Run unit tests across different database backends + fix bugs

docs/api-json-rpc.markdown

@@ -608,7 +608,7 @@ Response example:
 - Purpose: **Get all available tasks**
 - Parameters:
     - **project_id** (integer, required)
-    - **status**: List of status id, the value 1 for active tasks and 0 for inactive (list, required)
+    - **status**: The value 1 for active tasks and 0 for inactive (integer, required)
 - Result on success: **List of tasks**
 - Result on failure: **false**
 
@@ -621,9 +621,7 @@ Request example to fetch all tasks on the board:
     "id": 133280317,
     "params": {
         "project_id": 1,
-        "status": [
-            1
-        ]
+        "status": 1
     }
 }
 ```