test-grep: add tests for --follow with/without --diff and/or paths
This tests the behavior of cmdutil.walkchangerevs().
I'm going to rewrite cmdutil.walkchangerevs() to leverage the "log -f"
logic, but the code coverage looked quite small. And the history traversal
of "grep -f" goes wrong in various ways.
$ hg init a
$ cd a
$ hg diff inexistent1 inexistent2
inexistent1: * (glob)
inexistent2: * (glob)
$ echo bar > foo
$ hg add foo
$ hg ci -m 'add foo'
$ echo foobar > foo
$ hg ci -m 'change foo'
$ hg --quiet diff -r 0 -r 1
diff -r a99fb63adac3 -r 9b8568d3af2f foo
--- a/foo Thu Jan 01 00:00:00 1970 +0000
+++ b/foo Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-bar
+foobar
$ hg diff -r 0 -r 1
diff -r a99fb63adac3 -r 9b8568d3af2f foo
--- a/foo Thu Jan 01 00:00:00 1970 +0000
+++ b/foo Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-bar
+foobar
$ hg --verbose diff -r 0 -r 1
diff -r a99fb63adac3 -r 9b8568d3af2f foo
--- a/foo Thu Jan 01 00:00:00 1970 +0000
+++ b/foo Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-bar
+foobar
$ hg --debug diff -r 0 -r 1
diff -r a99fb63adac3f31816a22f665bc3b7a7655b30f4 -r 9b8568d3af2f1749445eef03aede868a6f39f210 foo
--- a/foo Thu Jan 01 00:00:00 1970 +0000
+++ b/foo Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +1,1 @@
-bar
+foobar
$ cd ..