diff --git a/tests/test-ssh-proto-unbundle.t b/tests/test-ssh-proto-unbundle.t
--- a/tests/test-ssh-proto-unbundle.t
+++ b/tests/test-ssh-proto-unbundle.t
@@ -161,10 +161,12 @@ Test pushing to a server that has a pret
   > import sys
   > def hook1line(ui, repo, **kwargs):
   >     ui.write(b'ui.write 1 line\n')
+  >     ui.flush()
   >     return 1
   > def hook2lines(ui, repo, **kwargs):
   >     ui.write(b'ui.write 2 lines 1\n')
   >     ui.write(b'ui.write 2 lines 2\n')
+  >     ui.flush()
   >     return 1
   > def hook1lineflush(ui, repo, **kwargs):
   >     ui.write(b'ui.write 1 line flush\n')
@@ -181,21 +183,31 @@ Test pushing to a server that has a pret
   >     ui.write_err(b'ui.write_err 1\n')
   >     ui.write(b'ui.write 2\n')
   >     ui.write_err(b'ui.write_err 2\n')
+  >     ui.flush()
   >     return 1
   > def hookprintstdout(ui, repo, **kwargs):
   >     print('printed line')
+  >     sys.stdout.flush()
   >     return 1
   > def hookprintandwrite(ui, repo, **kwargs):
   >     print('print 1')
+  >     sys.stdout.flush()
   >     ui.write(b'ui.write 1\n')
+  >     ui.flush()
   >     print('print 2')
+  >     sys.stdout.flush()
   >     ui.write(b'ui.write 2\n')
+  >     ui.flush()
   >     return 1
   > def hookprintstderrandstdout(ui, repo, **kwargs):
   >     print('stdout 1')
+  >     sys.stdout.flush()
   >     print('stderr 1', file=sys.stderr)
+  >     sys.stderr.flush()
   >     print('stdout 2')
+  >     sys.stdout.flush()
   >     print('stderr 2', file=sys.stderr)
+  >     sys.stderr.flush()
   >     return 1
   > EOF
 
@@ -1046,10 +1058,10 @@ Mixed print() and ui.write() are both ca
   e>     adding manifests\n
   e>     adding file changes\n
   e>     added 1 changesets with 1 changes to 1 files\n
+  e>     print 1\n
   e>     ui.write 1\n
+  e>     print 2\n
   e>     ui.write 2\n
-  e>     print 1\n
-  e>     print 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.fail hook failed\n
@@ -1106,10 +1118,10 @@ Mixed print() and ui.write() are both ca
   e>     adding manifests\n
   e>     adding file changes\n
   e>     added 1 changesets with 1 changes to 1 files\n
+  e>     print 1\n
   e>     ui.write 1\n
+  e>     print 2\n
   e>     ui.write 2\n
-  e>     print 1\n
-  e>     print 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.fail hook failed\n
@@ -1180,10 +1192,10 @@ print() to stdout and stderr both get ca
   e>     adding manifests\n
   e>     adding file changes\n
   e>     added 1 changesets with 1 changes to 1 files\n
+  e>     stdout 1\n
   e>     stderr 1\n
+  e>     stdout 2\n
   e>     stderr 2\n
-  e>     stdout 1\n
-  e>     stdout 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.fail hook failed\n
@@ -1240,10 +1252,10 @@ print() to stdout and stderr both get ca
   e>     adding manifests\n
   e>     adding file changes\n
   e>     added 1 changesets with 1 changes to 1 files\n
+  e>     stdout 1\n
   e>     stderr 1\n
+  e>     stdout 2\n
   e>     stderr 2\n
-  e>     stdout 1\n
-  e>     stdout 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.fail hook failed\n
@@ -1731,10 +1743,10 @@ Shell and Python hooks writing to stdout
   e>     shell stderr 1\n
   e>     shell stdout 2\n
   e>     shell stderr 2\n
+  e>     stdout 1\n
   e>     stderr 1\n
+  e>     stdout 2\n
   e>     stderr 2\n
-  e>     stdout 1\n
-  e>     stdout 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.b hook failed\n
@@ -1795,10 +1807,10 @@ Shell and Python hooks writing to stdout
   e>     shell stderr 1\n
   e>     shell stdout 2\n
   e>     shell stderr 2\n
+  e>     stdout 1\n
   e>     stderr 1\n
+  e>     stdout 2\n
   e>     stderr 2\n
-  e>     stdout 1\n
-  e>     stdout 2\n
   e>     transaction abort!\n
   e>     rollback completed\n
   e>     abort: pretxnchangegroup.b hook failed\n
diff --git a/tests/test-ssh.t b/tests/test-ssh.t
--- a/tests/test-ssh.t
+++ b/tests/test-ssh.t
@@ -272,12 +272,14 @@ a bad, evil hook that prints to stdout
   $ cat <<EOF > $TESTTMP/badhook
   > import sys
   > sys.stdout.write("KABOOM\n")
+  > sys.stdout.flush()
   > EOF
 
   $ cat <<EOF > $TESTTMP/badpyhook.py
   > import sys
   > def hook(ui, repo, hooktype, **kwargs):
   >     sys.stdout.write("KABOOM IN PROCESS\n")
+  >     sys.stdout.flush()
   > EOF
 
   $ cat <<EOF >> ../remote/.hg/hgrc
@@ -456,6 +458,7 @@ stderr from remote commands should be pr
   > def wrappedpush(orig, repo, *args, **kwargs):
   >     res = orig(repo, *args, **kwargs)
   >     repo.ui.write('local stdout\n')
+  >     repo.ui.flush()
   >     return res
   > 
   > def extsetup(ui):