preg_match匹配模式，其中带有星号（*）

preg_match('/te**ed/i', 'tested', $matches);

gives me the following error:

ERROR: nothing to repeat at offset 3

What do I do to allow the pattern to actually contain *?

To use literal asterisks you have to escape them with backslashes. To match the literal te**ed you would use an expression like this:

preg_match('/te\*\*ed/i', 'tested', $matches); // no match (te**ed != tested)

But I doubt this is what you wanted. If you mean, match any character, you need to use .:

preg_match('/te..ed/is', 'tested', $matches); // match

If you really want any two lower case letter, then this expression:

preg_match('/te[a-z]{2}ed/i', 'tested', $matches); // match

Putting a backslash before any character wil tell PHP that the character should be taken as is, not as a special regex character. So:

preg_match('/te\\**ed/i', 'tested', $matches);

If you want to use asterisk-like search, you can use next function:

function match_string($pattern, $str)
{
  $pattern = preg_replace('/([^*])/e', 'preg_quote("$1", "/")', $pattern);
  $pattern = str_replace('*', '.*', $pattern);
  return (bool) preg_match('/^' . $pattern . '$/i', $str);
}

Example:

match_string("*world*","hello world") // returns true
match_string("world*","hello world") // returns false
match_string("*world","hello world") // returns true
match_string("world*","hello world") // returns false
match_string("*ello*w*","hello world") // returns true
match_string("*w*o*r*l*d*","hello world") // returns true

Improving upon Viktor Kruglikov's answer, this is the PHP 7.3 way of doing such a thing:

private function match(string $pattern, string $target): bool
{
    $pattern = preg_replace_callback('/([^*])/', function($m) {return preg_quote($m[0], '/');}, $pattern);
    $pattern = str_replace('*', '.*', $pattern);
    return (bool) preg_match('/^' . $pattern . '$/i', $target);
}