Add test for invalid branch cache (fixed by 27ebe4efe98e)

tests/test-newbranch

@@ -1,26 +1,28 b''
 #!/bin/sh
 
 hg init t
 cd t
 
 echo foo > a
 hg add a
 hg ci -m "initial" -d "0 0"
 echo foo > .hg/branch
 hg ci -m "add branch name" -d "0 0"
 echo bar > .hg/branch
 hg ci -m "change branch name" -d "0 0"
 rm .hg/branch
 hg ci -m "clear branch name" -d "0 0"
 
 hg co foo
 cat .hg/branch
 echo bleah > a
 hg ci -m "modify a branch" -d "0 0"
 
 hg merge
 cat .hg/branch
 HG_MERGE=true hg ci -m "merge" -d "0 0"
 hg log
 
-
+echo % test for invalid branch cache
+hg rollback
+hg tip

tests/test-newbranch.out

@@ -1,43 +1,53 b''
 0 files updated, 0 files merged, 0 files removed, 0 files unresolved
 foo
 0 files updated, 0 files merged, 0 files removed, 0 files unresolved
 (branch merge, don't forget to commit)
 foo
 changeset:   5:dc140083783b
 branch:      foo
 tag:         tip
 parent:      4:98d14f698afe
 parent:      3:9d567d0b51f9
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     merge
 
 changeset:   4:98d14f698afe
 branch:      foo
 parent:      1:0079f24813e2
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     modify a branch
 
 changeset:   3:9d567d0b51f9
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     clear branch name
 
 changeset:   2:ed2bbf4e0102
 branch:      bar
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     change branch name
 
 changeset:   1:0079f24813e2
 branch:      foo
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     add branch name
 
 changeset:   0:db01e8ea3388
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     initial
 
+% test for invalid branch cache
+rolling back last transaction
+changeset:   4:98d14f698afe
+branch:      foo
+tag:         tip
+parent:      1:0079f24813e2
+user:        test
+date:        Thu Jan 01 00:00:00 1970 +0000
+summary:     modify a branch
+