1. A computer-implemented method comprising: obtaining a first test result vector corresponding to a first set of test patterns applied to a first design under test, wherein the first test result vector indicates coverage of one or more events triggered by the first set of test patterns; obtaining a second test result vector corresponding to a second set of test patterns applied to a second design under test, wherein the second test result vector indicates coverage of one or more events triggered by the second set of test patterns and wherein the one or more events triggered by the second set of test patterns includes one or more of the one or more events triggered by the first set of test patterns; and merging coverage data from at least the first test result vector and the second test result vector to obtain a merged event coverage vector, wherein the merged event coverage vector has a length that is less than a sum of lengths of the first test result vector and the second test result vector and wherein the merged event coverage vector indicates coverage of events triggered by at least the first set of test patterns and the second set of test patterns, and wherein the merged event coverage vector contains a plurality of entries and each of the plurality of entries is a value representing whether a corresponding event was covered.