test: add system test for decimal numeric support (#630)

* fix: lint_setup_py was failing in Kokoro is not fixed

* feat: add decimal/numeric support

* fix: remove validation for decimal field not supported

* feat: updated decimal support error message in spanner to match error thrown by python spanner decimal/numeric validation

* fix: removed test_validation as decimal support is now added so validation is not required

* refactor: removed unused settings and conftest file from system tests folder

* fix: corrected the error msg thrown by numeric value not supported error

Author: vi3k6i5

tests/system/django_spanner/models.py

@@ -14,3 +14,10 @@ class Author(models.Model):
     first_name = models.CharField(max_length=20)
     last_name = models.CharField(max_length=20)
     rating = models.DecimalField()
+
+
+class Number(models.Model):
+    num = models.DecimalField()
+
+    def __str__(self):
+        return str(self.num)

tests/system/django_spanner/test_decimal.py

@@ -0,0 +1,117 @@
+# Copyright 2021 Google LLC
+#
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+from .models import Author, Number
+from django.test import TransactionTestCase
+from django.db import connection, ProgrammingError
+from django.db.utils import IntegrityError
+from decimal import Decimal
+from tests.system.django_spanner.utils import (
+    setup_instance,
+    teardown_instance,
+    setup_database,
+    teardown_database,
+    USE_EMULATOR,
+)
+
+
+class TestDecimal(TransactionTestCase):
+    @classmethod
+    def setUpClass(cls):
+        setup_instance()
+        setup_database()
+        with connection.schema_editor() as editor:
+            # Create the tables
+            editor.create_model(Author)
+            editor.create_model(Number)
+
+    @classmethod
+    def tearDownClass(cls):
+        with connection.schema_editor() as editor:
+            # delete the table
+            editor.delete_model(Author)
+            editor.delete_model(Number)
+        teardown_database()
+        teardown_instance()
+
+    def rating_transform(self, value):
+        return value["rating"]
+
+    def values_transform(self, value):
+        return value.num
+
+    def assertValuesEqual(
+        self, queryset, expected_values, transformer, ordered=True
+    ):
+        self.assertQuerysetEqual(
+            queryset, expected_values, transformer, ordered
+        )
+
+    def test_insert_and_search_decimal_value(self):
+        """
+        Tests model object creation with Author model.
+        """
+        author_kent = Author(
+            first_name="Arthur", last_name="Kent", rating=Decimal("4.1"),
+        )
+        author_kent.save()
+        qs1 = Author.objects.filter(rating__gte=3).values("rating")
+        self.assertValuesEqual(
+            qs1, [Decimal("4.1")], self.rating_transform,
+        )
+        # Delete data from Author table.
+        Author.objects.all().delete()
+
+    def test_decimal_filter(self):
+        """
+        Tests decimal filter query.
+        """
+        # Insert data into Number table.
+        Number.objects.bulk_create(
+            Number(num=Decimal(i) / Decimal(10)) for i in range(10)
+        )
+        qs1 = Number.objects.filter(num__lte=Decimal(2) / Decimal(10))
+        self.assertValuesEqual(
+            qs1,
+            [Decimal(i) / Decimal(10) for i in range(3)],
+            self.values_transform,
+            ordered=False,
+        )
+        # Delete data from Number table.
+        Number.objects.all().delete()
+
+    def test_decimal_precision_limit(self):
+        """
+        Tests decimal object precission limit.
+        """
+        num_val = Number(num=Decimal(1) / Decimal(3))
+        if USE_EMULATOR:
+            msg = "The NUMERIC type supports 38 digits of precision and 9 digits of scale."
+            with self.assertRaisesRegex(IntegrityError, msg):
+                num_val.save()
+        else:
+            msg = "400 Invalid value for bind parameter a0: Expected NUMERIC."
+            with self.assertRaisesRegex(ProgrammingError, msg):
+                num_val.save()
+
+    def test_decimal_update(self):
+        """
+        Tests decimal object update.
+        """
+        author_kent = Author(
+            first_name="Arthur", last_name="Kent", rating=Decimal("4.1"),
+        )
+        author_kent.save()
+        author_kent.rating = Decimal("4.2")
+        author_kent.save()
+        qs1 = Author.objects.filter(rating__gte=Decimal("4.2")).values(
+            "rating"
+        )
+        self.assertValuesEqual(
+            qs1, [Decimal("4.2")], self.rating_transform,
+        )
+        # Delete data from Author table.
+        Author.objects.all().delete()