Fix running testsuite from out-of-tre

Fix running the test suite via `TestPackage("AutoDoc")` when the
current working directory is not the package root. This is
essential for passing the package distribution tests.

Co-authored-by: Codex <codex@openai.com>

Author: fingolfin

CHANGES.md

@@ -1,5 +1,9 @@
 This file describes changes in the AutoDoc package.
 
+## 2026.03.18
+  - Fix running the test suite via `TestPackage("AutoDoc")` when the
+    current working directory is not the package root
+
 ## 2026.03.17
 
 + **Breaking changes**

gap/Parser.gi

@@ -298,8 +298,9 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
           comment_start_pos, context_stack, current_command,
           current_line, current_line_fence, current_line_info,
           current_line_is_fence_delimiter, current_line_positition_for_filter,
-          current_line_unedited, filename, filestream, groupnumber,
-          line_number, markdown_fence, plain_text_mode, rest_of_file_skipped,
+          current_line_unedited, display_filename, filename,
+          filestream, groupnumber, line_number,
+          markdown_fence, plain_text_mode, rest_of_file_skipped,
           scope_group, single_line_title_item_list, title_item,
           title_item_list, xml_comment_mode;
     groupnumber := 0;
@@ -325,11 +326,14 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
     end;
     ErrorWithPos := function(arg)
         local list;
-        list := Concatenation(arg, [ ",\n", "at ", filename, ":", line_number]);
+        list := Concatenation(
+            arg,
+            [ ",\n", "at ", display_filename, ":", line_number ]
+        );
         CallFuncList(Error, list);
     end;
     CurrentSourcePosition := function()
-        return rec( filename := filename, line := line_number );
+        return rec( filename := display_filename, line := line_number );
     end;
     RecordStringSourcePosition := function( item )
         local source_field;
@@ -1220,6 +1224,12 @@ InstallGlobalFunction( AutoDoc_Parser_ReadFiles,
     rest_of_file_skipped := false;
     ##Now read the files.
     for filename in filename_list do
+        if IsString( filename ) then
+            display_filename := filename;
+        else
+            display_filename := filename.display;
+            filename := filename.path;
+        fi;
         Reset();
         ##Need to set autodoc_read_line to false again since we now look at a new file.
         autodoc_read_line := false;

tst/errorwithpos.tst

@@ -1,14 +1,14 @@
 #
 # test parser error reporting with ErrorWithPos
-gap> ParseFixture := function( arg )
+gap> ParseFixture := function( file )
 > local tree, default_chapter_data;
 > tree := DocumentationTree();
-> if Length( arg ) > 1 then
->   default_chapter_data := arg[ 2 ];
-> else
->   default_chapter_data := CreateDefaultChapterData( "Pkg" );
-> fi;
-> AutoDoc_Parser_ReadFiles( [ arg[ 1 ] ], tree, default_chapter_data );
+> default_chapter_data := CreateDefaultChapterData( "Pkg" );
+> file := rec(
+>     path := Filename(DirectoriesPackageLibrary("AutoDoc", ""), file),
+>     display := file
+> );
+> AutoDoc_Parser_ReadFiles( [ file ], tree, default_chapter_data );
 > return tree;
 > end;;
 gap> RenderFixtureDescription := function( file, item_name )

tst/misc.tst

@@ -174,8 +174,36 @@ true
 #
 # AutoDoc_Parser_ReadFiles: multiline InstallMethod parsing
 #
+gap> parser_fixture := rec(
+>     path := Filename(
+>         DirectoriesPackageLibrary("AutoDoc", ""),
+>         "tst/autodoc-parser-installmethod.g"
+>     ),
+>     display := "tst/autodoc-parser-installmethod.g"
+> );;
 gap> tree := DocumentationTree();;
-gap> AutoDoc_Parser_ReadFiles( [ "tst/autodoc-parser-installmethod.g" ], tree, rec() );
+gap> AutoDoc_Parser_ReadFiles( [ parser_fixture ], tree, rec() );
+gap> section := SectionInTree( tree, "Parser", "InstallMethod" );;
+gap> item := section!.content[ 1 ];;
+gap> item!.item_type;
+"Func"
+gap> item!.name;
+"MyOp"
+gap> item!.tester_names;
+"for IsInt,IsString"
+gap> item!.arguments;
+"x,y"
+gap> olddir := Filename(DirectoryCurrent(), "");;
+gap> ChangeDirectoryCurrent(Filename(DirectoryTemporary(), ""));
+true
+gap> tree := DocumentationTree();;
+gap> AutoDoc_Parser_ReadFiles(
+>     [ parser_fixture ],
+>     tree,
+>     rec()
+> );
+gap> ChangeDirectoryCurrent(olddir);
+true
 gap> section := SectionInTree( tree, "Parser", "InstallMethod" );;
 gap> item := section!.content[ 1 ];;
 gap> item!.item_type;