Index: tests/phpunit/tests/comment.php
===================================================================
--- tests/phpunit/tests/comment.php	(revision 32501)
+++ tests/phpunit/tests/comment.php	(working copy)
@@ -148,4 +148,93 @@
 			unset( $_SERVER['REMOTE_ADDR'] );
 		}
 	}
+
+	public function test_check_comment() {
+		$author       = 'BobtheBuilder';
+		$author_email = 'bob@example.com';
+		$author_url   = 'http://example.com';
+		$comment      = 'Can we fix it? Yes, we can (thanks to Wendy).';
+		$author_ip    = '192.168.0.1';
+		$user_agent   = '';
+		$comment_type = '';
+
+		update_option( 'comment_whitelist', 0 );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertTrue( $results );
+
+		update_option( 'comment_whitelist', 1 );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertFalse( $results );
+	}
+
+	public function test_check_comment_previously_approved() {
+		$post_id = $this->factory->post->create();
+		$prev_args = array(
+			'comment_post_ID'      => $post_id,
+			'comment_content'      => 'Can we build it?',
+			'comment_approved'     => 0,
+			'comment_author_email' => 'bob@example.com',
+			'comment_author'       => 'BobtheBuilder',
+		);
+		$prev_comment_id = $this->factory->comment->create( $prev_args );
+
+		$author       = 'BobtheBuilder';
+		$author_email = 'bob@example.com';
+		$author_url   = 'http://example.com';
+		$comment      = 'Can we fix it? Yes, we can (thanks to Wendy).';
+		$author_ip    = '192.168.0.1';
+		$user_agent   = '';
+		$comment_type = '';
+
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertFalse( $results );
+
+		// Approve the previous comment.
+		wp_update_comment( array(
+			'comment_ID'       => $prev_comment_id,
+			'comment_approved' => 1,
+		) );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertTrue( $results );
+	}
+
+	public function test_check_comment_moderation_keys() {
+		$author       = 'WendytheBuilder';
+		$author_email = 'wendy@example.com';
+		$author_url   = 'http://example.com';
+		$comment      = 'Has anyone seen Scoop?';
+		$author_ip    = '192.168.0.1';
+		$user_agent   = '';
+		$comment_type = '';
+
+		update_option( 'comment_whitelist', 0 );
+
+		update_option( 'moderation_keys',"poop\nhiney\nscoop" );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertFalse( $results );
+
+		update_option( 'moderation_keys',"poop\nhiney\n" );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertTrue( $results );
+	}
+
+	public function test_check_comment_max_links() {
+		$author       = 'BobtheBuilder';
+		$author_email = 'bob@example.com';
+		$author_url   = 'http://example.com';
+		$comment      = 'This is a comment with <a href="http://example.com">multiple</a> <a href="http://bob.example.com">links</a>.';
+		$author_ip    = '192.168.0.1';
+		$user_agent   = '';
+		$comment_type = '';
+
+		update_option( 'comment_whitelist', 0 );
+
+		update_option( 'comment_max_links', 2 );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertFalse( $results );
+
+		update_option( 'comment_max_links', 3 );
+		$results = check_comment( $author, $author_email, $author_url, $comment, $author_ip, $user_agent, $comment_type );
+		$this->assertTrue( $results );
+	}
 }