cov4 test environment

.travis.yml

@@ -16,6 +16,11 @@ matrix:
       name: "Python 3.8 core tests"
       env: TOXENV=py38
 
+    # specific checks for coverage v4 support, coverage v5 is used by default elsewhere
+    - python: "3.8"
+      name: "Python 3.8 coverage v4 tests"
+      env: TOXENV=cov4
+
     # run pre-commit hooks checks
     # TODO: Python 3.8, pyenv global system 3.8 doesn't appear to work
     - python: "3.7"

pytest.ini

@@ -3,3 +3,4 @@ addopts = -ra -v --cov=mutatest
 
 markers =
     slow: slow tests, usually because pytest is running sub-trials on mutated temp caches.
+    coverage: tests that create mock coverage files for running Coverage v4 vs. v5 tests.

tests/conftest.py

@@ -94,22 +94,18 @@ def write_cov_file(line_data: Dict[str, List[int]], fname: str) -> None:
 
     Returns:
         None
-
-    Raises:
-        EnvironmentError: if Coverage version is not 4 or 5
     """
     if coverage.version_info[0] == 4:
         covdata = coverage.CoverageData()
         covdata.add_lines(line_data)
         covdata.write_file(fname)
 
-    if coverage.version_info[0] == 5:
+    else:
+        # assume coverage v 5
         covdata = coverage.CoverageData(basename=fname)
         covdata.add_lines(line_data)
         covdata.write()
 
-    raise EnvironmentError(f"Coverage version is not supported: {coverage.version_info}")
-
 
 ####################################################################################################
 # FILTERS: MOCK COVERAGE FILE FIXTURES

tests/test_api.py

@@ -106,7 +106,7 @@ def test_mutate_ValueError_target(binop_file, mock_LocIdx):
         _ = genome.mutate(target_idx=mock_LocIdx, mutation_op=ast.Div, write_cache=False)
 
 
-@pytest.mark.skipif(coverage.version_info[0] > 4, reason="Coverage version > 4.x")
+@pytest.mark.coverage
 @pytest.mark.parametrize("filter_codes", [set(), ("bn",)], ids=["Filter Empty Set", "Filter BinOp"])
 def test_covered_targets(filter_codes, binop_file, mock_binop_coverage_file):
     """Mock coverage file sets lines 6 and 10 (not 15) to be covered."""
@@ -253,7 +253,7 @@ def test_GenomeGroup_add_folder_with_exclusions(tmp_path):
     assert list(ggrp.keys())[0].name == expected
 
 
-@pytest.mark.skipif(coverage.version_info[0] > 4, reason="Coverage version > 4.x")
+@pytest.mark.coverage
 @pytest.mark.parametrize("filter_codes", [set(), ("bn",)], ids=["Filter Empty Set", "Filter BinOp"])
 def test_GenomeGroup_covered_targets(filter_codes, binop_file, mock_binop_coverage_file):
     """Mock coverage file sets lines 6 and 10 (not 15) to be covered."""

tests/test_filters.py

@@ -34,6 +34,7 @@ def test_unset_coverage_file(fn):
         _ = ccf.coverage_data
 
 
+@pytest.mark.coverage
 @pytest.mark.parametrize(
     "invert, expected",
     [(False, [1, 2, 4]), (True, [3, 5])],

tox.ini

@@ -1,9 +1,10 @@
 [tox]
 minversion = 3.7
-envlist = py37, py38, lint, typing, pypi-description, manifest, help, docs
+envlist = py37, py38, lint, cov4, typing, pypi-description, manifest, help, docs
 
 
 [testenv]
+# Baseline test environment for both Py 3.7 and 3.8
 setenv =
     VIRTUALENV_NO_DOWNLOAD=1
 extras = dev
@@ -12,30 +13,33 @@ commands =
     python -m pytest --cov=mutatest {posargs}
 
 [testenv:help]
+# Ensure no errors are raised from the help text display
 install_command = pip install --no-compile {opts} {packages}
 setenv =
     PYTHONWARNINGS=d
 commands = mutatest --help
 
+[testenv:cov4]
+# Test with coverage v4 specifically
+commands =
+    pip install 'coverage<5.0'
+    pytest -m coverage
 
 [testenv:lint]
 skip_install = true
 deps = pre-commit
 commands = pre-commit run --all-files --verbose
 
-
 [testenv:typing]
 skip_install = true
 deps = mypy
 commands = mypy --strict mutatest
 
-
 [testenv:docs]
 deps = docs
 changedir = docs
 commands = sphinx-build -W -b html . _build
 
-
 [testenv:pypi-description]
 skip_install = true
 deps =
@@ -47,7 +51,6 @@ commands =
     pip wheel -w {envtmpdir}/build --no-deps .
     twine check {envtmpdir}/build/*
 
-
 [testenv:manifest]
 deps = check-manifest
 skip_install = true