如何测量 C++ 中执行部分的代码覆盖率

Question

I have two C++ binaries (A and B) with socket connections between two binaries.
Binary A is listening for B. And, B connects to the A.

A accepts B's message and executes some functions depending on message contents.
We created a kind of unit-test to test various message types.

From these tests, I would like to measure A's executed line from our test messages.
I searched for tools to measure code coverage, and I found lcov .

However, lcov measured total executed lines of code including initialization and other useless chunks.
I may create a new code to test functionality without socket connection.
But the code structure is complex, so it takes very long time to implement tests.

So, I would like to skip those lines in lcov to obtain purely executed lines caused by our test messages .

If it is impossible and there is a better tool for this situation, please recommend suitable tools to measure this.

Thanks.

Answer 1

Call __gcov_reset before your testcases to discard the data collected from initialization.

Answer 2

It is important to understand that "coverage" is a set of source code locations. You can do "arithmetic" on sets: union ("add"), complement, difference ("subtract").

The key is to get a tool that will (set)subtract test coverage data sets.

Then you collect test coverage for starting/stopping your program. This covers initialization and setup. Call this set I.

Now collect test coverage for your program executing the activities of interest, eg, the "communication" part. Call this set X.

What you want is the set computed by subtracting I from X: "XI" in set notation.

This means you need a tool that will let you collect these sets and do this computation.

I'm sure you can collect X and I with lcov. But I don't think lcov gives you a way to compute the set difference. If it does, bingo, you're in business.

If it doesn't, you might consider using my company's test coverage tools. They provide an explicit means to collect test coverage sets, and do arbitrary set computations, eg, set unions, set complements, set differencing, in the user interface. You don't need to change your code to do this.

See http://www.semdesigns.com/Products/TestCoverage/