Spec is a framework in Pharo for describing user interfaces.
Spec is included in any regular Pharo image.
It is possible to load the latest version executing following script:
Metacello new
repository: 'github://pharo-spec/Spec';
baseline: 'Spec2';
onConflict: [ :e | e useIncoming ];
onUpgrade: [ :e | e useIncoming ];
ignoreImage;
load