Fix test_amp_remove_paired_endpoint in WP 5.9 by removing empty query string (#6727)

Author: westonruter

src/PairedUrl.php

@@ -24,7 +24,9 @@ final class PairedUrl implements Service {
 	 * @return string URL.
 	 */
 	public function remove_query_var( $url ) {
-		return remove_query_arg( amp_get_slug(), $url );
+		$url = remove_query_arg( amp_get_slug(), $url );
+		$url = str_replace( '?#', '#', $url ); // See <https://core.trac.wordpress.org/ticket/44499>.
+		return $url;
 	}
 
 	/**

tests/php/test-amp-helper-functions.php

@@ -651,7 +651,7 @@ public function test_amp_remove_paired_endpoint() {
 		$this->assertEquals( 'https://example.com/foo/', amp_remove_paired_endpoint( 'https://example.com/foo/?amp' ) );
 		$this->assertEquals( 'https://example.com/foo/', amp_remove_paired_endpoint( 'https://example.com/foo/?amp=1' ) );
 		$this->assertEquals( 'https://example.com/foo/', amp_remove_paired_endpoint( 'https://example.com/foo/amp/?amp=1' ) );
-		$this->assertEquals( 'https://example.com/foo/?#bar', amp_remove_paired_endpoint( 'https://example.com/foo/?amp#bar' ) );
+		$this->assertEquals( 'https://example.com/foo/#bar', amp_remove_paired_endpoint( 'https://example.com/foo/?amp#bar' ) );
 		$this->assertEquals( 'https://example.com/foo/', amp_remove_paired_endpoint( 'https://example.com/foo/amp/' ) );
 		$this->assertEquals( 'https://example.com/foo/?blaz', amp_remove_paired_endpoint( 'https://example.com/foo/amp/?blaz' ) );
 	}