Exec Analyzer

Running ExecAnalyzer utility to parse the jacoco.exec file

Help Menu

tacoco$ mvn -q exec:java -Panalyzer -Dtacoco.help

Tacoco: Exec-file Analyzer
usage: mvn exec:java -q -Panalyzer [arguments] 

Arguments:
-Dtacoco.sut=<dir>                  (Required) Absolute-path of system-
                                    under-test's root.
-Dtacoco.exec=<*.exec>              (Required) Absolute-path of input exec
                                    binary.
-Dtacoco.json=<*.json>              (Default: STDOUT) Absolute-path of per-test
                                    coverage output.
-Dtacoco.fmt=<LOOSE|COMPACT|DENSE>  (Default: DENSE) Compression format of
                                    coverage data.
-Dtacoco.pp                         Pretty prints coverage data to json file.
-Dtacoco.help                       Prints this message and exits (with 0).

Step-wise instructions

1. Compile the ExecAnalyzer as stated above.
2. Use the mvn command on the command line to execute the ExecAnalyzer as shown above in the help menu, e.g.: mvn exec:java -q -Panalyzer -Dtacoco.sut=/home/vijay/misc_Programming/pmd/pmd-java -Dtacoco.json=pmd-java-compact.json -Dtacoco.exec=jacoco.exec -Dtacoco.pp -Dtacoco.fmt=COMPACT
   • -Dtacoco.pp and -Dtacoco.help are treated as flags.
   • -Dtacoco.json=[*.json] and Dtacoco.fmt=[LOOSE|COMPACT|DENSE]. Not specifying those options will result in the selection of default options for each of those arguments.
   • The default options are:
     • -Dtacoco.json=[*.json] -- System.out i.e. Standard-Out
     • -Dtacoco.fmt=[LOOSE|COMPACT|DENSE] -- DENSE
   • -Dtacoco.pp, being a flag, is also optional. Not providing it means that you do not want pretty-printed coverage-data.
3. NOTE: Coverage Compression Formats and Pretty-printing are two different things. Pretty-printing simply ensures that the Json output is printed in a non-minified manner. Continue reading to learn more about coverage compression formats.

Notes on Line-coverage Compression Formats

You have 3 choices for -Dtacoco.fmt=: LOOSE, COMPACT, DENSE

LOOSE Format

• This is a space-inefficient formatting of the coverage information.

COMPACT Format

• Bit-based encoding for each line-level coverage information.
• Line-level coverage information encoded to single 32-bit int.
• Each (source) line has the following two counters:
  • Bytecode Instruction Coverage Counter (number of bytecode instructions covered and missed)
  • Branch Coverage Counter (number of branches covered and missed)
• Compression Scheme is as follows:
  • (starting from the most significant bits)
  • First 8 bits encode number of bytecode instructions covered,
  • Next 8 bits encode number of bytecode instructions missed,
  • Next 8 bits encode number of branches covered,
  • Next 8 bits encode number of branches missed.
• Assuming: each line contains max 255 bytecode instructions or branches.

DENSE Format

• Only the statuses of the lines i.e. EMPTY, NOT_COVERED, PARTLY_COVERED, FULLY_COVERED are encoded in DENSE formatting.
• 2 bits are used per line for each line status: EMPTY=00, NOT_COVERED=01, PARTLY_COVERED=11, FULLY_COVERED=10.
• Instruction and Branch counters are disregarded in DENSE formatting.
• DENSE formatting encodes 16 (at most) line-statuses into a single 32-bit integer.
• DENSE formatting is implemented in LinesStatusCoder.

Running CoverageJsonReader

tacoco$ mvn -q exec:java -Preader -Dtacoco.help

Tacoco: Coverage Json-file Reader
usage: mvn exec:java -q -Preader [arguments] 

Arguments:
-Dtacoco.json=<*.json>  (Required) Absolute-path of per-test coverage file.
-Dtacoco.out=<*.json>   Absolute-path of per-sourcefile coverage matrix.
-Dtacoco.pp             Pretty prints coverage data to json file.
-Dtacoco.help           Prints this message and exits (with 0).

1. Use the following maven command on the command line to execute the CoverageJsonReader: mvn exec:java -Preader -Dtacoco.json="/path/to/your/json/coverage-data-file.json"

Space Optimized Coverage Matrix

Per source file Coverage matrix

• The coverage matrix for a project is split into smaller coverage matrices for each source file.
• The statements in this matrix are localized to only the statements in the sourcefile in question.
• We maintain a list of tests for which the test-statement matrix is built.
• Tests that do not execute a single statement in the sourcefile are considered IRRELEVANT and are not a part of the test-statement matrix.
• Check org.spideruci.tacoco.coverage.CoverageMatrix2 and org.spideruci.tacoco.coverage.SourceSpecificCoverageMatrix to study the models for per-source coverage.
• More to come ...
  • converting the boolean arrays into bit arrays/vectors
  • (optional) including an index to the test-case names. currently only the test-case-ids are listed in the per-source-coverage-matrices.