coverage: move config from .coveragerc to pyproject.toml

Getting rid of another top-level file.

`coverage.py` has supported `pyproject.toml` since version 5.0, and
all versions of coverage so far work with python 2.7. We just need to
ensure that a version of coverage with the `toml` extra is installed
in the test environment.

I tested this with `coverage run`, `coverage report`, and `coverage html`.

Author: tgamblin

.coveragerc

@@ -137,7 +137,7 @@ jobs:
           sudo apt-get -y install zlib1g-dev libdw-dev libiberty-dev
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage
+          pip install --upgrade pip six setuptools codecov coverage[toml]
     - name: Setup git configuration
       run: |
           # Need this for the git tests to succeed.
@@ -205,7 +205,7 @@ jobs:
           sudo apt-get -y install zlib1g-dev libdw-dev libiberty-dev
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage
+          pip install --upgrade pip six setuptools codecov coverage[toml]
     - name: Setup git configuration
       run: |
           # Need this for the git tests to succeed.
@@ -326,7 +326,7 @@ jobs:
           make -C ${KCOV_ROOT}/build && sudo  make -C ${KCOV_ROOT}/build install
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage clingo
+          pip install --upgrade pip six setuptools codecov coverage[toml] clingo
     - name: Setup git configuration
       run: |
           # Need this for the git tests to succeed.
@@ -369,7 +369,7 @@ jobs:
     - name: Install Python packages
       run: |
           pip install --upgrade pip six setuptools
-          pip install --upgrade codecov coverage
+          pip install --upgrade codecov coverage[toml]
           pip install --upgrade flake8 isort>=4.3.5 mypy>=0.900
     - name: Setup Homebrew packages
       run: |

.github/workflows/unit_tests.yaml

@@ -26,33 +26,69 @@ namespace_packages = true
 ignore_errors = true
 ignore_missing_imports = true
 
-[[tool.mypy.overrides]]
-module = 'spack.*'
-ignore_errors = false
-ignore_missing_imports = false
-
-[[tool.mypy.overrides]]
-module = 'packages.*'
-ignore_errors = false
-ignore_missing_imports = false
-
-[[tool.mypy.overrides]]
-module = 'llnl.*'
-ignore_errors = false
-ignore_missing_imports = false
-
-[[tool.mypy.overrides]]
-module = 'spack.test.packages'
-ignore_errors = true
+  [[tool.mypy.overrides]]
+  module = 'spack.*'
+  ignore_errors = false
+  ignore_missing_imports = false
+
+  [[tool.mypy.overrides]]
+  module = 'packages.*'
+  ignore_errors = false
+  ignore_missing_imports = false
+
+  [[tool.mypy.overrides]]
+  module = 'llnl.*'
+  ignore_errors = false
+  ignore_missing_imports = false
+
+  [[tool.mypy.overrides]]
+  module = 'spack.test.packages'
+  ignore_errors = true
 
-# ignore errors in fake import path for packages
-[[tool.mypy.overrides]]
-module = 'spack.pkg.*'
+  # ignore errors in fake import path for packages
+  [[tool.mypy.overrides]]
+  module = 'spack.pkg.*'
+  ignore_errors = true
+  ignore_missing_imports = true
+
+  # jinja has syntax in it that requires python3 and causes a parse error
+  # skip importing it
+  [[tool.mypy.overrides]]
+  module = 'jinja2'
+  follow_imports = 'skip'
+
+[tool.coverage.run]
+parallel = true
+concurrency = ["multiprocessing"]
+branch = true
+source = ["bin", "lib"]
+omit = [
+    'lib/spack/spack/test/*',
+    'lib/spack/docs/*',
+    'lib/spack/external/*',
+    'share/spack/qa/*',
+]
+
+[tool.coverage.report]
+# Regexes for lines to exclude from consideration
+exclude_lines = [
+    # Have to re-enable the standard pragma
+    'pragma: no cover',
+
+    # Don't complain about missing debug-only code:
+    'def __repr__',
+    'if self\.debug',
+
+    # Don't complain if tests don't hit defensive assertion code:
+    'raise AssertionError',
+    'raise NotImplementedError',
+
+    # Don't complain if non-runnable code isn't run:
+    'if 0:',
+    'if False:',
+    'if __name__ == .__main__.:',
+]
 ignore_errors = true
-ignore_missing_imports = true
 
-# jinja has syntax in it that requires python3 and causes a parse error
-# skip importing it
-[[tool.mypy.overrides]]
-module = 'jinja2'
-follow_imports = 'skip'
+[tool.coverage.html]
+directory = "htmlcov"