Do not ignore #@ comments after empty line at start of test file

lib/test.gi

@@ -93,8 +93,9 @@ InstallGlobalFunction(ParseTestInput, function(str, ignorecomments, fnam)
  i := i+1;
  else
  Add(inp, "\n");
+ Add(pos, i);
  i := i+1;
- while i <= Length(lines) and (Length(lines[i]) = 0 or lines[i][1] = '#') do
+ while i <= Length(lines) and (Length(lines[i]) = 0 or (StartsWith(lines[i], "#") and not StartsWith(lines[i], "#@"))) do
  i := i+1;
  od;
  Add(outp, JoinStringsWithSeparator(lines{[1..i-1]}, "\n"));

tst/testspecial/broken-test.g.out

@@ -1,47 +1,47 @@
 gap> Test("broken-test-2.tst", rec(width := 800));
 Error, Invalid test file: #@ command found in the middle of a single test at broken-test-2.tst:5 at GAPROOT/lib/test.gi:31 called from
-testError( "Invalid test file: #@ command found in the middle of a single test" ); at GAPROOT/lib/test.gi:131 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+testError( "Invalid test file: #@ command found in the middle of a single test" ); at GAPROOT/lib/test.gi:132 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop
 brk> quit;
 gap> Test("broken-test-3.tst", rec(width := 800));
 Error, Invalid test file at broken-test-3.tst:5 at GAPROOT/lib/test.gi:31 called from
-testError( "Invalid test file" ); at GAPROOT/lib/test.gi:137 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+testError( "Invalid test file" ); at GAPROOT/lib/test.gi:138 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop
 brk> quit;
 gap> Test("broken-test-4.tst", rec(width := 800));
 Error, Invalid test file: Nested #@if at broken-test-4.tst:2 at GAPROOT/lib/test.gi:31 called from
 testError( "Invalid test file: Nested #@if" ); at GAPROOT/lib/test.gi:52 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop
 brk> quit;
 gap> Test("broken-test-5.tst", rec(width := 800));
 Error, Invalid test file: two #@else at broken-test-5.tst:7 at GAPROOT/lib/test.gi:31 called from
 testError( "Invalid test file: two #@else" ); at GAPROOT/lib/test.gi:63 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop
 brk> quit;
 gap> Test("broken-test-6.tst", rec(width := 800));
 Error, Invalid test file: Continuation prompt '> ' followed by a tab, expected a regular space at broken-test-6.tst:3 at GAPROOT/lib/test.gi:31 called from
-testError( "Invalid test file: Continuation prompt '> ' followed by a tab, expected a regular space" ); at GAPROOT/lib/test.gi:128 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+testError( "Invalid test file: Continuation prompt '> ' followed by a tab, expected a regular space" ); at GAPROOT/lib/test.gi:129 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop
 brk> quit;
 gap> Test("invalidtestfile.tst", rec(width := 800));
 Error, Invalid test file at invalidtestfile.tst:7 at GAPROOT/lib/test.gi:31 called from
-testError( "Invalid test file" ); at GAPROOT/lib/test.gi:137 called from
-ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:571 called from
+testError( "Invalid test file" ); at GAPROOT/lib/test.gi:138 called from
+ParseTestInput( full, opts.ignoreComments, fnam ) at GAPROOT/lib/test.gi:572 called from
 <function "Test">( <arguments> )
  called from read-eval loop at *stdin*:2
 type 'quit;' to quit to outer loop

tst/testspecial/leading-empty-line.g

@@ -0,0 +1 @@
+Test("leading-empty-line.tst", rec(width := 800, ignoreComments := false));

tst/testspecial/leading-empty-line.g.out

@@ -0,0 +1,10 @@
+gap> Test("leading-empty-line.tst", rec(width := 800, ignoreComments := false));
+########> Diff in leading-empty-line.tst:1
+# Input is:
+
+# Expected output:
+
+# But found:
+########
+false
+gap> QUIT;

tst/testspecial/leading-empty-line.tst

@@ -0,0 +1,5 @@
+
+#@if true
+gap> 1 + 1;
+2
+#@fi