diff --git a/core/tests/Drupal/Tests/Component/Gettext/PoHeaderTest.php b/core/tests/Drupal/Tests/Component/Gettext/PoHeaderTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..d3fb94047332f11c301cacb21f5bc9b0275cf9c2
--- /dev/null
+++ b/core/tests/Drupal/Tests/Component/Gettext/PoHeaderTest.php
@@ -0,0 +1,375 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Component\Gettext\PoHeaderTest.
+ */
+
+namespace Drupal\Tests\Component\Gettext;
+
+use Drupal\Component\Gettext\PoHeader;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * Unit tests for the Gettext PO file header handling features.
+ *
+ * @see Drupal\Component\Gettext\PoHeader.
+ *
+ * @group Gettext
+ */
+class PoHeaderTest extends UnitTestCase {
+
+ /**
+ * Tests that plural expressions are evaluated correctly.
+ *
+ * Validate that the given plural expressions is evaluated with the correct
+ * plural formula.
+ *
+ * @param string $plural
+ * The plural expression.
+ * @param array $expected
+ * Array of expected plural positions keyed by plural value.
+ *
+ * @dataProvider providerTestPluralsFormula
+ */
+ public function testPluralsFormula($plural, $expected) {
+ $p = new PoHeader();
+ $parsed = $p->parsePluralForms($plural);
+ list($nplurals, $new_plural) = $parsed;
+ foreach ($expected as $number => $plural_form) {
+ $result = isset($new_plural[$number]) ? $new_plural[$number] : $new_plural['default'];
+ $this->assertEquals($result, $plural_form, 'Difference found at ' . $number . ': ' . $plural_form . ' versus ' . $result);
+ }
+ }
+
+ /**
+ * Data provider for testPluralsFormula.
+ *
+ * Gets pairs of plural expressions and expected plural positions keyed by
+ * plural value.
+ *
+ * @return array
+ * Pairs of plural expressions and expected plural positions keyed by plural
+ * value.
+ */
+ public function providerTestPluralsFormula() {
+ return array(
+ array(
+ 'nplurals=1; plural=0;',
+ array('default' => 0),
+ ),
+ array(
+ 'nplurals=2; plural=(n > 1);',
+ array(0 => 0, 1 => 0, 'default' => 1),
+ ),
+ array(
+ 'nplurals=2; plural=(n!=1);',
+ array(1 => 0, 'default' => 1),
+ ),
+ array(
+ 'nplurals=2; plural=(((n==1)||((n%10)==1))?(0):1);',
+ array(
+ 1 => 0,
+ 11 => 0,
+ 21 => 0,
+ 31 => 0,
+ 41 => 0,
+ 51 => 0,
+ 61 => 0,
+ 71 => 0,
+ 81 => 0,
+ 91 => 0,
+ 101 => 0,
+ 111 => 0,
+ 121 => 0,
+ 131 => 0,
+ 141 => 0,
+ 151 => 0,
+ 161 => 0,
+ 171 => 0,
+ 181 => 0,
+ 191 => 0,
+ 'default' => 1,
+ ),
+ ),
+ array(
+ 'nplurals=3; plural=((((n%10)==1)&&((n%100)!=11))?(0):(((((n%10)>=2)&&((n%10)<=4))&&(((n%100)<10)||((n%100)>=20)))?(1):2));',
+ array(
+ 1 => 0,
+ 2 => 1,
+ 3 => 1,
+ 4 => 1,
+ 21 => 0,
+ 22 => 1,
+ 23 => 1,
+ 24 => 1,
+ 31 => 0,
+ 32 => 1,
+ 33 => 1,
+ 34 => 1,
+ 41 => 0,
+ 42 => 1,
+ 43 => 1,
+ 44 => 1,
+ 51 => 0,
+ 52 => 1,
+ 53 => 1,
+ 54 => 1,
+ 61 => 0,
+ 62 => 1,
+ 63 => 1,
+ 64 => 1,
+ 71 => 0,
+ 72 => 1,
+ 73 => 1,
+ 74 => 1,
+ 81 => 0,
+ 82 => 1,
+ 83 => 1,
+ 84 => 1,
+ 91 => 0,
+ 92 => 1,
+ 93 => 1,
+ 94 => 1,
+ 101 => 0,
+ 102 => 1,
+ 103 => 1,
+ 104 => 1,
+ 121 => 0,
+ 122 => 1,
+ 123 => 1,
+ 124 => 1,
+ 131 => 0,
+ 132 => 1,
+ 133 => 1,
+ 134 => 1,
+ 141 => 0,
+ 142 => 1,
+ 143 => 1,
+ 144 => 1,
+ 151 => 0,
+ 152 => 1,
+ 153 => 1,
+ 154 => 1,
+ 161 => 0,
+ 162 => 1,
+ 163 => 1,
+ 164 => 1,
+ 171 => 0,
+ 172 => 1,
+ 173 => 1,
+ 174 => 1,
+ 181 => 0,
+ 182 => 1,
+ 183 => 1,
+ 184 => 1,
+ 191 => 0,
+ 192 => 1,
+ 193 => 1,
+ 194 => 1,
+ 'default' => 2,
+ ),
+ ),
+ array(
+ 'nplurals=3; plural=((n==1)?(0):(((n>=2)&&(n<=4))?(1):2));',
+ array(
+ 1 => 0,
+ 2 => 1,
+ 3 => 1,
+ 4 => 1,
+ 'default' => 2,
+ ),
+ ),
+ array(
+ 'nplurals=3; plural=((n==1)?(0):(((n==0)||(((n%100)>0)&&((n%100)<20)))?(1):2));',
+ array(
+ 0 => 1,
+ 1 => 0,
+ 2 => 1,
+ 3 => 1,
+ 4 => 1,
+ 5 => 1,
+ 6 => 1,
+ 7 => 1,
+ 8 => 1,
+ 9 => 1,
+ 10 => 1,
+ 11 => 1,
+ 12 => 1,
+ 13 => 1,
+ 14 => 1,
+ 15 => 1,
+ 16 => 1,
+ 17 => 1,
+ 18 => 1,
+ 19 => 1,
+ 101 => 1,
+ 102 => 1,
+ 103 => 1,
+ 104 => 1,
+ 105 => 1,
+ 106 => 1,
+ 107 => 1,
+ 108 => 1,
+ 109 => 1,
+ 110 => 1,
+ 111 => 1,
+ 112 => 1,
+ 113 => 1,
+ 114 => 1,
+ 115 => 1,
+ 116 => 1,
+ 117 => 1,
+ 118 => 1,
+ 119 => 1,
+ 'default' => 2,
+ ),
+ ),
+ array(
+ 'nplurals=3; plural=((n==1)?(0):(((((n%10)>=2)&&((n%10)<=4))&&(((n%100)<10)||((n%100)>=20)))?(1):2));',
+ array(
+ 1 => 0,
+ 2 => 1,
+ 3 => 1,
+ 4 => 1,
+ 22 => 1,
+ 23 => 1,
+ 24 => 1,
+ 32 => 1,
+ 33 => 1,
+ 34 => 1,
+ 42 => 1,
+ 43 => 1,
+ 44 => 1,
+ 52 => 1,
+ 53 => 1,
+ 54 => 1,
+ 62 => 1,
+ 63 => 1,
+ 64 => 1,
+ 72 => 1,
+ 73 => 1,
+ 74 => 1,
+ 82 => 1,
+ 83 => 1,
+ 84 => 1,
+ 92 => 1,
+ 93 => 1,
+ 94 => 1,
+ 102 => 1,
+ 103 => 1,
+ 104 => 1,
+ 122 => 1,
+ 123 => 1,
+ 124 => 1,
+ 132 => 1,
+ 133 => 1,
+ 134 => 1,
+ 142 => 1,
+ 143 => 1,
+ 144 => 1,
+ 152 => 1,
+ 153 => 1,
+ 154 => 1,
+ 162 => 1,
+ 163 => 1,
+ 164 => 1,
+ 172 => 1,
+ 173 => 1,
+ 174 => 1,
+ 182 => 1,
+ 183 => 1,
+ 184 => 1,
+ 192 => 1,
+ 193 => 1,
+ 194 => 1,
+ 'default' => 2,
+ ),),
+ array(
+ 'nplurals=4; plural=(((n==1)||(n==11))?(0):(((n==2)||(n==12))?(1):(((n>2)&&(n<20))?(2):3)));',
+ array(
+ 1 => 0,
+ 2 => 1,
+ 3 => 2,
+ 4 => 2,
+ 5 => 2,
+ 6 => 2,
+ 7 => 2,
+ 8 => 2,
+ 9 => 2,
+ 10 => 2,
+ 11 => 0,
+ 12 => 1,
+ 13 => 2,
+ 14 => 2,
+ 15 => 2,
+ 16 => 2,
+ 17 => 2,
+ 18 => 2,
+ 19 => 2,
+ 'default' => 3,
+ ),
+ ),
+ array(
+ 'nplurals=4; plural=(((n%100)==1)?(0):(((n%100)==2)?(1):((((n%100)==3)||((n%100)==4))?(2):3)));',
+ array(
+ 1 => 0,
+ 2 => 1,
+ 3 => 2,
+ 4 => 2,
+ 101 => 0,
+ 102 => 1,
+ 103 => 2,
+ 104 => 2,
+ 'default' => 3,
+ ),
+ ),
+ array(
+ 'nplurals=5; plural=((n==1)?(0):((n==2)?(1):((n<7)?(2):((n<11)?(3):4))));',
+ array(
+ 0 => 2,
+ 1 => 0,
+ 2 => 1,
+ 3 => 2,
+ 4 => 2,
+ 5 => 2,
+ 6 => 2,
+ 7 => 3,
+ 8 => 3,
+ 9 => 3,
+ 10 => 3,
+ 'default' => 4,
+ ),
+ ),
+ array(
+ 'nplurals=6; plural=((n==1)?(0):((n==0)?(1):((n==2)?(2):((((n%100)>=3)&&((n%100)<=10))?(3):((((n%100)>=11)&&((n%100)<=99))?(4):5)))));',
+ array(
+ 0 => 1,
+ 1 => 0,
+ 2 => 2,
+ 3 => 3,
+ 4 => 3,
+ 5 => 3,
+ 6 => 3,
+ 7 => 3,
+ 8 => 3,
+ 9 => 3,
+ 10 => 3,
+ 100 => 5,
+ 101 => 5,
+ 102 => 5,
+ 103 => 3,
+ 104 => 3,
+ 105 => 3,
+ 106 => 3,
+ 107 => 3,
+ 108 => 3,
+ 109 => 3,
+ 110 => 3,
+ 'default' => 4,
+ ),
+ ),
+ );
+ }
+
+}