///|
/// A compact, valid IFC4 fixture used by examples and regression tests.
pub fn minimal_fixture() -> String {
  let source : String =
    #|ISO-10303-21;
    #|HEADER;
    #|FILE_DESCRIPTION(('ViewDefinition [CoordinationView]'),'2;1');
    #|FILE_NAME('minimal.ifc','2026-08-17T00:00:00',('moonbit-ifc'),(''),'moonbit-ifc','moonbit-ifc','');
    #|FILE_SCHEMA(('IFC4'));
    #|ENDSEC;
    #|DATA;
    #|#1=IFCPROJECT('0000000000000000000000',#2,'Demo project',$,$,$,$,(#10),#11);
    #|#2=IFCOWNERHISTORY($,$,$,.ADDED.,$,$,$,0);
    #|#10=IFCUNITASSIGNMENT((#12));
    #|#11=IFCCONTEXT($,'Model','ViewDefinition [CoordinationView]','',#13,$,$,(#14),$);
    #|#12=IFCSIUNIT(*,.LENGTHUNIT.,$,.METRE.);
    #|#13=IFCAXIS2PLACEMENT3D(#15,$,$);
    #|#14=IFCGEOMETRICREPRESENTATIONCONTEXT($,'Model',3,1.0E-05,#13,$);
    #|#15=IFCCARTESIANPOINT((0.0,0.0,0.0));
    #|#20=IFCBUILDINGSTOREY('storey000000000000000000',#2,'Ground floor',$,$,#21,$,$,.ELEMENT.,0.0);
    #|#21=IFCLOCALPLACEMENT($,#22);
    #|#22=IFCAXIS2PLACEMENT3D(#15,$,$);
    #|#30=IFCWALL('wall00000000000000000000',#2,'North wall','Example wall',$,#31,#40,'W-01');
    #|#31=IFCLOCALPLACEMENT(#21,#22);
    #|#40=IFCPRODUCTDEFINITIONSHAPE($,$,(#41));
    #|#41=IFCSHAPEREPRESENTATION(#14,'Body','SweptSolid',(#42));
    #|#42=IFCEXTRUDEDAREASOLID(#43,#22,#44,3.0);
    #|#43=IFCRECTANGLEPROFILEDEF(.AREA.,'Wall profile',$,0.2,3.0);
    #|#44=IFCDIRECTION((0.0,0.0,1.0));
    #|#50=IFCRELCONTAINEDINSPATIALSTRUCTURE('rel00000000000000000000',#2,$,$,(#30),#20);
    #|#51=IFCRELAGGREGATES('agg00000000000000000000',#2,$,$,(#20),#1);
    #|#60=IFCPROPERTYSET('pset0000000000000000000',#2,'Pset_WallCommon',$,(#61,#62));
    #|#61=IFCPROPERTYSINGLEVALUE('IsExternal',$,.TRUE.,$);
    #|#62=IFCPROPERTYSINGLEVALUE('Reference',$,IFCLABEL('W-01'),$);
    #|#70=IFCRELDEFINESBYPROPERTIES('prop000000000000000000',#2,$,$,(#30),#60);
    #|ENDSEC;
    #|END-ISO-10303-21;
    #|
  source
}