Nadiya Savchenko's high-profile case has raised deep concern in the West and in Kiev, where the government denounced the trial as a "farce" and demanded her immediate release.
"I will continue my dry hunger strike," the 34-year-old said in her final address to the court in the small Russian town of Donetsk.
The Iraq war veteran, who has been held by Russia since June 2014, first announced her protest action last Thursday, rejecting both food and water.
"Maybe I will live that long," Savchenko declared.
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The judge said the verdict would be handed down on March 21 and 22.
"Here's my final word," Savchenko said, climbing onto a bench in her glass enclosure and raising her middle finger in a defiant gesture at the judge and prosecution.
Refusing both food and water is known in Russia as a "dry hunger strike" and was a method of last resort for some Soviet dissidents under Communism.
The prosecution has sought a 23-year jail sentence for Savchenko over the killing of two journalists from Russian public broadcaster VGTRK in shelling in Ukraine's eastern Lugansk region in June, two months after the pro-Russia uprising began.