West German resolve on terrorism being put to the test. HAMADEI TRIAL

The trial of Abbas Ali Hamadei in D"usseldorf and the murder of a West German consular official in Paris this week are testing West German skill and resolve in dealing with international terrorism. Mr. Hamadei, a naturalized West German originally from Lebanon, appeared in court Tuesday on charges of smuggling explosives, participating in the kidnapping in Lebanon a year ago of two West German businessmen, and trying to extort the Bonn government into not extraditing his younger brother, Mohammed Ali Hamadei, to the United States.

The US has been seeking the younger Hamadei's extradition on murder charges ever since discovering that his fingerprints matched those in the TWA airliner hijacked from Athens to Beirut in 1985.

In Paris, West German consular official Siegfried Wielsp"utz was shot and killed early Monday on a bridge over the Seine. A leaflet from the Kurdistan National Liberation Front (ERNK) was found in his jacket.

The older Hamadei has denied charges against him, and minutes before the trial opened, his lawyer appealed in Hamadei's name to the Mideast abductors to release remaining West German hostage Rudolf Cordes.

The kidnappers have explicitly linked themselves to the Hamadeis, however. They asserted in an open letter Monday that their treatment of Mr. Cordes would depend on the outcome of the older brother's trial. Yesterday they told the Associated Press the younger brother was being mistreated in jail. The West German government denied the charge. The second West German hostage, Alfred Schmidt, was released a few months ago, reportedly for a $1 million ransom. This, too, has been denied by the government.

Abbas Ali Hamadei is the ``small fry'' of the two brothers in West German custody. It is expected that the older brother, the bigger fish, will be indicted in the next few weeks. He was arrested a year ago in the Frankfurt airport in possession of liquid explosives.

Immediately after Mohammed Ali Hamadei's arrest the two West Germans were kidnapped in Lebanon, with the demand that Hamadei not be extradited. A few days later West German police arrested Abbas Ali Hamadei as he returned to Frankfurt on a flight from Beirut. Last summer West Germany decided against extradition of the younger Hamadei in favor of trying him here on hijacking and murder as well as lesser charges.

Middle East politics may also have figured in the Paris murder of Wielsp"utz, though Kurdish spokesmen have denied any association with the killing. Several hundred thousand Kurds work here, and various nationalist groups have been in conflict with the Bonn government since police in Cologne seized 700,000 marks from Kurdish activists in an investigation last summer.

The US is watching closely to see how the West German judicial system will handle Mohammed Ali Hamadei. Various US officials have expressed disappointment at Bonn's decision not to extradite him and worry that Bonn might weaken and negotiate with Mideast hostage-takers to free Cordes.