Verify files at different levels in test

Author: jdkoren

test/dartdoc_test.dart

@@ -413,10 +413,16 @@ void main() {
           ['--rel-canonical-prefix', prefix], testPackageMinimumDir, tempDir);
       await dartdoc.generateDocsBase();
 
-      File file = File(path.join(tempDir.path, 'small', 'small-library.html'));
-      expect(file.existsSync(), isTrue);
+      // Verify files at different levels have correct <link> content.
+      File atRoot = File(path.join(tempDir.path, 'index.html'));
+      expect(atRoot.existsSync(), isTrue);
+      expect(atRoot.readAsStringSync(),
+          contains('<link rel="canonical" href="$prefix/index.html">'));
+      File notAtRoot =
+          File(path.join(tempDir.path, 'small', 'small-library.html'));
+      expect(notAtRoot.existsSync(), isTrue);
       expect(
-          file.readAsStringSync(),
+          notAtRoot.readAsStringSync(),
           contains(
               '<link rel="canonical" href="$prefix/small/small-library.html">'));
     });