Add a minimal bwfile network with V3BandwidthsFile /tmp/bwfile

Closes 26801.

README

@@ -118,6 +118,13 @@ HS Connection Tests:
   # Default behavior is one client connects to each HS
   ./chutney stop networks/hs-025
 
+Bandwidth File Tests:
+  ./tools/test-network.sh --flavour bwfile
+  # Warning: Can't open bandwidth file at configured location: /tmp/bwfile
+  # Create a bwfile with no bandwidths, that is valid for a few days
+  date +%s > /tmp/bwfile
+  ./tools/test-network.sh --flavour bwfile
+
 Waiting for the network:
 
   The tools/test-network.sh script waits CHUTNEY_START_TIME seconds

networks/bwfile

+# By default, Authorities are not configured as exits
+Authority = Node(tag="a", authority=1, relay=1, torrc="authority-bwfile.tmpl")
+ExitRelay = Node(tag="r", relay=1, exit=1, torrc="relay.tmpl")
+Client = Node(tag="c", client=1, torrc="client.tmpl")
+
+# The minimum number of authorities/relays/exits is 3, the minimum path length
+NODES = Authority.getN(2) + ExitRelay.getN(1) + Client.getN(1)
+
+ConfigureNodes(NODES)

torrc_templates/authority-bwfile.tmpl

+${include:authority.tmpl}
+V3BandwidthsFile /tmp/bwfile