rio-pmtiles python package [#338] (#542)

Add rio-pmtiles command line tool. [#338]

This is derived from the original mapbox/rio-mbtiles implementation, with changes:

* output PMTiles only instead of MBTiles.
* Python 3.7+ only.
* remove --implementation, --image-dump, --append/--overwrite, --covers features.
* bump dependency versions.
* better progress reporting; add pyroaring. 
* update README and license texts.
* rio-pmtiles v0.0.6 on PyPI

python/pmtiles/test/test_reader_writer.py

@@ -0,0 +1,70 @@
+import unittest
+from io import BytesIO
+from pmtiles.writer import Writer
+from pmtiles.reader import all_tiles, 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)
+
+    def test_all_tiles(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"1")
+        writer.write_tile(zxy_to_tileid(2, 0, 0), b"2")
+        writer.finalize(
+            {
+                "tile_compression": Compression.UNKNOWN,
+                "tile_type": TileType.UNKNOWN,
+            },
+            {"key": "value"},
+        )
+
+        reader = Reader(MemorySource(buf.getvalue()))
+        tiles = list(all_tiles(reader.get_bytes))
+        self.assertEqual(tiles, [
+            ((0,0,0), b"1"),
+            ((1,0,0), b"1"),
+            ((2,0,0), b"2"),
+        ])