Posts: Add test coverage for get_preview_post_link().

Props swissspidy.
Fixes #35915.


git-svn-id: https://develop.svn.wordpress.org/trunk@37566 602fd350-edb4-49c9-b593-d223f7449a82

Author: DrewAPicture

tests/phpunit/tests/link/getPreviewPostLink.php

@@ -0,0 +1,66 @@
+<?php
+/**
+ * @group link
+ * @covers ::get_preview_post_link
+ */
+class Tests_Link_GetPreviewPostLink extends WP_UnitTestCase {
+
+	public function test_get_preview_post_link() {
+		$post = self::factory()->post->create();
+
+		$this->assertEquals( add_query_arg( 'preview', 'true', get_permalink( $post ) ), get_preview_post_link( $post) );
+	}
+
+	public function test_get_preview_post_link_should_add_additional_query_vars() {
+		$post = self::factory()->post->create();
+
+		$expected = add_query_arg( array(
+			'foo'     => 'bar',
+			'bar'     => 'baz',
+			'preview' => 'true',
+		), get_permalink( $post ) );
+
+		$this->assertEquals( $expected, get_preview_post_link( $post, array(
+			'foo' => 'bar',
+			'bar' => 'baz',
+		) ) );
+	}
+
+	public function test_get_preview_post_link_should_use_custom_base_preview_link() {
+		$post = self::factory()->post->create();
+
+		$expected = 'https://google.com/?foo=bar&bar=baz&preview=true';
+
+		$this->assertEquals( $expected, get_preview_post_link( $post, array(
+			'foo' => 'bar',
+			'bar' => 'baz',
+		), 'https://google.com/' ) );
+	}
+
+	public function test_get_preview_post_link_should_return_null_for_non_existent_post() {
+		$this->assertNull( get_preview_post_link() );
+		$this->assertNull( get_preview_post_link( 9999 ) );
+		$this->assertNull( get_preview_post_link( 'foo' ) );
+	}
+
+	public function test_get_preview_post_link_for_global_post() {
+		$post = self::factory()->post->create_and_get();
+
+		$GLOBALS['post'] = $post;
+
+		$this->assertEquals( add_query_arg( 'preview', 'true', get_permalink( $post ) ), get_preview_post_link() );
+	}
+
+	public function test_get_preview_post_link_should_return_empty_string_for_non_viewable_post_type() {
+		$post_type = register_post_type( rand_str(12), array(
+			'public' => false,
+		) );
+
+		$post = self::factory()->post->create( array(
+			'post_type' => $post_type->name
+		) );
+
+		$this->assertSame( '', get_preview_post_link( $post ) );
+	}
+
+}