Readme and attempt to fix delete dataset in tests.

README.md

@@ -93,13 +93,16 @@ res = dask_bigquery.to_gbq(
 With explicit credentials:
 
 ```python
+import dask
+import dask_bigquery
 from google.oauth2.service_account import Credentials
 
+ddf = dask.datasets.timeseries(freq="1min")
+
 # credentials
-creds_dict = {"type": ..., "project_id": ..., "private_key_id": ...}
-credentials = Credentials.from_service_account_info(info=creds_dict)
+credentials = Credentials.from_service_account_file("/home/<username>/google.json")
 
-res = to_gbq(
+res = dask_bigquery.to_gbq(
     ddf,
     project_id="my_project_id",
     dataset_id="my_dataset_id",

dask_bigquery/tests/test_core.py

@@ -50,10 +50,7 @@ def dataset():
 
         yield dataset
 
-        bq_client.delete_dataset(
-            dataset=f"{project_id}.{dataset_id}",
-            delete_contents=True,
-        )
+        bq_client.delete_dataset(dataset=dataset, delete_contents=True)
 
 
 @pytest.fixture(scope="module")
@@ -79,7 +76,7 @@ def table(dataset, df):
         )  # Make an API request.
         job.result()
 
-    yield (project_id, dataset_id, table_id)
+    yield project_id, dataset_id, table_id
 
 
 @pytest.fixture(scope="module")
@@ -109,7 +106,7 @@ def required_partition_filter_table(dataset, df):
         table.require_partition_filter = True
         bq_client.update_table(table, ["require_partition_filter"])
 
-    yield (project_id, dataset_id, table_id)
+    yield project_id, dataset_id, table_id
 
 
 @pytest.fixture