Add test for pyproject.toml loading without explicit --cov-config. Ref …

…#508.

tests/test_pytest_cov.py

@@ -1365,6 +1365,13 @@ def test_basic(no_cover):
 exclude_lines =
     raise NotImplementedError
 """
+PYPROJECTTOML = """
+[tool.coverage.report]
+# Regexes for lines to exclude from consideration
+exclude_lines = [
+    'raise NotImplementedError',
+]
+"""
 
 EXCLUDED_TEST = """
 
@@ -1388,6 +1395,14 @@ def test_coveragerc(testdir):
     result.stdout.fnmatch_lines([f'test_coveragerc* {EXCLUDED_RESULT}'])
 
 
+def test_pyproject_toml(testdir):
+    testdir.makefile('.toml', pyproject=PYPROJECTTOML)
+    script = testdir.makepyfile(EXCLUDED_TEST)
+    result = testdir.runpytest('-v', f'--cov={script.dirpath()}', '--cov-report=term-missing', script)
+    assert result.ret == 0
+    result.stdout.fnmatch_lines([f'test_pyproject_toml* {EXCLUDED_RESULT}'])
+
+
 @pytest.mark.skipif('sys.platform == "win32" and platform.python_implementation() == "PyPy"')
 def test_coveragerc_dist(testdir):
     testdir.makefile('', coveragerc=COVERAGERC)