Add method to update state from progress

This way the method to measure progress calculate only the
statistics and it is easier to test, removing the logic about the
state file, header stats and number of bw lines returned to this
method instead.

sbws/lib/v3bwfile.py

@@ -484,6 +484,7 @@ class V3BWFile(object):
         header = V3BWHeader.from_results(results, state_fpath)
         bw_lines_raw = []
         num_net_relays = cls.read_num_net_relays(consensus_path)
+        state = State(state_fpath)
         for fp, values in results.items():
             # log.debug("Relay fp %s", fp)
             line = V3BWLine.from_results(values, secs_recent, secs_away,
@@ -493,12 +494,8 @@ class V3BWFile(object):
         if not bw_lines_raw:
             log.info("After applying restrictions to the raw results, "
                      "there is not any. Scaling can not be applied.")
-            if num_net_relays is not None:
-                statsd, success = cls.measured_progress_stats(bw_lines_raw,
-                    num_net_relays, state_fpath)
-                if not success:
-                    header.add_stats(**statsd)
-                    bw_lines = []
+            cls.update_progress(cls, bw_lines_raw, header, num_net_relays,
+                                state)
             return cls(header, [])
         if scaling_method == SBWS_SCALING:
             bw_lines = cls.bw_sbws_scale(bw_lines_raw, scale_constant)
@@ -508,14 +505,7 @@ class V3BWFile(object):
             bw_lines = cls.bw_torflow_scale(bw_lines_raw, torflow_obs,
                                             torflow_cap, torflow_round_digs)
             # log.debug(bw_lines[-1])
-            if num_net_relays is not None:
-                statsd, success = cls.measured_progress_stats(bw_lines,
-                    consensus_path, state_fpath)
-                # add statistics about progress only when there are not enough
-                # measured relays. Should some stats be added always?
-                if not success:
-                    header.add_stats(**statsd)
-                    bw_lines = []
+            cls.update_progress(cls, bw_lines, header, num_net_relays, state)
         else:
             bw_lines = cls.bw_kb(bw_lines_raw)
             # log.debug(bw_lines[-1])
@@ -817,7 +807,8 @@ class V3BWFile(object):
         return num
 
     @staticmethod
-    def measured_progress_stats(bw_lines, num_net_relays, state_fpath):
+    def measured_progress_stats(bw_lines, num_net_relays,
+                                min_perc_reached_before):
         """ Statistics about measurements progress,
         to be included in the header.
 
@@ -835,8 +826,6 @@ class V3BWFile(object):
         # measured relays is not either.
         assert isinstance(num_net_relays, int)
         assert isinstance(bw_lines, list)
-        assert isinstance(state_fpath, str)
-        state = State(state_fpath)
         statsd = {}
         statsd['num_measured_relays'] = len(bw_lines)
         statsd['num_net_relays'] = num_net_relays
@@ -846,12 +835,7 @@ class V3BWFile(object):
                                                / statsd['num_net_relays'])
         statsd['perc_measured_targed'] = MIN_REPORT
         if statsd['num_measured_relays'] < statsd['num_target_relays']:
-            # the min percent of measured relays is not reached,
-            # write None in the state file and obtain whether it was reached
-            # before
-            min_perc_reached_before = state.get('min_perc_reached')
-            state['min_perc_reached'] = None
-            # if it was reached before, warn
+            # if min percent was was reached before, warn
             # otherwise, debug
             if min_perc_reached_before is not None:
                 log.warning('The percentage of the measured relays is less '
@@ -862,9 +846,6 @@ class V3BWFile(object):
                          'than the %s%% of the relays in the network (%s).',
                          MIN_REPORT, statsd['num_net_relays'])
             return statsd, False
-        # write in the state file the date the min percent of measured
-        # relays has been reached
-        state['min_perc_reached'] = now_isodt_str()
         return statsd, True
 
     @property
@@ -906,6 +887,21 @@ class V3BWFile(object):
          ['sum_bw', 'mean_bw', 'median_bw', 'num',
           'max_bw', 'min_bw']]
 
+    def update_progress(self, bw_lines, header, num_net_relays, state):
+        min_perc_reached_before = state.get('min_perc_reached')
+        if num_net_relays is not None:
+            statsd, success = self.measured_progress_stats(
+                bw_lines, num_net_relays, min_perc_reached_before)
+            # add statistics about progress only when there are not enough
+            # measured relays. Should some stats be added always?
+            if not success:
+                header.add_stats(**statsd)
+                bw_lines = []
+                state['min_perc_reached'] = None
+            else:
+                state['min_perc_reached'] = now_isodt_str()
+        return bw_lines
+
     def bw_line_for_node_id(self, node_id):
         """Returns the bandwidth line for a given node fingerprint.