Johnny DeLaine said he has been "cruising" through Hampton University for three years, fully expecting to be teaching elementary school after he graduates next spring. But at his first interview for a teaching job a few weeks ago, he woke up to a frightening realization: Four years of college could go down the drain if he fails a test mandated for new Virginia teachers next year.

"In that interview, he talked on and on about testing . . . ," said DeLaine. "My whole career is riding on it."

DeLaine, 20, who has earned mostly Bs and Cs in the small college near Norfolk, will be in the first class of prospective teachers required to pass the National Teachers Exam in order to be certified in Virginia after July 1986.

Maryland school officials said they expect that a test will be approved there next year. And in the District of Columbia, where the national examination was abandoned in the late 1960s, officials are considering reinstating subject matter tests for new teachers.

The call for teacher testing here is an echo of the national cry for educational excellence. It is a movement that has led parents, legislative bodies and school administrators, who are alarmed at what they see as declining standards, to seek guarantees of competence.

To the growing list of such measures -- minimum competency, basic skills and graduation tests for students -- states across the country are adding precertification exams for teachers. Twenty-five states have passed such a requirement, including 17 that have gone into effect since 1982.

"It's just a way of making sure someone has the knowledge base you want them to have to go into the classroom," said Robby Champion, a specialist in teacher education with the Maryland Department of Education. Those who do not pass, she said, "will either have to get more background or they're going to have to find something else to do."

In most states, the tests are designed to measure competency in communications skills, general knowledge of literature, math and other basic subjects, and knowledge about the teaching profession. Teacher candidates are also often required to take proficiency exams in their area of specialization.

The testing requirement has both friends and enemies among the ranks of teachers, administrators and unions. Proponents, for example, argue that it is only reasonable to subject the field to the same hurdles faced by other professions, such as lawyers, doctors and accountants. Testing, they say, will end the horror stories about teachers who cannot spell or add.

But opponents of the requirement argue vociferously that the test is unnecessary, that it does not measure the range of teaching skills and that it will cut deeply into the ranks of minority teachers.

"It's hard to imagine that an 80-minute test could invalidate four years of college," said Solomon Kendrick, director of certification and accreditation for the D.C. public schools. The District dropped its testing requirement, he said, after administrators discovered that there was little difference in the classroom success of teachers who passed the test and those who did not, but were hired anyway on a temporary basis.

Students facing the test, and many teachers in the field, agree with Kendrick.

"I feel it's not really right," said DeLaine, who has wanted to be a teacher since his high school days in Alexandria. "That test is not indicative of how my actual skills are. But the fact remains, I have to put aside my personal feelings and pass the test."

Marge Psaltis, a vocational education teacher at Fairmont Heights High School in Prince George's County, said the tests are unnecessary. "Most professional teachers have been through four years of college," she said.

"Throughout college we've been tested and tested and tested, and then observed and evaluated. By the time we've done all this, we are professional teachers, and a professional person does not need to be tested."

While some jurisdictions, such as the District, tested teachers as long ago as the 1950s, the national momentum is much more recent and is tied closely to widespread impressions that public education in this country has been on the decline.

Parents and public officials decrying the quality of education have cited, among other evidence, lower SAT scores for college students in teacher education programs. Students who indicated they wanted to become teachers when the SATs were given in June 1984, for example, scored 28 points below the mean in the verbal portion of the test and 46 points below the mean in mathematics, according to the Educational Testing Service, which compiles the exam.

In response, many state legislatures and school boards have mandated the certification tests. "They felt a stronger quality control system needed to be instituted . . . assuring the public there were standards that attracted and retained the best people in the classroom," said Wendell Hylton, a special assistant in the Virginia Department of Education.

Added to this was the realization that, as the need for teachers grew with public school enrollment in the 1980s, school systems may be tempted to lower their standards in order to fill vacancies.

"Many of the reports project that by 1990 or 2000 we will have a different supply-and-demand situation, and as that happens, and we take in larger quantities of people, we need to make certain they are the quality we want," said Herman Behling, assistant superintendent of schools in Maryland.

In most states, teachers already in the field have not been required to take a test. For prospective teachers, however, the issue is very practical -- if they can't pass, they can't teach.

DeLaine and many of his classmates at the predominantly black Hampton University face an added pressure: Minority students have failed the test at much higher rates than their white counterparts.

"Everybody is not a good test-taker," said Darlene Clayton, a classmate of DeLaine. "We already have the attitude that so many blacks have failed."

In tests taken in Virginia since 1980 as a lead-in to the mandated program next year, 56 percent of the students from historically black colleges have failed the communication skills portion of the national exam, compared with 6 percent of the students from historically white schools, according to state officials. On the general knowledge section of the test, students from black schools have failed at a rate of 45 percent, compared with 3 percent among students from white schools.

"Absolutely, the tests will reduce the number of black and minority teachers in this country," said Mary E. Dilworth, a researcher at Howard University's Institute for the Study of Educational Policy. Dilworth, who wrote a report on teacher certification issues in 1984, said teacher testing is a "quick fix," often mandated for political reasons by state legislatures eager to please vocal constituencies. But she expects that the performance of blacks will improve as they get more experienced with test-taking.

Lawrence Cross, who headed a study on the test for the Virginia Board of Education, said that black students, particularly in Virginia, are not doing as well on the test because of longstanding inequity in the schools they attend.

"I don't think the test is discriminatory; I think our society is discriminatory," he said. "What is reflected is the heritage of the separate-but-equal policy in Virginia for too many years."

The issue is also being raised in Maryland. Freeman Hrabowski, vice president for academic affairs at the predominantly black Coppin State College, argued that public funding should be made available to improve teacher education programs at historically black schools.

"It is not unreasonable to use standardized tests as a criterion for eligibility for certification," he said. "However, as we move to have more accountability in public education, it will be very important for governmental agencies, foundations and others to provide funds necessary to ensure minorities are not placed at a significant disadvantage."

In Maryland, where Prince George's and Montgomery counties already require a basic skills test, the proposal for a statewide exam came from a special commission appointed by the Board of Education. The test recommended by the commission was the National Teachers Exam, some or all of which is required for certification in 13 states. Sometime this summer, the state board is expected to decide whether to approve the national exam or look for another test.

In the meantime, the Maryland State Teachers Association has given its approval, with qualification. "We're not going to fight this. Obviously, we want our professional peers to be well trained," said Janice Piccinini, its president.

But among the union's recommendations for the test is a unique stipulation that the state pay to re-educate students who graduate from a state-approved education program but fail the test. "That student has become the victim of an incompetent program," she said.

Nationally, teacher unions have taken a vocal position. Opposition has gained national attention in Arkansas, where both new and certified teachers must pass a test.

The National Education Association, while calling for tougher standards in teacher education programs, has historically opposed a single "paper and pencil" test requirement for certification.

Albert Shanker, president of the American Federation of Teachers, has, on the other hand, proposed that a rigorous exam be instituted for new teachers and administered by an independent board.

"We think most of those tests in use are a joke. The subject matter tests are about a sixth or seventh grade level," said AFT spokeswoman Bella Rosenberg. "Bright people don't want to go into something where the message is, 'We don't care.' They want to be part of a challenging thing, where there are some hurdles."