The PostgreSQL source code can be compiled with coverage testing
    instrumentation, so that it becomes possible to examine which
    parts of the code are covered by the regression tests or any other
    test suite that is run with the code.  This is currently supported
    when compiling with GCC, and it requires the gcov
    and lcov packages.
   
A typical workflow looks like this:
./configure --enable-coverage ... OTHER OPTIONS ... make make check # or other test suite make coverage-html
     Then point your HTML browser
     to coverage/index.html.
    
     If you don't have lcov or prefer text output over an
     HTML report, you can run
make coverage
     instead of make coverage-html, which will
     produce .gcov output files for each source file
     relevant to the test.  (make coverage and make
     coverage-html will overwrite each other's files, so mixing them
     might be confusing.)
    
You can run several different tests before making the coverage report; the execution counts will accumulate. If you want to reset the execution counts between test runs, run:
make coverage-clean
     You can run the make coverage-html or make
     coverage command in a subdirectory if you want a coverage
     report for only a portion of the code tree.
    
     Use make distclean to clean up when done.
    
A typical workflow looks like this:
meson setup -Db_coverage=true ... OTHER OPTIONS ... builddir/ meson compile -C builddir/ meson test -C builddir/ cd builddir/ ninja coverage-html
     Then point your HTML browser
     to ./meson-logs/coveragereport/index.html.
    
You can run several different tests before making the coverage report; the execution counts will accumulate.