Painter, decorator, furniture designer and Italian actress, she was born in Milan but graduated from the Accademia delle Belle Arti in Bologna.
In 1928 she married the painter Carlo Vittorio Testi, moving to Rome where she began working with Maria Monaci Gallenga in the auction house and boutique in Via Veneto in Rome and the Boutique Italianne in Paris, creating furniture items and clothing in a futuristic style.
She enthusiastically adopted the "Secondo Futurismo" and became a celebrity, with paintings that gained her international fame, especially aero painting which gave her a personal stylistic imprint. Fides Testi was talked about in numerous magazines and in books.
In 1933 she participated in the Mostra Nazionale di Arte Futurista I and at the Milan Triennale. In 1934 she held her first solo exhibition at the Casa d'Arte Bragaglia and participated in the Venice Biennale XIX and in the Futurist Aero Painters section in the second Mostra Internazionale di Arte coloniale in Naples. In 1935, she was at the Rome Quadriennale II and in 1936 she was again present in the Milan Triennale and the Venice Biennale XX and signed La plastica murale futurista manifesto.
At the urging of her second husband, she abandoned Futurism in 1937 and devoted herself to figurative painting. In the 1950s she opened the Galleria d'Arte Stagni in Rome and published "Il Vento" and "Dea Film" magazines with her own poems, articles and essays.
In the 60s and 70s she played minor roles in various Pasolini and Fellini films and in the 80s she resumed aero painting.
She died in Rome in 2002 aged ninety-eight.