diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -252,7 +252,10 @@ class histeditstate(object):
         for replacement in self.replacements:
             fp.write('%s%s\n' % (node.hex(replacement[0]), ''.join(node.hex(r)
                 for r in replacement[1])))
-        fp.write('%s\n' % self.backupfile)
+        backupfile = self.backupfile
+        if not backupfile:
+            backupfile = ''
+        fp.write('%s\n' % backupfile)
         fp.close()
 
     def _load(self):
@@ -890,21 +893,22 @@ def _histedit(ui, repo, state, *freeargs
 
 def bootstrapcontinue(ui, state, opts):
     repo = state.repo
-    action, currentnode = state.rules.pop(0)
-
-    actobj = actiontable[action].fromrule(state, currentnode)
+    if state.rules:
+        action, currentnode = state.rules.pop(0)
 
-    s = repo.status()
-    if s.modified or s.added or s.removed or s.deleted:
-        actobj.continuedirty()
+        actobj = actiontable[action].fromrule(state, currentnode)
+
         s = repo.status()
         if s.modified or s.added or s.removed or s.deleted:
-            raise util.Abort(_("working copy still dirty"))
+            actobj.continuedirty()
+            s = repo.status()
+            if s.modified or s.added or s.removed or s.deleted:
+                raise util.Abort(_("working copy still dirty"))
 
-    parentctx, replacements = actobj.continueclean()
+        parentctx, replacements = actobj.continueclean()
 
-    state.parentctxnode = parentctx.node()
-    state.replacements.extend(replacements)
+        state.parentctxnode = parentctx.node()
+        state.replacements.extend(replacements)
 
     return state
 
diff --git a/tests/test-run-tests.t b/tests/test-run-tests.t
--- a/tests/test-run-tests.t
+++ b/tests/test-run-tests.t
@@ -1,5 +1,12 @@
 This file tests the behavior of run-tests.py itself.
 
+Avoid interference from actual test env:
+
+  $ unset HGTEST_JOBS
+  $ unset HGTEST_TIMEOUT
+  $ unset HGTEST_PORT
+  $ unset HGTEST_SHELL
+
 Smoke test
 ============