Start adding API for parallel execution

Added run_multiple_commands method inside the SUT parent class. This API
is needed to start working on parallel execution.

Author: acerv

ltp/sut.py

@@ -134,7 +134,9 @@ def stop(self, timeout: float = 30, iobuffer: IOBuffer = None) -> None:
         """
         raise NotImplementedError()
 
-    def force_stop(self, timeout: float = 30, iobuffer: IOBuffer = None) -> None:
+    def force_stop(self,
+                   timeout: float = 30,
+                   iobuffer: IOBuffer = None) -> None:
         """
         Force stopping the current SUT session.
         :param timeout: timeout to complete in seconds
@@ -151,6 +153,7 @@ def run_command(self,
         """
         Run command on target.
         :param command: command to execute
+        :type command: str
         :param timeout: timeout before stopping execution. Default is 3600
         :type timeout: float
         :param iobuffer: buffer used to write SUT stdout
@@ -169,6 +172,39 @@ def run_command(self,
         """
         raise NotImplementedError()
 
+    def run_multiple_commands(self,
+                              commands: list,
+                              timeout: float = 3600,
+                              command_completed: callable = None) -> list:
+        """
+        Run multiple commands in parallel on target.
+        :param commands: commands to execute
+        :type commands: list(str)
+        :param timeout: timeout before stopping execution. Default is 3600
+        :type timeout: float
+        :param command_completed: function called when a test has completed.
+            Its definition is `command_completed(ret: set)` where ret has the
+            same definition of data returned by `run_multiple_commands` inside
+            the list.
+        :type command_completed: callable
+        :returns: list of (dict, Exception) containing command execution
+            information and exception.
+
+            [
+                ({
+                    "command": <str>,
+                    "timeout": <float>,
+                    "returncode": <int>,
+                    "stdout": <str>,
+                    "exec_time": <float>,
+                }, None)
+                ...
+            ]
+
+            If None is returned, then callback failed.
+        """
+        raise NotImplementedError()
+
     def fetch_file(
             self,
             target_path: str,