Binary relations with element support

Change-Id: I2db566bf8f491119f2d431cef504c7a9a29f85ed
diff --git a/t/index/mate_dependency.t b/t/index/mate_dependency.t
index 9ec7f92..fab2bb5 100644
--- a/t/index/mate_dependency.t
+++ b/t/index/mate_dependency.t
@@ -15,11 +15,14 @@
 my $data = $tokens->to_data->{data}->{stream};
 
 # Unary relation
-is($data->[4]->[3], '<:mate/d:--$<b>32<i>4<s>1<s>1', '< rel 1');
-is($data->[4]->[4], '>:mate/d:--$<b>32<i>4<s>1<s>1', '> rel 1');
-is($data->[4]->[7], 'mate/d:NODE$<b>128<s>1', 'token for rel 1');
+is($data->[4]->[3], '<:mate/d:--$<b>32<i>4<s>1<s>1', '< rel 1 (unary)');
+is($data->[4]->[4], '>:mate/d:--$<b>32<i>4<s>1<s>1', '> rel 1 (unary)');
+is($data->[4]->[7], 'mate/d:NODE$<b>128<s>1', 'token for rel 1 (unary)');
 
-diag 'Test binary relations';
+is($data->[1]->[0], '>:mate/d:NK$<b>32<i>3<s>1<s>1', '> rel 2 (term-to-term)');
+is($data->[1]->[3], 'mate/d:NODE$<b>128<s>1', '< rel 2 (term-to-term)');
+is($data->[3]->[1], '<:mate/d:NK$<b>32<i>3<s>1<s>1', '< rel 2 (term-to-term)');
+is($data->[3]->[4], 'mate/d:NODE$<b>128<s>1', '< rel 2 (term-to-term)');
 
 done_testing;