[SCons] Extend coverage option to Python module

.gitignore

@@ -45,5 +45,6 @@ environment.y*
 *.gch
 coverage/
 coverage.info
+.coverage
 doc/sphinx/matlab/*.rst
 !doc/sphinx/matlab/index.rst

interfaces/cython/SConscript

@@ -88,12 +88,17 @@ license = localenv.Command("LICENSE.txt", "#build/ext/LICENSE.txt",
                            Copy("$TARGET", "$SOURCE"))
 localenv.Depends(license, localenv["license_target"])
 
+directives = {}
+if env["coverage"]:
+    directives["linetrace"] = True
+    localenv.Append(CPPDEFINES={"CYTHON_TRACE": 1})
+
 # Build the Python module
 cython_obj = []
 for pyxfile in multi_glob(localenv, "cantera", "pyx"):
     cythonized = localenv.Command(
          f"cantera/{pyxfile.name.replace('.pyx', '.cpp')}", pyxfile,
-         '''${python_cmd} -c "import Cython.Build; Cython.Build.cythonize(r'${SOURCE}')"'''
+         f'''${{python_cmd}} -c "import Cython.Build; Cython.Build.cythonize(r'${{SOURCE}}', compiler_directives={directives!r})"'''
     )
     for pxd in multi_glob(localenv, "cantera", "pxd"):
         localenv.Depends(cythonized, pxd)

test/SConscript

@@ -145,6 +145,8 @@ def addPythonTest(testname, subdir, script, interpreter,
             cmdargs.insert(0, "show_long")
         if env["verbose_tests"]:
             cmdargs.insert(0, "verbose")
+        if env["coverage"]:
+            cmdargs.insert(0, "coverage")
         if env["skip_slow_tests"]:
             environ["CT_SKIP_SLOW"] = "1"
 

test/python/coverage.ini

@@ -0,0 +1,6 @@
+[run]
+plugins = Cython.Coverage
+omit =
+    *.cti
+    stringsource
+source = ../../build/python/cantera

test/python/runCythonTests.py

@@ -38,7 +38,6 @@
 from pathlib import Path
 
 CANTERA_ROOT = Path(__file__).parents[2]
-os.chdir(str(CANTERA_ROOT / "test" / "work"))
 
 try:
     import pytest
@@ -62,6 +61,7 @@
     fast_fail = False
     show_long = False
     verbose = False
+    coverage = False
     if "fast_fail" in sys.argv:
         fast_fail = True
         subset_start += 1
@@ -71,6 +71,9 @@
     if "verbose" in sys.argv:
         verbose = True
         subset_start += 1
+    if "coverage" in sys.argv:
+        coverage = True
+        subset_start += 1
 
     base = CANTERA_ROOT / "test" / "python"
     subsets = []
@@ -85,6 +88,8 @@
         pytest_args += ["--durations=50"]
     if fast_fail:
         pytest_args.insert(0, "-x")
+    if coverage:
+        pytest_args.extend(["--cov=cantera", "--cov-config=test/python/coverage.ini"])
     if verbose:
         pytest_args.insert(0, "-v")
     else: