test: use f-strings in feature_minchainwork.py

test/functional/feature_minchainwork.py

@@ -45,16 +45,16 @@ class MinimumChainWorkTest(BitcoinTestFramework):
         # Start building a chain on node0.  node2 shouldn't be able to sync until node1's
         # minchainwork is exceeded
         starting_chain_work = REGTEST_WORK_PER_BLOCK # Genesis block's work
-        self.log.info("Testing relay across node %d (minChainWork = %d)", 1, self.node_min_work[1])
+        self.log.info(f"Testing relay across node 1 (minChainWork = {self.node_min_work[1]})")
 
         starting_blockcount = self.nodes[2].getblockcount()
 
         num_blocks_to_generate = int((self.node_min_work[1] - starting_chain_work) / REGTEST_WORK_PER_BLOCK)
-        self.log.info("Generating %d blocks on node0", num_blocks_to_generate)
+        self.log.info(f"Generating {num_blocks_to_generate} blocks on node0")
         hashes = self.nodes[0].generatetoaddress(num_blocks_to_generate,
                                                  self.nodes[0].get_deterministic_priv_key().address)
 
-        self.log.info("Node0 current chain work: %s", self.nodes[0].getblockheader(hashes[-1])['chainwork'])
+        self.log.info(f"Node0 current chain work: {self.nodes[0].getblockheader(hashes[-1])['chainwork']}")
 
         # Sleep a few seconds and verify that node2 didn't get any new blocks
         # or headers.  We sleep, rather than sync_blocks(node0, node1) because
@@ -63,7 +63,7 @@ class MinimumChainWorkTest(BitcoinTestFramework):
         time.sleep(3)
 
         self.log.info("Verifying node 2 has no more blocks than before")
-        self.log.info("Blockcounts: %s", [n.getblockcount() for n in self.nodes])
+        self.log.info(f"Blockcounts: {[n.getblockcount() for n in self.nodes]}")
         # Node2 shouldn't have any new headers yet, because node1 should not
         # have relayed anything.
         assert_equal(len(self.nodes[2].getchaintips()), 1)
@@ -84,7 +84,7 @@ class MinimumChainWorkTest(BitcoinTestFramework):
         # continue the test.
 
         self.sync_all()
-        self.log.info("Blockcounts: %s", [n.getblockcount() for n in self.nodes])
+        self.log.info(f"Blockcounts: {[n.getblockcount() for n in self.nodes]}")
 
 if __name__ == '__main__':
     MinimumChainWorkTest().main()