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CATG is a concolic unit testing engine for Java programs. The implementation uses ASM for instrumentation. ASM instrumentation instruments (see janala.instrument.) class files at runtime and dumps (see janala.logger.) to a file a log of all instructions executed by the program and all values loaded from local stacks and heaps. A concolic execution engine (see janala.interpreters.*) then takes the log and performs both symbolic and concrete interpretation of the logged instructions.

You must have java, gradle, cvc4 (, and python 2.7 in your PATH. Two extra jar files are needed to run the tool. Create a lib directory in the root directory and download the following jar files

place them in the lib directory. Then invoke

gradle build


gradle integrationTest

To run the the full integration tests, use

./  # This builds CATG and copy it to lib/

To run tests and see coverage report, use

gradle build
gradle jacocoTestReport

This runs the tests using online concolic execution. To run tests with offline concolic execution, use

python --offline

If you want to generate tests on a Java class file having a main method, you need to use the script. For example, the following command generates test inputs for the class tests.Testme (the java source of this class can be found in src/integration/java/tests/

python --coverage 100 tests.Testme


python janala/ -h usage: [-h] [--offline] [-v] [-c] [-D D] maxIterations className [arguments [arguments ...]]

positional arguments:

maxIterations   Maximum number of times the program under test can be
className       Java class to be tested.
arguments       Arguments passed to the program under test.

optional arguments:

-h, --help      show this help message and exit
--offline       Perform concolic testing offline. An intermediate trace file
              is generated during the execution of the program. offilne
              mode results in 2X slowdown that non-offline mode
-v, --verbose   Print commands that are executed.
-c, --coverage  Compute detailed coverage by rerunning tests.
-D D            JVM options


a concolic testing engine for Java








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