Merge #14903: tests: Handle ImportError explicitly, improve comparisons against None

c9ba253f4f5d675d7736d24c1167229d0898ef1a Add E711 to flake8 check (Daniel Ingram)
17b55202dae8d6e21d2490de89b345c55f7694c0 Compare to None with is/is not (Daniel Ingram)
1b89074ae27ce123adbeed57343deaef13c14f81 Change '== None' to 'is None' (Daniel Ingram)
16d293772365d57cc1a279d5ad0fa6f44b12ed54 Handle exception as ImportError (Daniel Ingram)

Pull request description:

Tree-SHA512: aa5875ea3d9ac47ac898545ff023b511042cd377ea0c4594074daae119f3d4f3fc295721aad94a732a907086ecb32bce19a8eed38adf479f12663c4e8944f721

contrib/devtools/clang-format-diff.py

@@ -109,7 +109,7 @@ def main():
     match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
     if match:
       filename = match.group(2)
-    if filename == None:
+    if filename is None:
       continue
 
     if args.regex is not None:

contrib/devtools/copyright_header.py

@@ -482,7 +482,7 @@ def get_git_change_year_range(filename):
 
 def file_already_has_core_copyright(file_lines):
     index, _ = get_updatable_copyright_line(file_lines)
-    return index != None
+    return index is not None
 
 ################################################################################
 # insert header execution

contrib/devtools/update-translations.py

@@ -130,13 +130,13 @@ def escape_cdata(text):
     return text
 
 def contains_bitcoin_addr(text, errors):
-    if text != None and ADDRESS_REGEXP.search(text) != None:
+    if text is not None and ADDRESS_REGEXP.search(text) is not None:
         errors.append('Translation "%s" contains a bitcoin address. This will be removed.' % (text))
         return True
     return False
 
 def contains_dash_addr(text, errors):
-    if text != None and ADDRESS_REGEXP_DASH.search(text) != None:
+    if text is not None and ADDRESS_REGEXP_DASH.search(text) is not None:
         errors.append('Translation "%s" contains a Dash address. This will be removed.' % (text))
         return True
     return False

test/functional/interface_http.py

@@ -31,13 +31,13 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1
-        assert conn.sock!=None  #according to http/1.1 connection must still be open!
+        assert conn.sock is not None  #according to http/1.1 connection must still be open!
 
         #send 2nd request without closing connection
         conn.request('POST', '/', '{"method": "getchaintips"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1  #must also response with a correct json-rpc message
-        assert conn.sock!=None  #according to http/1.1 connection must still be open!
+        assert conn.sock is not None  #according to http/1.1 connection must still be open!
         conn.close()
 
         #same should be if we add keep-alive because this should be the std. behaviour
@@ -48,13 +48,13 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1
-        assert conn.sock!=None  #according to http/1.1 connection must still be open!
+        assert conn.sock is not None  #according to http/1.1 connection must still be open!
 
         #send 2nd request without closing connection
         conn.request('POST', '/', '{"method": "getchaintips"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1  #must also response with a correct json-rpc message
-        assert conn.sock!=None  #according to http/1.1 connection must still be open!
+        assert conn.sock is not None  #according to http/1.1 connection must still be open!
         conn.close()
 
         #now do the same with "Connection: close"
@@ -65,7 +65,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1
-        assert conn.sock==None  #now the connection must be closed after the response
+        assert conn.sock is None  #now the connection must be closed after the response
 
         #node1 (2nd node) is running with disabled keep-alive option
         urlNode1 = urllib.parse.urlparse(self.nodes[1].url)
@@ -88,7 +88,7 @@ class HTTPBasicsTest (BitcoinTestFramework):
         conn.request('POST', '/', '{"method": "getbestblockhash"}', headers)
         out1 = conn.getresponse().read()
         assert b'"error":null' in out1
-        assert conn.sock!=None  #connection must be closed because dashd should use keep-alive by default
+        assert conn.sock is not None  #connection must be closed because dashd should use keep-alive by default
 
         # Check excessive request size
         conn = http.client.HTTPConnection(urlNode2.hostname, urlNode2.port)

test/functional/mining_prioritisetransaction.py

@@ -78,7 +78,7 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
                 high_fee_tx = x
 
         # Something high-fee should have been mined!
-        assert high_fee_tx != None
+        assert high_fee_tx is not None
 
         # Add a prioritisation before a tx is in the mempool (de-prioritising a
         # high-fee transaction so that it's now low fee).

test/functional/test_framework/messages.py

@@ -709,7 +709,7 @@ class HeaderAndShortIDs:
         self.shortids = []
         self.prefilled_txn = []
 
-        if p2pheaders_and_shortids != None:
+        if p2pheaders_and_shortids is not None:
             self.header = p2pheaders_and_shortids.header
             self.nonce = p2pheaders_and_shortids.nonce
             self.shortids = p2pheaders_and_shortids.shortids
@@ -759,7 +759,7 @@ class BlockTransactionsRequest:
 
     def __init__(self, blockhash=0, indexes = None):
         self.blockhash = blockhash
-        self.indexes = indexes if indexes != None else []
+        self.indexes = indexes if indexes is not None else []
 
     def deserialize(self, f):
         self.blockhash = deser_uint256(f)
@@ -800,7 +800,7 @@ class BlockTransactions:
 
     def __init__(self, blockhash=0, transactions = None):
         self.blockhash = blockhash
-        self.transactions = transactions if transactions != None else []
+        self.transactions = transactions if transactions is not None else []
 
     def deserialize(self, f):
         self.blockhash = deser_uint256(f)
@@ -1299,7 +1299,7 @@ class msg_getdata:
     command = b"getdata"
 
     def __init__(self, inv=None):
-        self.inv = inv if inv != None else []
+        self.inv = inv if inv is not None else []
 
     def deserialize(self, f):
         self.inv = deser_vector(f, CInv)

test/functional/test_framework/test_node.py

@@ -79,7 +79,7 @@ class TestNode():
         self.binary = bitcoind
         self.coverage_dir = coverage_dir
         self.mocktime = mocktime
-        if extra_conf != None:
+        if extra_conf is not None:
             append_config(datadir, extra_conf)
         # Most callers will just need to add extra args to the standard list below.
         # For those callers that need more flexibity, they can just set the args property directly.

test/lint/lint-python.sh

@@ -35,7 +35,7 @@ enabled=(
     E701 # multiple statements on one line (colon)
     E702 # multiple statements on one line (semicolon)
     E703 # statement ends with a semicolon
-    # E711 # comparison to None should be 'if cond is None:'
+    E711 # comparison to None should be 'if cond is None:'
     E714 # test for object identity should be "is not"
     E721 # do not compare types, use "isinstance()"
     E742 # do not define classes named "l", "O", or "I"