python writer improvements

* flesh out roundtrip test case
* detect unordered tile writes and set clustered flag appropriately [#115]

python/test/test_reader_writer.py

@@ -0,0 +1,48 @@
+import unittest
+from io import BytesIO
+from pmtiles.writer import Writer
+from pmtiles.reader import Reader, MemorySource
+from pmtiles.tile import Compression, TileType, tileid_to_zxy, zxy_to_tileid
+
+
+class TestReaderWriter(unittest.TestCase):
+    def test_roundtrip(self):
+        buf = BytesIO()
+        writer = Writer(buf)
+        writer.write_tile(zxy_to_tileid(0, 0, 0), b"1")
+        writer.write_tile(zxy_to_tileid(1, 0, 0), b"2")
+        writer.write_tile(zxy_to_tileid(2, 0, 0), b"3")
+        writer.finalize(
+            {
+                "tile_compression": Compression.UNKNOWN,
+                "tile_type": TileType.UNKNOWN,
+            },
+            {"key": "value"},
+        )
+
+        reader = Reader(MemorySource(buf.getvalue()))
+        self.assertEqual(reader.header()["version"], 3)
+        self.assertEqual(reader.header()["min_zoom"], 0)
+        self.assertEqual(reader.header()["max_zoom"], 2)
+        self.assertEqual(reader.header()["clustered"], True)
+        self.assertEqual(reader.metadata()["key"], "value")
+        self.assertEqual(reader.get(0, 0, 0), b"1")
+        self.assertEqual(reader.get(1, 0, 0), b"2")
+        self.assertEqual(reader.get(2, 0, 0), b"3")
+        self.assertEqual(reader.get(3, 0, 0), None)
+
+    def test_roundtrip_unclustered(self):
+        buf = BytesIO()
+        writer = Writer(buf)
+        writer.write_tile(zxy_to_tileid(1, 0, 0), b"2")
+        writer.write_tile(zxy_to_tileid(0, 0, 0), b"1")
+        writer.finalize(
+            {
+                "tile_compression": Compression.UNKNOWN,
+                "tile_type": TileType.UNKNOWN,
+            },
+            {},
+        )
+
+        reader = Reader(MemorySource(buf.getvalue()))
+        self.assertEqual(reader.header()["clustered"], False)