diff --git a/t/primary.t b/t/primary.t
new file mode 100644
index 0000000..831124e
--- /dev/null
+++ b/t/primary.t
@@ -0,0 +1,88 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use Test::More;
+use Mojo::ByteStream 'b';
+use utf8;
+use lib 'lib', '../lib';
+
+use_ok('KorAP::Document::Primary');
+
+my $t = "Der März ging vorüber und demnächst würde es Herbstblätter regnen.";
+
+ok(my $p = KorAP::Document::Primary->new($t), 'Constructor');
+
+is($p->data_length, 66, 'Text has correct length');
+
+is($p->data, $t, 'Text is identical');
+is($p->data(0,3), 'Der', 'Text is identical');
+is($p->data(4,8), 'März', 'Text is identical');
+is($p->data(26,35), 'demnächst', 'Text is identical');
+
+is($p->data_bytes(0,3), 'Der', 'Text is identical');
+is($p->data_bytes(4,9), 'März', 'Text is identical');
+is($p->data_bytes(28,38), 'demnächst', 'Text is identical');
+
+is($p->bytes2chars(4), 4, 'Byte offset matches');
+is($p->bytes2chars(9), 8, 'Byte offset matches');
+is($p->bytes2chars(28), 26, 'Byte offset matches');
+is($p->bytes2chars(38), 35, 'Byte offset matches');
+
+is(
+  $p->data(
+    $p->bytes2chars(17),
+    $p->bytes2chars(45)
+  ),
+  $p->data_bytes(17,45),
+  'Text is identical'
+);
+
+$t = 'Er dächte, daß dies „für alle Elemente gilt“.';
+
+ok($p = KorAP::Document::Primary->new($t), 'Constructor');
+
+is($p->data_length, 45, 'Text has correct length');
+
+is($p->data, $t, 'Text is identical');
+is($p->data(0,2), 'Er', 'Text is identical');
+is($p->data(3,9), 'dächte', 'Text is identical');
+is($p->data(21,24), 'für', 'Text is identical');
+is($p->data(20,21), '„', 'Text is identical');
+is($p->data(43,44), '“', 'Text is identical');
+is($p->data(44,45), '.', 'Text is identical');
+
+is($p->data_bytes(0,2), 'Er', 'Text is identical');
+is($p->bytes2chars(0),0, 'b2c correct');
+is($p->bytes2chars(2),2, 'b2c correct');
+is($p->data_bytes(3,10), 'dächte', 'Text is identical');
+is($p->bytes2chars(3),3, 'b2c correct');
+is($p->bytes2chars(10),9, 'b2c correct');
+is($p->data_bytes(25,29), 'für', 'Text is identical');
+is($p->bytes2chars(25),21, 'b2c correct');
+is($p->bytes2chars(29),24, 'b2c correct');
+is($p->data_bytes(22,25), '„', 'Text is identical');
+is($p->bytes2chars(22),20, 'b2c correct');
+is($p->bytes2chars(25),21, 'b2c correct');
+is($p->data_bytes(48,51), '“', 'Text is identical');
+is($p->bytes2chars(48),43, 'b2c correct');
+is($p->bytes2chars(51),44, 'b2c correct');
+is($p->data_bytes(51,52), '.', 'Text is identical');
+is($p->bytes2chars(52),45, 'b2c correct');
+
+is(
+  $p->data(
+    $p->bytes2chars(17),
+    $p->bytes2chars(45)
+  ),
+  $p->data_bytes(17,45),
+  'Text is identical'
+);
+
+
+#ok($p = KorAP::Document::Primary->new($t), 'Constructor');
+is($p->xip2chars(0), 0, 'Fine');
+is($p->xip2chars(7), 6, 'Fine');
+#diag $p->data($p->latinbytes2chars(3),$p->latinbytes2chars(9));
+
+
+done_testing;