Merge #12806: qa: Fix function names in feature_blocksdir

d71bedb qa: Fix function names in feature_blocksdir (MarcoFalke)

Pull request description:

  This fixes the test failure on master:

  ```
  AttributeError: 'BlocksdirTest' object has no attribute 'assert_start_raises_init_error'
  ```

Tree-SHA512: d96a9b707a9b4fb8752b15f28dae02c60c25cbec21dca5f3ee62e2717c6a49951533c24b52ed0d6e99c5a964ef2c3e90fdc58a9104122714ae9874e121955df6

test/functional/feature_blocksdir.py

@@ -5,10 +5,12 @@
 """Test the blocksdir option.
 """
 
+import os
+import re
+import shutil
+
 from test_framework.test_framework import BitcoinTestFramework, initialize_datadir
 
-import shutil
-import os
 
 class BlocksdirTest(BitcoinTestFramework):
     def set_test_params(self):
@@ -17,18 +19,19 @@ class BlocksdirTest(BitcoinTestFramework):
 
     def run_test(self):
         self.stop_node(0)
-        node0path = os.path.join(self.options.tmpdir, "node0")
-        shutil.rmtree(node0path)
+        shutil.rmtree(self.nodes[0].datadir)
         initialize_datadir(self.options.tmpdir, 0)
         self.log.info("Starting with non exiting blocksdir ...")
-        self.assert_start_raises_init_error(0, ["-blocksdir="+self.options.tmpdir+ "/blocksdir"], "Specified blocks director")
-        os.mkdir(self.options.tmpdir+ "/blocksdir")
+        blocksdir_path = os.path.join(self.options.tmpdir, 'blocksdir')
+        self.nodes[0].assert_start_raises_init_error(["-blocksdir=" + blocksdir_path], re.escape('Error: Specified blocks directory "{}" does not exist.'.format(blocksdir_path)))
+        os.mkdir(blocksdir_path)
         self.log.info("Starting with exiting blocksdir ...")
-        self.start_node(0, ["-blocksdir="+self.options.tmpdir+ "/blocksdir"])
+        self.start_node(0, ["-blocksdir=" + blocksdir_path])
         self.log.info("mining blocks..")
         self.nodes[0].generate(10)
-        assert(os.path.isfile(os.path.join(self.options.tmpdir, "blocksdir", "regtest", "blocks", "blk00000.dat")))
-        assert(os.path.isdir(os.path.join(self.options.tmpdir, "node0", "regtest", "blocks", "index")))
+        assert os.path.isfile(os.path.join(blocksdir_path, "regtest", "blocks", "blk00000.dat"))
+        assert os.path.isdir(os.path.join(self.nodes[0].datadir, "regtest", "blocks", "index"))
+
 
 if __name__ == '__main__':
     BlocksdirTest().main()