add multi column non unique columns

tests/test_meta_constraints/test_index_constraints.py

@@ -0,0 +1,68 @@
+import asyncpg  # type: ignore
+import databases
+import pytest
+import sqlalchemy
+
+import ormar.fields.constraints
+from tests.settings import DATABASE_URL
+
+database = databases.Database(DATABASE_URL, force_rollback=True)
+metadata = sqlalchemy.MetaData()
+
+
+class Product(ormar.Model):
+    class Meta:
+        tablename = "products"
+        metadata = metadata
+        database = database
+        constraints = [
+            ormar.fields.constraints.IndexColumns("company", "name", name="my_index"),
+            ormar.fields.constraints.IndexColumns("location", "company_type"),
+        ]
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    company: str = ormar.String(max_length=200)
+    location: str = ormar.String(max_length=200)
+    company_type: str = ormar.String(max_length=200)
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    engine = sqlalchemy.create_engine(DATABASE_URL)
+    metadata.drop_all(engine)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+def test_table_structure():
+    assert len(Product.Meta.table.indexes) > 0
+    indexes = sorted(
+        list(Product.Meta.table.indexes), key=lambda x: x.name, reverse=True
+    )
+    test_index = indexes[0]
+    assert test_index.name == "my_index"
+    assert [col.name for col in test_index.columns] == ["company", "name"]
+
+    test_index = indexes[1]
+    assert test_index.name == "ix_products_location_company_type"
+    assert [col.name for col in test_index.columns] == ["location", "company_type"]
+
+
+@pytest.mark.asyncio
+async def test_index_is_not_unique():
+    async with database:
+        async with database.transaction(force_rollback=True):
+            await Product.objects.create(
+                name="Cookies", company="Nestle", location="A", company_type="B"
+            )
+            await Product.objects.create(
+                name="Mars", company="Mars", location="B", company_type="Z"
+            )
+            await Product.objects.create(
+                name="Mars", company="Nestle", location="C", company_type="X"
+            )
+            await Product.objects.create(
+                name="Mars", company="Mars", location="D", company_type="Y"
+            )