Agate less aggressive inference (#861)

CHANGELOG.md

@@ -6,6 +6,7 @@
 - Add a 'generated_at' field to both the manifest and the catalog. ([#887](https://github.com/fishtown-analytics/dbt/pull/877))
 - Version 2 of schema.yml, which allows users to create table and column comments that end up in the manifest ([#880](https://github.com/fishtown-analytics/dbt/pull/880))
 - Add `docs` blocks that users can put into `.md` files and `doc()` value for schema v2 description fields ([#888](https://github.com/fishtown-analytics/dbt/pull/888))
+- Type inference for interpreting CSV data is now less aggressive
 
 ## dbt 0.10.2 (unreleased, codename: Betsy Ross)
 

dbt/clients/agate_helper.py

@@ -2,11 +2,14 @@
 import agate
 
 DEFAULT_TYPE_TESTER = agate.TypeTester(types=[
-    agate.data_types.Number(),
-    agate.data_types.Date(),
-    agate.data_types.DateTime(),
-    agate.data_types.Boolean(),
-    agate.data_types.Text()
+    agate.data_types.Boolean(true_values=('true',),
+                             false_values=('false',),
+                             null_values=('null',)),
+    agate.data_types.Number(null_values=('null',)),
+    agate.data_types.TimeDelta(null_values=('null',)),
+    agate.data_types.Date(null_values=('null',)),
+    agate.data_types.DateTime(null_values=('null',)),
+    agate.data_types.Text(null_values=('null',))
 ])
 
 

test/unit/test_agate_helper.py

@@ -0,0 +1,55 @@
+from __future__ import unicode_literals
+import unittest
+
+from datetime import datetime
+from decimal import Decimal
+from isodate import tzinfo
+import os
+from shutil import rmtree
+from tempfile import mkdtemp
+from dbt.clients import agate_helper
+
+SAMPLE_CSV_DATA = """a,b,c,d,e,f,g
+1,n,test,3.2,20180806T11:33:29.320Z,True,NULL
+2,y,asdf,900,20180806T11:35:29.320Z,False,a string"""
+
+
+EXPECTED = [
+    [1, 'n', 'test', Decimal('3.2'),
+     datetime(2018, 8, 6, 11, 33, 29, 320000, tzinfo=tzinfo.Utc()),
+     True, None,
+    ],
+    [2, 'y', 'asdf', 900,
+     datetime(2018, 8, 6, 11, 35, 29, 320000, tzinfo=tzinfo.Utc()),
+     False, 'a string',
+    ],
+]
+
+class TestAgateHelper(unittest.TestCase):
+    def setUp(self):
+        self.tempdir = mkdtemp()
+
+    def tearDown(self):
+        rmtree(self.tempdir)
+
+    def test_from_csv(self):
+        path = os.path.join(self.tempdir, 'input.csv')
+        with open(path, 'wb') as fp:
+            fp.write(SAMPLE_CSV_DATA.encode('utf-8'))
+        tbl = agate_helper.from_csv(path)
+        self.assertEqual(len(tbl), len(EXPECTED))
+        for idx, row in enumerate(tbl):
+            self.assertEqual(list(row), EXPECTED[idx])
+
+    def test_from_data(self):
+        column_names = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
+        data = [
+            {'a': '1', 'b': 'n', 'c': 'test', 'd': '3.2',
+             'e': '20180806T11:33:29.320Z', 'f': 'True', 'g': 'NULL'},
+            {'a': '2', 'b': 'y', 'c': 'asdf', 'd': '900',
+             'e': '20180806T11:35:29.320Z', 'f': 'False', 'g': 'a string'}
+        ]
+        tbl = agate_helper.table_from_data(data, column_names)
+        self.assertEqual(len(tbl), len(EXPECTED))
+        for idx, row in enumerate(tbl):
+            self.assertEqual(list(row), EXPECTED[idx])