1. A non-transitory computer-readable recording medium having stored therein a test program that causes a computer to execute a process comprising: starting a test of a test-target program containing a plurality of modules by executing a plurality of individual tests, the plurality of individual tests being respectively associated with the plurality of modules; generating test-relationships information that includes relationships between the plurality of individual tests based on module-relationships information including relationships of the plurality of modules; and specifying one or a plurality of additionally executing tests based on the test-relationships information when a test result indicates at least one of the plurality of individual tests has been abnormally completed, wherein the test-relationships information is updated based on a test result of an individual test among the plurality of individual tests, the test-relationships information is a probability of, or an accumulated number of, execution results indicating the individual tests respectively associated with the plurality of the modules which have been concurrently abnormally completed, and the test-relationships information is updated based on a test result of an individual test associated with a module executed for the test-target program and a test result of an individual test associated with another module associated with the module.