refactor of python writer; separate pyramid building from i/o

python/test/test_writer.py

@@ -0,0 +1,52 @@
+import unittest
+from pmtiles import Entry
+from pmtiles.writer import find_leaf_level, make_pyramid
+
+class TestTilePyramid(unittest.TestCase):
+    def test_root_sorted(self):
+      entries = [
+        Entry(1,0,0,1,1,False),
+        Entry(1,0,1,2,1,False),
+        Entry(1,1,0,3,1,False),
+        Entry(1,1,1,4,1,False),
+        Entry(0,0,0,0,1,False)
+      ]
+      root_entries, leaf_dirs = make_pyramid(entries,0,6)
+      self.assertEqual(len(root_entries),5)
+      self.assertEqual(len(leaf_dirs),0)
+      self.assertEqual(root_entries[0].z,0)
+      self.assertEqual(root_entries[4].z,1)
+
+    def test_leafdir(self):
+      entries = [
+        Entry(0,0,0,0,1,False),
+        Entry(1,0,0,1,1,False),
+        Entry(1,0,1,2,1,False),
+        Entry(1,1,0,3,1,False),
+        Entry(1,1,1,4,1,False),
+        Entry(2,0,0,5,1,False),
+        Entry(3,0,0,6,1,False),
+        Entry(2,0,1,7,1,False),
+        Entry(3,0,2,8,1,False)
+      ]
+      root_entries, leaf_dirs = make_pyramid(entries,0,7)
+      self.assertEqual(len(root_entries),7)
+      self.assertEqual(len(leaf_dirs),1)
+      self.assertEqual(len(leaf_dirs[0]),4)
+      self.assertEqual(leaf_dirs[0][0].z,2)
+      self.assertEqual(leaf_dirs[0][1].z,2)
+      self.assertEqual(leaf_dirs[0][2].z,3)
+      self.assertEqual(leaf_dirs[0][3].z,3)
+
+    def test_full_z7_pyramid(self):
+      entries = []
+      # create artificial 8 levels  
+      for z in range(0,9):
+        for x in range(0,pow(2,z)):
+          for y in range(0,pow(2,z)):
+            entries.append(Entry(z,x,y,0,0,False))
+      self.assertEqual(find_leaf_level(entries,21845),7)
+      root_entries, leaf_dirs = make_pyramid(entries,0)
+      self.assertEqual(len(root_entries),21845)
+      self.assertEqual(len(leaf_dirs),4)
+      self.assertTrue(len(leaf_dirs[0]) <= 21845)