+ is_deeply(
+ $index->ranges({ pagesize=>10, context=>3 }),
+ # shorten 'kuap' to 'ku' because lookbehind is 'kp...'
+ # 'lguq' matches 'lg', but may only backtrack to 'lgu'
+ [qw(-kt ku-lgt lgu-)],
+ 'lookbehind'
+ );
+ is_deeply(
+ $index->ranges({ pagesize=>10, context=>4 }),
+ [qw(-kt ku-lf lg-)],
+ 'maximal lookahead'
+ );
+ is_deeply(
+ $index->ranges({ pagesize=>10, context=>5 }),
+ # after forwarding 'kuap' to 'lc'
+ # disallow backtracking of 'lguq' to 'lc' to prevent qw[-k l-]
+ # so only lookahead (to 'lkq') remains
+ [qw(-k l-lj lk-)],
+ 'no lookbehind after full lookahead'
+ );
+ is_deeply(
+ $index->ranges({ pagesize=>10, context=>9 }),
+ # allow a single (10-9) entry (l-lf = lc) to remain
+ [qw(-k l-lf lg-)],
+ 'lookbehind after full lookahead'
+ );
+ is_deeply(
+ $index->ranges({ pagesize=>10, context=>10 }),
+ # allow the last page to go back upto 'lc', replacing the 2nd page
+ [qw(-k l-)],
+ 'full overlap'
+ );
+};
+
+subtest 'context' => sub {
+ plan tests => 4;
+ my $index = List::Index->new([qw(
+ baa1 baa2 baa3 baaa bbc cbc daaa ea eaaa zed
+ )]) or return;
+ is_deeply($index->ranges({pagesize => 2, context => 0}), [
+ qw(-baa. baa.-bbb bbc-daa. daaa-eaa. eaaa-)
+ ], 'no context');
+ is_deeply($index->ranges({pagesize => 2}), [
+ qw(-a b c d e-)
+ ], 'default context'); # context should be 1
+ is_deeply($index->ranges({pagesize => 2, context => 2}), [
+ qw(-a b-c d e-)
+ ], 'overlap'); # first item equals second due to large context
+ is_deeply($index->ranges({pagesize => 2, context => 0, length => 1}), [
+ qw(-a b-c d e-)
+ ], 'single char');
+
+ #pp($index->ranges({pagesize => 2, context => 2, length => 1}));
+};
+