1. A method, comprising: identifying a fix defining a plurality of unique changes to a computer program; applying the fix, including the plurality of unique changes, to the computer program to generate a test version of the computer program and, as each of the plurality of unique changes is applied, identifying, in real time using a processor, program code units in the computer program changed by the unique changes and generating corresponding data entries in a first data structure; determining a number of test cases available to test the program code units in the computer program changed by the unique changes by accessing the data entries in the first data structure and matching, using the processor, each of the program code units to corresponding data entries contained in a second data structure that correlates program code units to test cases; responsive to determining the number of test cases available to test the program code units in the computer program changed by the unique changes, automatically generating, using the processor, a test readiness index indicating a readiness of the fix to be tested, the test readiness index based on a number of unique changes to the computer program defined by the fix and the number of test cases available to test the unique changes to the computer program defined by the fix; and outputting the test readiness index.