modified the order from desc to asc and add the min-issue in th test

Author: zhuoran-Cheng16

integrations/acquisition/covidcast/test_covidcast_meta_caching.py

@@ -102,6 +102,7 @@ def test_caching(self):
         'mean_value': 1,
         'stdev_value': 0,
         'max_issue': 20200423,
+        'min_issue': 20200422,
         'min_lag': 0,
         'max_lag': 1,
       }

src/acquisition/covidcast/database.py

@@ -300,6 +300,7 @@ def compute_covidcast_meta(self, table_name='covidcast', use_index=True):
         `geo_type` ASC
       
       UNION
+
       SELECT
         `time_type`,
         `geo_type`.
@@ -313,8 +314,8 @@ def compute_covidcast_meta(self, table_name='covidcast', use_index=True):
         `time_type`,
         `geo_type`
       ORDER BY
-        `time_type` DESC,
-        `geo_type`  DESC
+        `time_type` ASC,
+        `geo_type`  ASC
       '''
 
     meta = []