Using eclipse find and replace all to swap arguments
use the following regexp to find:
assertEquals\((.*),(.*)\);
and this replacement value:
assertEquals(\2,\1);
The regexp means "assertEquals( followed by a first group of chars followed by a comma followed by a second group of chars followed by );".
The replacement value means "assertEquals( followed by the second group of chars found followed by a comma followed by the first group of chars found followed by );".