Add regression tests for the child combinator matching the root

tests/Issues/Issue74Test.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace QueryPathTests;
+
+/**
+ * The right-hand side of `X > *` also matches the document element, whose parent is the
+ * document rather than an element.
+ */
+class Issue74Test extends TestCase
+{
+	protected const XML = '<?xml version="1.0"?><root><wrap><a/><b/></wrap></root>';
+
+	protected const HTML = '<html><body><ul><li>a</li><li>b</li></ul></body></html>';
+
+	/**
+	 * Get the tag name of every element in the match set.
+	 *
+	 * @param \QueryPath\DOMQuery $query
+	 *
+	 * @return array
+	 */
+	protected function tagNames($query): array
+	{
+		$names = [];
+		foreach ($query->get() as $node) {
+			$names[] = $node->tagName;
+		}
+
+		return $names;
+	}
+
+	public function testChildCombinatorWithUniversalSelectorInXml(): void
+	{
+		$this->assertSame(['a', 'b'], $this->tagNames(qp(self::XML, 'wrap > *')));
+		$this->assertSame(['a', 'b'], $this->tagNames(qp(self::XML)->find('wrap > *')));
+		$this->assertSame(['wrap'], $this->tagNames(qp(self::XML, 'root > *')));
+		$this->assertSame(['wrap', 'a', 'b'], $this->tagNames(qp(self::XML, '* > *')));
+	}
+
+	/**
+	 * The other combinators also start from a right-hand side that matches the root element.
+	 */
+	public function testOtherCombinatorsWithUniversalSelectorInXml(): void
+	{
+		$this->assertSame(['wrap', 'a', 'b'], $this->tagNames(qp(self::XML, '* *')));
+		$this->assertSame(['b'], $this->tagNames(qp(self::XML, '* + *')));
+		$this->assertSame(['b'], $this->tagNames(qp(self::XML, '* ~ *')));
+	}
+
+	public function testChildCombinatorWithUniversalSelectorInHtml(): void
+	{
+		foreach (['htmlqp', 'html5qp'] as $factory) {
+			$this->assertSame(['li', 'li'], $this->tagNames($factory(self::HTML, 'ul > *')), $factory);
+			$this->assertSame(['li', 'li'], $this->tagNames($factory(self::HTML)->find('ul > *')), $factory);
+		}
+	}
+}