diff --git a/tests/dummyssh b/tests/dummyssh
--- a/tests/dummyssh
+++ b/tests/dummyssh
@@ -13,9 +13,9 @@
 os.environ["SSH_CLIENT"] = "%s 1 2" % os.environ.get('LOCALIP', '127.0.0.1')
 
 log = open("dummylog", "ab")
-log.write("Got arguments")
+log.write(b"Got arguments")
 for i, arg in enumerate(sys.argv[1:]):
-    log.write(" %d:%s" % (i + 1, arg))
+    log.write(b" %d:%s" % (i + 1, arg))
 log.write("\n")
 log.close()
 hgcmd = sys.argv[2]
diff --git a/tests/flagprocessorext.py b/tests/flagprocessorext.py
--- a/tests/flagprocessorext.py
+++ b/tests/flagprocessorext.py
@@ -58,7 +58,7 @@
 def noopaddrevision(orig, self, text, transaction, link, p1, p2,
                     cachedelta=None, node=None,
                     flags=revlog.REVIDX_DEFAULT_FLAGS):
-    if '[NOOP]' in text:
+    if b'[NOOP]' in text:
         flags |= REVIDX_NOOP
     return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                 node=node, flags=flags)
@@ -66,7 +66,7 @@
 def b64addrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
-    if '[BASE64]' in text:
+    if b'[BASE64]' in text:
         flags |= REVIDX_BASE64
     return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                 node=node, flags=flags)
@@ -74,7 +74,7 @@
 def gzipaddrevision(orig, self, text, transaction, link, p1, p2,
                     cachedelta=None, node=None,
                     flags=revlog.REVIDX_DEFAULT_FLAGS):
-    if '[GZIP]' in text:
+    if b'[GZIP]' in text:
         flags |= REVIDX_GZIP
     return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                 node=node, flags=flags)
@@ -84,7 +84,7 @@
                     flags=revlog.REVIDX_DEFAULT_FLAGS):
     # This addrevision wrapper is meant to add a flag we will not have
     # transforms registered for, ensuring we handle this error case.
-    if '[FAIL]' in text:
+    if b'[FAIL]' in text:
         flags |= REVIDX_FAIL
     return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                 node=node, flags=flags)
diff --git a/tests/revlog-formatv0.py b/tests/revlog-formatv0.py
--- a/tests/revlog-formatv0.py
+++ b/tests/revlog-formatv0.py
@@ -22,27 +22,27 @@
 import sys
 
 files = [
-    ('formatv0/.hg/00changelog.i',
-     '000000000000004400000000000000000000000000000000000000'
-     '000000000000000000000000000000000000000000000000000000'
-     '0000a1ef0b125355d27765928be600cfe85784284ab3'),
-    ('formatv0/.hg/00changelog.d',
-     '756163613935613961356635353036303562366138343738336237'
-     '61623536363738616436356635380a757365720a3020300a656d70'
-     '74790a0a656d7074792066696c65'),
-    ('formatv0/.hg/00manifest.i',
-     '000000000000003000000000000000000000000000000000000000'
-     '000000000000000000000000000000000000000000000000000000'
-     '0000aca95a9a5f550605b6a84783b7ab56678ad65f58'),
-    ('formatv0/.hg/00manifest.d',
-     '75656d707479006238306465356431333837353835343163356630'
-     '35323635616431343461623966613836643164620a'),
-    ('formatv0/.hg/data/empty.i',
-     '000000000000000000000000000000000000000000000000000000'
-     '000000000000000000000000000000000000000000000000000000'
-     '0000b80de5d138758541c5f05265ad144ab9fa86d1db'),
-    ('formatv0/.hg/data/empty.d',
-     ''),
+    (b'formatv0/.hg/00changelog.i',
+     b'000000000000004400000000000000000000000000000000000000'
+     b'000000000000000000000000000000000000000000000000000000'
+     b'0000a1ef0b125355d27765928be600cfe85784284ab3'),
+    (b'formatv0/.hg/00changelog.d',
+     b'756163613935613961356635353036303562366138343738336237'
+     b'61623536363738616436356635380a757365720a3020300a656d70'
+     b'74790a0a656d7074792066696c65'),
+    (b'formatv0/.hg/00manifest.i',
+     b'000000000000003000000000000000000000000000000000000000'
+     b'000000000000000000000000000000000000000000000000000000'
+     b'0000aca95a9a5f550605b6a84783b7ab56678ad65f58'),
+    (b'formatv0/.hg/00manifest.d',
+     b'75656d707479006238306465356431333837353835343163356630'
+     b'35323635616431343461623966613836643164620a'),
+    (b'formatv0/.hg/data/empty.i',
+     b'000000000000000000000000000000000000000000000000000000'
+     b'000000000000000000000000000000000000000000000000000000'
+     b'0000b80de5d138758541c5f05265ad144ab9fa86d1db'),
+    (b'formatv0/.hg/data/empty.d',
+     b''),
 ]
 
 def makedirs(name):
diff --git a/tests/test-bundle2-multiple-changegroups.t b/tests/test-bundle2-multiple-changegroups.t
--- a/tests/test-bundle2-multiple-changegroups.t
+++ b/tests/test-bundle2-multiple-changegroups.t
@@ -13,24 +13,24 @@
   >     # in 'heads' as intermediate heads for the first changegroup.
   >     intermediates = [repo[r].p1().node() for r in heads]
   >     outgoing = discovery.outgoing(repo, common, intermediates)
-  >     cg = changegroup.makechangegroup(repo, outgoing, '01',
+  >     cg = changegroup.makechangegroup(repo, outgoing, b'01',
   >                                      source, bundlecaps=bundlecaps)
-  >     bundler.newpart('output', data='changegroup1')
-  >     bundler.newpart('changegroup', data=cg.getchunks())
+  >     bundler.newpart(b'output', data=b'changegroup1')
+  >     bundler.newpart(b'changegroup', data=cg.getchunks())
   >     outgoing = discovery.outgoing(repo, common + intermediates, heads)
-  >     cg = changegroup.makechangegroup(repo, outgoing, '01',
+  >     cg = changegroup.makechangegroup(repo, outgoing, b'01',
   >                                      source, bundlecaps=bundlecaps)
-  >     bundler.newpart('output', data='changegroup2')
-  >     bundler.newpart('changegroup', data=cg.getchunks())
+  >     bundler.newpart(b'output', data=b'changegroup2')
+  >     bundler.newpart(b'changegroup', data=cg.getchunks())
   > 
   > def _pull(repo, *args, **kwargs):
   >   pullop = _orig_pull(repo, *args, **kwargs)
-  >   repo.ui.write('pullop.cgresult is %d\n' % pullop.cgresult)
+  >   repo.ui.write(b'pullop.cgresult is %d\n' % pullop.cgresult)
   >   return pullop
   > 
   > _orig_pull = exchange.pull
   > exchange.pull = _pull
-  > exchange.getbundle2partsmapping['changegroup'] = _getbundlechangegrouppart
+  > exchange.getbundle2partsmapping[b'changegroup'] = _getbundlechangegrouppart
   > EOF
 
   $ cat >> $HGRCPATH << EOF
diff --git a/tests/test-diffstat.t b/tests/test-diffstat.t
--- a/tests/test-diffstat.t
+++ b/tests/test-diffstat.t
@@ -35,7 +35,7 @@
 
   $ hg ci -m appenda
 
-  >>> open("c", "wb").write("\0")
+  >>> open("c", "wb").write(b"\0")
   $ touch d
   $ hg add c d
 
@@ -54,7 +54,7 @@
 
   $ hg ci -m createb
 
-  >>> open("file with spaces", "wb").write("\0")
+  >>> open("file with spaces", "wb").write(b"\0")
   $ hg add "file with spaces"
 
 Filename with spaces diffstat: