BigQuery: Add TestReference class. Add table function to DatasetRefer…

…ence (#3942)

bigquery/google/cloud/bigquery/dataset.py

@@ -19,6 +19,7 @@
 from google.cloud._helpers import _datetime_from_microseconds
 from google.cloud.exceptions import NotFound
 from google.cloud.bigquery.table import Table
+from google.cloud.bigquery.table import TableReference
 
 
 class AccessEntry(object):
@@ -126,6 +127,14 @@ def dataset_id(self):
         """
         return self._dataset_id
 
+    def table(self, table_id):
+        """Constructs a TableReference.
+
+        :rtype: :class:`google.cloud.bigquery.table.TableReference`
+        :returns: a TableReference for a table in this dataset.
+        """
+        return TableReference(self, table_id)
+
 
 class Dataset(object):
     """Datasets are containers for tables.

bigquery/google/cloud/bigquery/table.py

@@ -48,6 +48,42 @@
 _DEFAULT_NUM_RETRIES = 6
 
 
+class TableReference(object):
+    """TableReferences are pointers to tables.
+
+    See
+    https://cloud.google.com/bigquery/docs/reference/rest/v2/tables
+
+    :type dataset_ref: :class:`google.cloud.bigquery.dataset.DatasetReference`
+    :param dataset_ref: a pointer to the dataset
+
+    :type table_id: str
+    :param table_id: the ID of the table
+    """
+
+    def __init__(self, dataset_ref, table_id):
+        self._dataset_ref = dataset_ref
+        self._table_id = table_id
+
+    @property
+    def dataset_ref(self):
+        """Pointer to the dataset.
+
+        :rtype: :class:`google.cloud.bigquery.dataset.DatasetReference`
+        :returns: a pointer to the dataset.
+        """
+        return self._dataset_ref
+
+    @property
+    def table_id(self):
+        """Table ID.
+
+        :rtype: str
+        :returns: the table ID.
+        """
+        return self._table_id
+
+
 class Table(object):
     """Tables represent a set of rows whose values correspond to a schema.
 

bigquery/tests/unit/test_dataset.py

@@ -101,6 +101,12 @@ def test_ctor_defaults(self):
         self.assertEqual(dataset_ref.project_id, 'some-project-1')
         self.assertEqual(dataset_ref.dataset_id, 'dataset_1')
 
+    def test_table(self):
+        dataset_ref = self._make_one('some-project-1', 'dataset_1')
+        table_ref = dataset_ref.table('table_1')
+        self.assertIs(table_ref.dataset_ref, dataset_ref)
+        self.assertEqual(table_ref.table_id, 'table_1')
+
 
 class TestDataset(unittest.TestCase):
     PROJECT = 'project'

bigquery/tests/unit/test_table.py

@@ -37,6 +37,26 @@ def _verifySchema(self, schema, resource):
             self._verify_field(field, r_field)
 
 
+class TestTableReference(unittest.TestCase):
+
+    @staticmethod
+    def _get_target_class():
+        from google.cloud.bigquery.table import TableReference
+
+        return TableReference
+
+    def _make_one(self, *args, **kw):
+        return self._get_target_class()(*args, **kw)
+
+    def test_ctor_defaults(self):
+        from google.cloud.bigquery.dataset import DatasetReference
+        dataset_ref = DatasetReference('project_1', 'dataset_1')
+
+        table_ref = self._make_one(dataset_ref, 'table_1')
+        self.assertIs(table_ref.dataset_ref, dataset_ref)
+        self.assertEqual(table_ref.table_id, 'table_1')
+
+
 class TestTable(unittest.TestCase, _SchemaBase):
 
     PROJECT = 'prahj-ekt'