Fix Roserade's Central Kalos dex number and add tests

Roserade and Roselia were mistakenly sharing dex number 72. Presumably
an error from the original X/Y spreadsheet. I guess we never reripped
these after 3DS rom dumping became possible.

Regardless of how it happened, add a test and some database constraints
to ensure that it doesn't happen again.

- Add a test for gaps in pokedex numbers

- Add uniqueness constraints to pokemon_dex_numbers.  A species can
  only appear once per pokedex, and a number cannot be used more than
  once per pokedex.

pokedex/data/csv/pokemon_dex_numbers.csv

@@ -3084,7 +3084,7 @@ species_id,pokedex_id,pokedex_number
 407,5,27
 407,6,27
 407,9,135
-407,12,72
+407,12,73
 407,15,99
 408,1,408
 408,5,36

pokedex/db/tables.py

@@ -1771,6 +1771,13 @@ class PokemonDexNumber(TableBase):
     pokedex_number = Column(Integer, nullable=False,
         doc=u"Number of the Pokémon in that the Pokédex")
 
+    __table_args__ = (
+        UniqueConstraint(pokedex_id, pokedex_number),
+        UniqueConstraint(pokedex_id, species_id),
+        {},
+    )
+
+
 class PokemonEggGroup(TableBase):
     u"""Maps an Egg group to a species; each species belongs to one or two egg groups."""
     __tablename__ = 'pokemon_egg_groups'

pokedex/tests/test_database_sanity.py

@@ -1,6 +1,7 @@
 import pytest
 parametrize = pytest.mark.parametrize
 
+from collections import Counter
 import re
 
 from sqlalchemy.orm import aliased, joinedload, lazyload
@@ -69,7 +70,7 @@ def test_nonzero_autoincrement_ids(session, cls):
         pytest.fail("No zero id in %s" % cls.__name__)
 
 def test_unique_form_order(session):
-    """Check that tone PokemonForm.order value isn't used for more species"""
+    """Check that one PokemonForm.order value isn't used for more species"""
 
     species_by_form_order = {}
 
@@ -88,6 +89,22 @@ def test_unique_form_order(session):
                         species_by_form_order[form.order].name,
                         form.species.name))
 
+def test_pokedex_numbers(session):
+    """Check that pokedex numbers are contiguous (there are no gaps)"""
+
+    dex_query = session.query(tables.Pokedex).order_by(tables.Pokedex.id)
+    failed = False
+    for dex in dex_query:
+        query = session.query(tables.PokemonDexNumber.pokedex_number).filter_by(pokedex_id=dex.id)
+        numbers = set([x[0] for x in query.all()])
+        for i in range(1, max(numbers)):
+            if i not in numbers:
+                print("number {n} is missing from the {dex.name} pokedex".format(n=i, dex=dex))
+                failed = True
+
+    assert not failed, "missing pokedex numbers"
+
+
 def test_default_forms(session):
     """Check that each pokemon has one default form and each species has one
     default pokemon."""