout.prefix, "Pref")
+
+    def test_encode(self):
         """Test NOOP encode."""
         uuqt = Layout_NNNN_UUID_Quadtree()
         self.assertEqual(uuqt.encode(""), "")
         self.assertEqual(uuqt.encode("a"), "a")
         self.assertEqual(uuqt.encode("a/b:?"), "a/b:?")
 
-    def test02_decode(self):
+    def test_decode(self):
         """Test NOOP decode."""
         uuqt = Layout_NNNN_UUID_Quadtree()
         self.assertEqual(uuqt.decode(""), "")