Can the Soviet Union's ambassador to Washington find happiness as dean of the 135-nation diplomatic corps when some of the ambassadors, technically, do not speak to him?

That's one test ahead for the grand old art of diplomacy, when and if the new government of Nicaragua recalls Ambassador Guillermo Sevilla-Sacasa, an embassy row veteran since 1943 and dean of the corps since 1955. Next in line as Washington's ranking diplomat, with 17 years here is Soviet Ambassador Anatolly F. Dobrynin who automatically becomes dean.

There are some other "tests." For potential irony, amusement or whimsical embarrassment, consider these scenarios:

Dobrynin at a White House welcoming ceremony for a NATO head of state or government;

Dobrynin among the inner circle at the White House reception which follows;

Dobrynin at a White House welcome for a state visitor from Israel, the Ivory Coast, Saudi Arabia or, say, South Africa even though none of those countries has diplomatic ties with the Soviet Union;

Dobrynin among the inner circle at the White House reception later;

Dobrynin representing the corps at the national day celebrations of those countries with whom his nation has no diplomatic ties.

Dobrynin talking the vice dean into substituting in his absence even though the vice dean is the Ivory Coast's Ambassador Timothee Ahoua and, technically, they do not speak.

(Nicaragua and the Soviet Union did not have diplomatic relations, either.)

More than a dozen countries, with envoys here, have no diplomatic ties with the Soviet Union. Diplomats being paragons of tact, there seems little likelihood of trouble head. Still, there is some concern.

"We assume that if Mr. Dobrynin becomes dean he will fulfill his function as leader of the diplomatic corps separately from his function as ambassador of a country with whom we have no ties," said a spokesman for Israeli Ambassador Ephraim Evron.

"And we hope without discrimination."

There is no provision in the Convention of Diplomatic Relations completed in Vienna in 1961 for the election of a dean. There is no way for a dean get out of the job, short of leaving his post - nor any way his colleagues can get him out.

"There is no way to protest," said Richard Gookin, deputy chief of protocol, laying to rest once and for all that possibility.

The dean's functions are largely ceremonial. He is the first in line at a diplomatic reception or dinner given for chiefs of mission by the president or secretary of state. He sits on the right of the president's wife or the wife of the secretary of state. He also is expected to give the responding toast on behalf of the corps.

On more substantive matters, the dean represents the corps when questions of privilege or immunity arise. When Montgomery County recently announced it will charge tuition for some 2,000 children of diplomats attending county schools, Sevilla-Sacasa lodged official protest with the secretary of state that the diplomatic corps is largely exempt from local taxes.

An ambassador's precedence is established by the date he presented his credentials to the president. The dean is the ambassador who managed to outlast his colleagues.

Former Chief of Protocol Henry Catto said Sevilla-Sacasa possessed "endless willingness" to do the day-to-day chores of the dean. "As a practical matter, he was able to because demand on his time from bilateral relations was not overwhelming."

As for Dobrynin, Catto said "he has a man-killing job already."