Use correct method to fetch IDs

lib/Parser/XML/Primitives/Construct.php

@@ -120,7 +120,7 @@ trait Construct {
 
     /** Primitive to fetch an Atom feed/entry identifier */
     protected function getIdAtom(): ?string {
-        return $this->fetchString("atom:id");
+        return $this->fetchString("atom:id", ".+");
     }
 
     /** Primitive to fetch an RSS feed/entry identifier
@@ -128,12 +128,12 @@ trait Construct {
      * Using RSS' <guid> for feed identifiers is non-standard, but harmless
      */
     protected function getIdRss2(): ?string {
-        return $this->fetchString("guid");
+        return $this->fetchString("guid", ".+");
     }
 
     /** Primitive to fetch a Dublin Core feed/entry identifier */
     protected function getIdDC(): ?string {
-        return $this->fetchString("dc:identifier");
+        return $this->fetchString("dc:identifier", ".+");
     }
 
     /** Primitive to fetch a collection of authors associated with a feed/entry via Dublin Core */

tests/cases/XML/feed-atom.yaml

@@ -26,3 +26,16 @@ Atom ID with whitespace:
         format: atom
         version: '1.0'
         id: 'http://example.com/'
+
+
+
+Bogus ID before good:
+    input: >
+        <feed xmlns="http://www.w3.org/2005/Atom">
+            <id/>
+            <id>http://example.com/</id>
+        </feed>
+    output:
+        format: atom
+        version: '1.0'
+        id: 'http://example.com/'

tests/cases/XML/feed-rss1.yaml

@@ -39,6 +39,19 @@ DC ID:
         version: '1.0'
         id: 'http://example.com/'
 
+Bogus DC ID before good:
+    input: >
+        <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/">
+            <channel>
+                <dc:identifier/>
+                <dc:identifier>http://example.com/</dc:identifier>
+            </channel>
+        </rdf:RDF>
+    output:
+        format: rdf
+        version: '1.0'
+        id: 'http://example.com/'
+
 DC ID with whitespace:
     input: >
         <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/" xmlns:dc="http://purl.org/dc/elements/1.1/">

tests/cases/XML/feed-rss2.yaml

@@ -38,6 +38,18 @@ Root GUID: # Any elements on the RSS2 root element should be ignored
     output:
         format: rss
 
+Bogus GUID before good:
+    input: >
+        <rss>
+            <channel>
+                <guid/>
+                <guid>http://example.com/</guid>
+            </channel>
+        </rss>
+    output:
+        format: rss
+        id: 'http://example.com/'
+
 Schedule interval 1:
     input: >
         <rss><channel>