X-Git-Url: http://git.shiar.net/perl/list-index.git/blobdiff_plain/3e2d0470d99683367de89a9ad4569247d3897355..e7b831494ed2dfb7333f0cf59f91cd7f14f9f9b6:/t/10-ranges.t

diff --git a/t/10-ranges.t b/t/10-ranges.t
index f935820..84f4dbb 100644
--- a/t/10-ranges.t
+++ b/t/10-ranges.t
@@ -32,6 +32,75 @@ subtest 'uniform alphanumeric' => sub {
 	is_deeply($index->ranges({pagesize => 300}), [qw(-c d-n o-)], 'large pagesize');
 };
 
+subtest 'context' => sub {
+	plan tests => 9;
+	my $index = List::Index->new([qw(
+		kkeg kl km kmlu knsy    koxb kpeo kuaa kuab kuac
+		kuapa kuq kur kux kzb   lc lg lgu lgua lguc
+		lguq lgur lgus lgx lka  lkq lks lln llq llx
+	)]) or return;
+	is_deeply(
+		$index->ranges({ pagesize=>10, context=>0, length=>5 }),
+		# ranges should match offsets exactly
+		[qw(-kuap. kuapa-lgup lguq-)],
+		'no context'
+	);
+	is_deeply(
+		$index->ranges({ pagesize=>10, context=>0 }),
+		# default length limits to 4 chars
+		[qw(-kuao kuap-lgup lguq-)],
+		'default length'
+	);
+	is_deeply(
+		$index->ranges({ pagesize=>10, context=>1 }),
+		# lookbehinds aren't shorter (kuac<kuap, lguc<lguq)
+		# 'kuap' can advance to 'kuq'
+		[qw(-kup kuq-lgup lguq-)],
+		'lookahead'
+	);
+TODO: {
+	local $TODO = 'backtrack';
+	is_deeply(
+		$index->ranges({ pagesize=>10, context=>2 }),
+		# allowed to advance to 'kur', but provides no benefits over 'kuq'
+		[qw(-kup kuq-lgup lguq-)],
+		'minimal lookahead'
+	);
+}
+	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 $index = List::Index->new([qw(
@@ -53,27 +122,3 @@ subtest 'context' => sub {
 	#pp($index->ranges({pagesize => 2, context => 2, length => 1}));
 };
 
-subtest 'distribution' => sub {
-	plan tests => 2;
-	my $index = List::Index->new([qw(
-		kkeg kl km kmlu knsy    koxb kpeo kuaa kuab kuac
-		kuap kuaq kuq kux kzb   lc lg lgu lgua lguc
-		lguq lgur lgus lgx lka  lkq lks lln llq llx
-	)]) or return;
-TODO: {
-	local $TODO = 'under development';
-	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'
-	);
-}
-