95 files changed, 80 insertions, 32 deletions
diff --git a/.github/workflows/unit_tests.yaml b/.github/workflows/unit_tests.yaml
index 764a9cdcf0..2e8f9deef6 100644
--- a/.github/workflows/unit_tests.yaml
+++ b/.github/workflows/unit_tests.yaml
@@ -114,7 +114,7 @@ jobs:
               patchelf cmake bison libbison-dev kcov
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage[toml]
+          pip install --upgrade pip six setuptools pytest codecov coverage[toml]
           # ensure style checks are not skipped in unit tests for python >= 3.6
           # note that true/false (i.e., 1/0) are opposite in conditions in python and bash
           if python -c 'import sys; sys.exit(not sys.version_info >= (3, 6))'; then
@@ -173,7 +173,7 @@ jobs:
           sudo apt-get install -y coreutils kcov csh zsh tcsh fish dash bash
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage[toml]
+          pip install --upgrade pip six setuptools pytest codecov coverage[toml]
     - name: Setup git configuration
       run: |
           # Need this for the git tests to succeed.
@@ -274,7 +274,7 @@ jobs:
               patchelf kcov
     - name: Install Python packages
       run: |
-          pip install --upgrade pip six setuptools codecov coverage[toml] clingo
+          pip install --upgrade pip six setuptools pytest codecov coverage[toml] clingo
     - name: Setup git configuration
       run: |
           # Need this for the git tests to succeed.
@@ -317,7 +317,7 @@ jobs:
     - name: Install Python packages
       run: |
           pip install --upgrade pip six setuptools
-          pip install --upgrade codecov coverage[toml]
+          pip install --upgrade pytest codecov coverage[toml]
     - name: Setup Homebrew packages
       run: |
         brew install dash fish gcc gnupg2 kcov
diff --git a/lib/spack/docs/conf.py b/lib/spack/docs/conf.py
index 2b58223e1d..d0a2bb9e33 100644
--- a/lib/spack/docs/conf.py
+++ b/lib/spack/docs/conf.py
@@ -30,6 +30,7 @@ from sphinx.ext.apidoc import main as sphinx_apidoc
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
 sys.path.insert(0, os.path.abspath('_spack_root/lib/spack/external'))
+sys.path.insert(0, os.path.abspath('_spack_root/lib/spack/external/pytest-fallback'))
 
 if sys.version_info[0] < 3:
     sys.path.insert(
diff --git a/lib/spack/external/_pytest/LICENSE b/lib/spack/external/pytest-fallback/_pytest/LICENSE
index 629df45ac4..629df45ac4 100644
--- a/lib/spack/external/_pytest/LICENSE
+++ b/lib/spack/external/pytest-fallback/_pytest/LICENSE
diff --git a/lib/spack/external/_pytest/__init__.py b/lib/spack/external/pytest-fallback/_pytest/__init__.py
index 6e41f0504e..6e41f0504e 100644
--- a/lib/spack/external/_pytest/__init__.py
+++ b/lib/spack/external/pytest-fallback/_pytest/__init__.py
diff --git a/lib/spack/external/_pytest/_argcomplete.py b/lib/spack/external/pytest-fallback/_pytest/_argcomplete.py
index 965ec79513..965ec79513 100644
--- a/lib/spack/external/_pytest/_argcomplete.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_argcomplete.py
diff --git a/lib/spack/external/_pytest/_code/__init__.py b/lib/spack/external/pytest-fallback/_pytest/_code/__init__.py
index 815c13b42c..815c13b42c 100644
--- a/lib/spack/external/_pytest/_code/__init__.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_code/__init__.py
diff --git a/lib/spack/external/_pytest/_code/_py2traceback.py b/lib/spack/external/pytest-fallback/_pytest/_code/_py2traceback.py
index 5aacf0a428..5aacf0a428 100644
--- a/lib/spack/external/_pytest/_code/_py2traceback.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_code/_py2traceback.py
diff --git a/lib/spack/external/_pytest/_code/code.py b/lib/spack/external/pytest-fallback/_pytest/_code/code.py
index f3b7eedfce..f3b7eedfce 100644
--- a/lib/spack/external/_pytest/_code/code.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_code/code.py
diff --git a/lib/spack/external/_pytest/_code/source.py b/lib/spack/external/pytest-fallback/_pytest/_code/source.py
index fc41712649..fc41712649 100644
--- a/lib/spack/external/_pytest/_code/source.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_code/source.py
diff --git a/lib/spack/external/_pytest/_pluggy.py b/lib/spack/external/pytest-fallback/_pytest/_pluggy.py
index 6cc1d3d54a..6cc1d3d54a 100644
--- a/lib/spack/external/_pytest/_pluggy.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_pluggy.py
diff --git a/lib/spack/external/_pytest/_version.py b/lib/spack/external/pytest-fallback/_pytest/_version.py
index 3edb7da9ad..3edb7da9ad 100644
--- a/lib/spack/external/_pytest/_version.py
+++ b/lib/spack/external/pytest-fallback/_pytest/_version.py
diff --git a/lib/spack/external/_pytest/assertion/__init__.py b/lib/spack/external/pytest-fallback/_pytest/assertion/__init__.py
index b0ef667d56..b0ef667d56 100644
--- a/lib/spack/external/_pytest/assertion/__init__.py
+++ b/lib/spack/external/pytest-fallback/_pytest/assertion/__init__.py
diff --git a/lib/spack/external/_pytest/assertion/rewrite.py b/lib/spack/external/pytest-fallback/_pytest/assertion/rewrite.py
index d48b6648fb..d48b6648fb 100644
--- a/lib/spack/external/_pytest/assertion/rewrite.py
+++ b/lib/spack/external/pytest-fallback/_pytest/assertion/rewrite.py
diff --git a/lib/spack/external/_pytest/assertion/truncate.py b/lib/spack/external/pytest-fallback/_pytest/assertion/truncate.py
index 1e13063569..1e13063569 100644
--- a/lib/spack/external/_pytest/assertion/truncate.py
+++ b/lib/spack/external/pytest-fallback/_pytest/assertion/truncate.py
diff --git a/lib/spack/external/_pytest/assertion/util.py b/lib/spack/external/pytest-fallback/_pytest/assertion/util.py
index c09eff06b0..c09eff06b0 100644
--- a/lib/spack/external/_pytest/assertion/util.py
+++ b/lib/spack/external/pytest-fallback/_pytest/assertion/util.py
diff --git a/lib/spack/external/_pytest/cacheprovider.py b/lib/spack/external/pytest-fallback/_pytest/cacheprovider.py
index c537c14472..c537c14472 100755
--- a/lib/spack/external/_pytest/cacheprovider.py
+++ b/lib/spack/external/pytest-fallback/_pytest/cacheprovider.py
diff --git a/lib/spack/external/_pytest/capture.py b/lib/spack/external/pytest-fallback/_pytest/capture.py
index cb5af6fcb3..cb5af6fcb3 100644
--- a/lib/spack/external/_pytest/capture.py
+++ b/lib/spack/external/pytest-fallback/_pytest/capture.py
diff --git a/lib/spack/external/_pytest/compat.py b/lib/spack/external/pytest-fallback/_pytest/compat.py
index 255f69ce0d..255f69ce0d 100644
--- a/lib/spack/external/_pytest/compat.py
+++ b/lib/spack/external/pytest-fallback/_pytest/compat.py
diff --git a/lib/spack/external/_pytest/config.py b/lib/spack/external/pytest-fallback/_pytest/config.py
index 513478a972..513478a972 100644
--- a/lib/spack/external/_pytest/config.py
+++ b/lib/spack/external/pytest-fallback/_pytest/config.py
diff --git a/lib/spack/external/_pytest/debugging.py b/lib/spack/external/pytest-fallback/_pytest/debugging.py
index aa9c9a3863..aa9c9a3863 100644
--- a/lib/spack/external/_pytest/debugging.py
+++ b/lib/spack/external/pytest-fallback/_pytest/debugging.py
diff --git a/lib/spack/external/_pytest/deprecated.py b/lib/spack/external/pytest-fallback/_pytest/deprecated.py
index 38e9496778..38e9496778 100644
--- a/lib/spack/external/_pytest/deprecated.py
+++ b/lib/spack/external/pytest-fallback/_pytest/deprecated.py
diff --git a/lib/spack/external/_pytest/doctest.py b/lib/spack/external/pytest-fallback/_pytest/doctest.py
index 4c05acddf7..4c05acddf7 100644
--- a/lib/spack/external/_pytest/doctest.py
+++ b/lib/spack/external/pytest-fallback/_pytest/doctest.py
diff --git a/lib/spack/external/_pytest/fixtures.py b/lib/spack/external/pytest-fallback/_pytest/fixtures.py
index 98317a4889..98317a4889 100644
--- a/lib/spack/external/_pytest/fixtures.py
+++ b/lib/spack/external/pytest-fallback/_pytest/fixtures.py
diff --git a/lib/spack/external/_pytest/freeze_support.py b/lib/spack/external/pytest-fallback/_pytest/freeze_support.py
index 97147a8825..97147a8825 100644
--- a/lib/spack/external/_pytest/freeze_support.py
+++ b/lib/spack/external/pytest-fallback/_pytest/freeze_support.py
diff --git a/lib/spack/external/_pytest/helpconfig.py b/lib/spack/external/pytest-fallback/_pytest/helpconfig.py
index e744637f86..e744637f86 100644
--- a/lib/spack/external/_pytest/helpconfig.py
+++ b/lib/spack/external/pytest-fallback/_pytest/helpconfig.py
diff --git a/lib/spack/external/_pytest/hookspec.py b/lib/spack/external/pytest-fallback/_pytest/hookspec.py
index e5c966e58b..e5c966e58b 100644
--- a/lib/spack/external/_pytest/hookspec.py
+++ b/lib/spack/external/pytest-fallback/_pytest/hookspec.py
diff --git a/lib/spack/external/_pytest/junitxml.py b/lib/spack/external/pytest-fallback/_pytest/junitxml.py
index 7fb40dc354..7fb40dc354 100644
--- a/lib/spack/external/_pytest/junitxml.py
+++ b/lib/spack/external/pytest-fallback/_pytest/junitxml.py
diff --git a/lib/spack/external/_pytest/main.py b/lib/spack/external/pytest-fallback/_pytest/main.py
index 98aa28eb34..98aa28eb34 100644
--- a/lib/spack/external/_pytest/main.py
+++ b/lib/spack/external/pytest-fallback/_pytest/main.py
diff --git a/lib/spack/external/_pytest/mark.py b/lib/spack/external/pytest-fallback/_pytest/mark.py
index 454722ca2c..454722ca2c 100644
--- a/lib/spack/external/_pytest/mark.py
+++ b/lib/spack/external/pytest-fallback/_pytest/mark.py
diff --git a/lib/spack/external/_pytest/monkeypatch.py b/lib/spack/external/pytest-fallback/_pytest/monkeypatch.py
index 39ac770135..39ac770135 100644
--- a/lib/spack/external/_pytest/monkeypatch.py
+++ b/lib/spack/external/pytest-fallback/_pytest/monkeypatch.py
diff --git a/lib/spack/external/_pytest/nodes.py b/lib/spack/external/pytest-fallback/_pytest/nodes.py
index ad3af2ce67..ad3af2ce67 100644
--- a/lib/spack/external/_pytest/nodes.py
+++ b/lib/spack/external/pytest-fallback/_pytest/nodes.py
diff --git a/lib/spack/external/_pytest/nose.py b/lib/spack/external/pytest-fallback/_pytest/nose.py
index d246c5603d..d246c5603d 100644
--- a/lib/spack/external/_pytest/nose.py
+++ b/lib/spack/external/pytest-fallback/_pytest/nose.py
diff --git a/lib/spack/external/_pytest/outcomes.py b/lib/spack/external/pytest-fallback/_pytest/outcomes.py
index ff5ef756d9..ff5ef756d9 100644
--- a/lib/spack/external/_pytest/outcomes.py
+++ b/lib/spack/external/pytest-fallback/_pytest/outcomes.py
diff --git a/lib/spack/external/_pytest/pastebin.py b/lib/spack/external/pytest-fallback/_pytest/pastebin.py
index 9d689819f0..9d689819f0 100644
--- a/lib/spack/external/_pytest/pastebin.py
+++ b/lib/spack/external/pytest-fallback/_pytest/pastebin.py
diff --git a/lib/spack/external/_pytest/pytester.py b/lib/spack/external/pytest-fallback/_pytest/pytester.py
index 82aa00e0d2..82aa00e0d2 100644
--- a/lib/spack/external/_pytest/pytester.py
+++ b/lib/spack/external/pytest-fallback/_pytest/pytester.py
diff --git a/lib/spack/external/_pytest/python.py b/lib/spack/external/pytest-fallback/_pytest/python.py
index 41fd2bdb7f..41fd2bdb7f 100644
--- a/lib/spack/external/_pytest/python.py
+++ b/lib/spack/external/pytest-fallback/_pytest/python.py
diff --git a/lib/spack/external/_pytest/python_api.py b/lib/spack/external/pytest-fallback/_pytest/python_api.py
index a931b4d2c7..a931b4d2c7 100644
--- a/lib/spack/external/_pytest/python_api.py
+++ b/lib/spack/external/pytest-fallback/_pytest/python_api.py
diff --git a/lib/spack/external/_pytest/recwarn.py b/lib/spack/external/pytest-fallback/_pytest/recwarn.py
index c9fa872c07..c9fa872c07 100644
--- a/lib/spack/external/_pytest/recwarn.py
+++ b/lib/spack/external/pytest-fallback/_pytest/recwarn.py
diff --git a/lib/spack/external/_pytest/resultlog.py b/lib/spack/external/pytest-fallback/_pytest/resultlog.py
index 9f9c2d1f65..9f9c2d1f65 100644
--- a/lib/spack/external/_pytest/resultlog.py
+++ b/lib/spack/external/pytest-fallback/_pytest/resultlog.py
diff --git a/lib/spack/external/_pytest/runner.py b/lib/spack/external/pytest-fallback/_pytest/runner.py
index b643fa3c91..b643fa3c91 100644
--- a/lib/spack/external/_pytest/runner.py
+++ b/lib/spack/external/pytest-fallback/_pytest/runner.py
diff --git a/lib/spack/external/_pytest/setuponly.py b/lib/spack/external/pytest-fallback/_pytest/setuponly.py
index 15e195ad5a..15e195ad5a 100644
--- a/lib/spack/external/_pytest/setuponly.py
+++ b/lib/spack/external/pytest-fallback/_pytest/setuponly.py
diff --git a/lib/spack/external/_pytest/setupplan.py b/lib/spack/external/pytest-fallback/_pytest/setupplan.py
index e11bd40698..e11bd40698 100644
--- a/lib/spack/external/_pytest/setupplan.py
+++ b/lib/spack/external/pytest-fallback/_pytest/setupplan.py
diff --git a/lib/spack/external/_pytest/skipping.py b/lib/spack/external/pytest-fallback/_pytest/skipping.py
index b92800d10b..b92800d10b 100644
--- a/lib/spack/external/_pytest/skipping.py
+++ b/lib/spack/external/pytest-fallback/_pytest/skipping.py
diff --git a/lib/spack/external/_pytest/terminal.py b/lib/spack/external/pytest-fallback/_pytest/terminal.py
index 9da94d0c91..9da94d0c91 100644
--- a/lib/spack/external/_pytest/terminal.py
+++ b/lib/spack/external/pytest-fallback/_pytest/terminal.py
diff --git a/lib/spack/external/_pytest/tmpdir.py b/lib/spack/external/pytest-fallback/_pytest/tmpdir.py
index da1b032237..da1b032237 100644
--- a/lib/spack/external/_pytest/tmpdir.py
+++ b/lib/spack/external/pytest-fallback/_pytest/tmpdir.py
diff --git a/lib/spack/external/_pytest/unittest.py b/lib/spack/external/pytest-fallback/_pytest/unittest.py
index 52c9813e8b..52c9813e8b 100644
--- a/lib/spack/external/_pytest/unittest.py
+++ b/lib/spack/external/pytest-fallback/_pytest/unittest.py
diff --git a/lib/spack/external/_pytest/vendored_packages/README.md b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/README.md
index b5fe6febb0..b5fe6febb0 100644
--- a/lib/spack/external/_pytest/vendored_packages/README.md
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/README.md
diff --git a/lib/spack/external/_pytest/vendored_packages/__init__.py b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/__init__.py
index e69de29bb2..e69de29bb2 100644
--- a/lib/spack/external/_pytest/vendored_packages/__init__.py
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/__init__.py
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/DESCRIPTION.rst b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/DESCRIPTION.rst
index da0e7a6ed7..da0e7a6ed7 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/DESCRIPTION.rst
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/DESCRIPTION.rst
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/INSTALLER b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/INSTALLER
index a1b589e38a..a1b589e38a 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/INSTALLER
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/INSTALLER
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/LICENSE.txt b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/LICENSE.txt
index 121017d086..121017d086 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/LICENSE.txt
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/LICENSE.txt
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/METADATA b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/METADATA
index bd88517c94..bd88517c94 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/METADATA
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/METADATA
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/RECORD b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/RECORD
index 3003a3bf2b..3003a3bf2b 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/RECORD
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/RECORD
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/WHEEL b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/WHEEL
index 8b6dd1b5a8..8b6dd1b5a8 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/WHEEL
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/WHEEL
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/metadata.json b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/metadata.json
index cde22aff02..cde22aff02 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/metadata.json
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/metadata.json
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/top_level.txt b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/top_level.txt
index 11bdb5c1f5..11bdb5c1f5 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy-0.4.0.dist-info/top_level.txt
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy-0.4.0.dist-info/top_level.txt
diff --git a/lib/spack/external/_pytest/vendored_packages/pluggy.py b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy.py
index 6f26552d73..6f26552d73 100644
--- a/lib/spack/external/_pytest/vendored_packages/pluggy.py
+++ b/lib/spack/external/pytest-fallback/_pytest/vendored_packages/pluggy.py
diff --git a/lib/spack/external/_pytest/warnings.py b/lib/spack/external/pytest-fallback/_pytest/warnings.py
index 926b1f5811..926b1f5811 100644
--- a/lib/spack/external/_pytest/warnings.py
+++ b/lib/spack/external/pytest-fallback/_pytest/warnings.py
diff --git a/lib/spack/external/py/__init__.py b/lib/spack/external/pytest-fallback/py/__init__.py
index 85af650f5c..85af650f5c 100644
--- a/lib/spack/external/py/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/__init__.py
diff --git a/lib/spack/external/py/__metainfo.py b/lib/spack/external/pytest-fallback/py/__metainfo.py
index 12581eb7af..12581eb7af 100644
--- a/lib/spack/external/py/__metainfo.py
+++ b/lib/spack/external/pytest-fallback/py/__metainfo.py
diff --git a/lib/spack/external/py/_apipkg.py b/lib/spack/external/pytest-fallback/py/_apipkg.py
index a73b8f6d0b..a73b8f6d0b 100644
--- a/lib/spack/external/py/_apipkg.py
+++ b/lib/spack/external/pytest-fallback/py/_apipkg.py
diff --git a/lib/spack/external/py/_builtin.py b/lib/spack/external/pytest-fallback/py/_builtin.py
index 52ee9d79ca..52ee9d79ca 100644
--- a/lib/spack/external/py/_builtin.py
+++ b/lib/spack/external/pytest-fallback/py/_builtin.py
diff --git a/lib/spack/external/py/_code/__init__.py b/lib/spack/external/pytest-fallback/py/_code/__init__.py
index f15acf8513..f15acf8513 100644
--- a/lib/spack/external/py/_code/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/_code/__init__.py
diff --git a/lib/spack/external/py/_code/_assertionnew.py b/lib/spack/external/pytest-fallback/py/_code/_assertionnew.py
index afb1b31ff0..afb1b31ff0 100644
--- a/lib/spack/external/py/_code/_assertionnew.py
+++ b/lib/spack/external/pytest-fallback/py/_code/_assertionnew.py
diff --git a/lib/spack/external/py/_code/_assertionold.py b/lib/spack/external/pytest-fallback/py/_code/_assertionold.py
index 4e81fb3ef6..4e81fb3ef6 100644
--- a/lib/spack/external/py/_code/_assertionold.py
+++ b/lib/spack/external/pytest-fallback/py/_code/_assertionold.py
diff --git a/lib/spack/external/py/_code/_py2traceback.py b/lib/spack/external/pytest-fallback/py/_code/_py2traceback.py
index d65e27cb73..d65e27cb73 100644
--- a/lib/spack/external/py/_code/_py2traceback.py
+++ b/lib/spack/external/pytest-fallback/py/_code/_py2traceback.py
diff --git a/lib/spack/external/py/_code/assertion.py b/lib/spack/external/pytest-fallback/py/_code/assertion.py
index 4ce80c75b1..4ce80c75b1 100644
--- a/lib/spack/external/py/_code/assertion.py
+++ b/lib/spack/external/pytest-fallback/py/_code/assertion.py
diff --git a/lib/spack/external/py/_code/code.py b/lib/spack/external/pytest-fallback/py/_code/code.py
index 20fd965c97..20fd965c97 100644
--- a/lib/spack/external/py/_code/code.py
+++ b/lib/spack/external/pytest-fallback/py/_code/code.py
diff --git a/lib/spack/external/py/_code/source.py b/lib/spack/external/pytest-fallback/py/_code/source.py
index c8b668b2fb..c8b668b2fb 100644
--- a/lib/spack/external/py/_code/source.py
+++ b/lib/spack/external/pytest-fallback/py/_code/source.py
diff --git a/lib/spack/external/py/_error.py b/lib/spack/external/pytest-fallback/py/_error.py
index 8ca339beba..8ca339beba 100644
--- a/lib/spack/external/py/_error.py
+++ b/lib/spack/external/pytest-fallback/py/_error.py
diff --git a/lib/spack/external/py/_iniconfig.py b/lib/spack/external/pytest-fallback/py/_iniconfig.py
index 92b50bd853..92b50bd853 100644
--- a/lib/spack/external/py/_iniconfig.py
+++ b/lib/spack/external/pytest-fallback/py/_iniconfig.py
diff --git a/lib/spack/external/py/_io/__init__.py b/lib/spack/external/pytest-fallback/py/_io/__init__.py
index 835f01f3ab..835f01f3ab 100644
--- a/lib/spack/external/py/_io/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/_io/__init__.py
diff --git a/lib/spack/external/py/_io/capture.py b/lib/spack/external/pytest-fallback/py/_io/capture.py
index bc157ed978..bc157ed978 100644
--- a/lib/spack/external/py/_io/capture.py
+++ b/lib/spack/external/pytest-fallback/py/_io/capture.py
diff --git a/lib/spack/external/py/_io/saferepr.py b/lib/spack/external/pytest-fallback/py/_io/saferepr.py
index 8518290efd..8518290efd 100644
--- a/lib/spack/external/py/_io/saferepr.py
+++ b/lib/spack/external/pytest-fallback/py/_io/saferepr.py
diff --git a/lib/spack/external/py/_io/terminalwriter.py b/lib/spack/external/pytest-fallback/py/_io/terminalwriter.py
index 390e8ca7b9..390e8ca7b9 100644
--- a/lib/spack/external/py/_io/terminalwriter.py
+++ b/lib/spack/external/pytest-fallback/py/_io/terminalwriter.py
diff --git a/lib/spack/external/py/_log/__init__.py b/lib/spack/external/pytest-fallback/py/_log/__init__.py
index fad62e960d..fad62e960d 100644
--- a/lib/spack/external/py/_log/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/_log/__init__.py
diff --git a/lib/spack/external/py/_log/log.py b/lib/spack/external/pytest-fallback/py/_log/log.py
index ce47e8c754..ce47e8c754 100644
--- a/lib/spack/external/py/_log/log.py
+++ b/lib/spack/external/pytest-fallback/py/_log/log.py
diff --git a/lib/spack/external/py/_log/warning.py b/lib/spack/external/pytest-fallback/py/_log/warning.py
index 722e31e910..722e31e910 100644
--- a/lib/spack/external/py/_log/warning.py
+++ b/lib/spack/external/pytest-fallback/py/_log/warning.py
diff --git a/lib/spack/external/py/_path/__init__.py b/lib/spack/external/pytest-fallback/py/_path/__init__.py
index 51f3246f80..51f3246f80 100644
--- a/lib/spack/external/py/_path/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/_path/__init__.py
diff --git a/lib/spack/external/py/_path/cacheutil.py b/lib/spack/external/pytest-fallback/py/_path/cacheutil.py
index 9922504750..9922504750 100644
--- a/lib/spack/external/py/_path/cacheutil.py
+++ b/lib/spack/external/pytest-fallback/py/_path/cacheutil.py
diff --git a/lib/spack/external/py/_path/common.py b/lib/spack/external/pytest-fallback/py/_path/common.py
index 5512e51efe..5512e51efe 100644
--- a/lib/spack/external/py/_path/common.py
+++ b/lib/spack/external/pytest-fallback/py/_path/common.py
diff --git a/lib/spack/external/py/_path/local.py b/lib/spack/external/pytest-fallback/py/_path/local.py
index d2f16b993e..d2f16b993e 100644
--- a/lib/spack/external/py/_path/local.py
+++ b/lib/spack/external/pytest-fallback/py/_path/local.py
diff --git a/lib/spack/external/py/_path/svnurl.py b/lib/spack/external/pytest-fallback/py/_path/svnurl.py
index 6589a71d09..6589a71d09 100644
--- a/lib/spack/external/py/_path/svnurl.py
+++ b/lib/spack/external/pytest-fallback/py/_path/svnurl.py
diff --git a/lib/spack/external/py/_path/svnwc.py b/lib/spack/external/pytest-fallback/py/_path/svnwc.py
index 992223c04a..992223c04a 100644
--- a/lib/spack/external/py/_path/svnwc.py
+++ b/lib/spack/external/pytest-fallback/py/_path/svnwc.py
diff --git a/lib/spack/external/py/_process/__init__.py b/lib/spack/external/pytest-fallback/py/_process/__init__.py
index 86c714ad1a..86c714ad1a 100644
--- a/lib/spack/external/py/_process/__init__.py
+++ b/lib/spack/external/pytest-fallback/py/_process/__init__.py
diff --git a/lib/spack/external/py/_process/cmdexec.py b/lib/spack/external/pytest-fallback/py/_process/cmdexec.py
index f83a249402..f83a249402 100644
--- a/lib/spack/external/py/_process/cmdexec.py
+++ b/lib/spack/external/pytest-fallback/py/_process/cmdexec.py
diff --git a/lib/spack/external/py/_process/forkedfunc.py b/lib/spack/external/pytest-fallback/py/_process/forkedfunc.py
index 1c28530688..1c28530688 100644
--- a/lib/spack/external/py/_process/forkedfunc.py
+++ b/lib/spack/external/pytest-fallback/py/_process/forkedfunc.py
diff --git a/lib/spack/external/py/_process/killproc.py b/lib/spack/external/pytest-fallback/py/_process/killproc.py
index 18e8310b5f..18e8310b5f 100644
--- a/lib/spack/external/py/_process/killproc.py
+++ b/lib/spack/external/pytest-fallback/py/_process/killproc.py
diff --git a/lib/spack/external/py/_std.py b/lib/spack/external/pytest-fallback/py/_std.py
index 97a9853323..97a9853323 100644
--- a/lib/spack/external/py/_std.py
+++ b/lib/spack/external/pytest-fallback/py/_std.py
diff --git a/lib/spack/external/py/_xmlgen.py b/lib/spack/external/pytest-fallback/py/_xmlgen.py
index 1c83545884..1c83545884 100644
--- a/lib/spack/external/py/_xmlgen.py
+++ b/lib/spack/external/pytest-fallback/py/_xmlgen.py
diff --git a/lib/spack/external/py/test.py b/lib/spack/external/pytest-fallback/py/test.py
index aa5beb1789..aa5beb1789 100644
--- a/lib/spack/external/py/test.py
+++ b/lib/spack/external/pytest-fallback/py/test.py
diff --git a/lib/spack/external/pytest.py b/lib/spack/external/pytest-fallback/pytest.py
index 6e124db418..6e124db418 100644
--- a/lib/spack/external/pytest.py
+++ b/lib/spack/external/pytest-fallback/pytest.py
diff --git a/lib/spack/spack/cmd/unit_test.py b/lib/spack/spack/cmd/unit_test.py
index ce4e2cbdbb..0f117f2d7a 100644
--- a/lib/spack/spack/cmd/unit_test.py
+++ b/lib/spack/spack/cmd/unit_test.py
@@ -7,14 +7,19 @@ from __future__ import division, print_function
 
 import argparse
 import collections
+import os.path
 import re
 import sys
 
-import pytest
+try:
+    import pytest
+except ImportError:
+    pytest = None   # type: ignore
+
 from six import StringIO
 
+import llnl.util.filesystem
 import llnl.util.tty.color as color
-from llnl.util.filesystem import working_dir
 from llnl.util.tty.colify import colify
 
 import spack.paths
@@ -67,7 +72,25 @@ def setup_parser(subparser):
 
 def do_list(args, extra_args):
     """Print a lists of tests than what pytest offers."""
-    # Run test collection and get the tree out.
+    def colorize(c, prefix):
+        if isinstance(prefix, tuple):
+            return "::".join(
+                color.colorize("@%s{%s}" % (c, p))
+                for p in prefix if p != "()"
+            )
+        return color.colorize("@%s{%s}" % (c, prefix))
+
+    # To list the files we just need to inspect the filesystem,
+    # which doesn't need to wait for pytest collection and doesn't
+    # require parsing pytest output
+    files = llnl.util.filesystem.find(
+        root=spack.paths.test_path, files='*.py', recursive=True
+    )
+    files = [
+        os.path.relpath(f, start=spack.paths.spack_root)
+        for f in files if not f.endswith(('conftest.py', '__init__.py'))
+    ]
+
     old_output = sys.stdout
     try:
         sys.stdout = output = StringIO()
@@ -76,12 +99,13 @@ def do_list(args, extra_args):
         sys.stdout = old_output
 
     lines = output.getvalue().split('\n')
-    tests = collections.defaultdict(lambda: set())
-    prefix = []
+    tests = collections.defaultdict(set)
 
     # collect tests into sections
+    node_regexp = re.compile(r"(\s*)<([^ ]*) ['\"]?([^']*)['\"]?>")
+    key_parts, name_parts = [], []
     for line in lines:
-        match = re.match(r"(\s*)<([^ ]*) '([^']*)'", line)
+        match = node_regexp.match(line)
         if not match:
             continue
         indent, nodetype, name = match.groups()
@@ -90,25 +114,31 @@ def do_list(args, extra_args):
         if "[" in name:
             name = name[:name.index("[")]
 
-        depth = len(indent) // 2
-
-        if nodetype.endswith("Function"):
-            key = tuple(prefix)
-            tests[key].add(name)
-        else:
-            prefix = prefix[:depth]
-            prefix.append(name)
-
-    def colorize(c, prefix):
-        if isinstance(prefix, tuple):
-            return "::".join(
-                color.colorize("@%s{%s}" % (c, p))
-                for p in prefix if p != "()"
-            )
-        return color.colorize("@%s{%s}" % (c, prefix))
+        len_indent = len(indent)
+        if os.path.isabs(name):
+            name = os.path.relpath(name, start=spack.paths.spack_root)
+
+        item = (len_indent, name, nodetype)
+
+        # Reduce the parts to the scopes that are of interest
+        name_parts = [x for x in name_parts if x[0] < len_indent]
+        key_parts = [x for x in key_parts if x[0] < len_indent]
+
+        # From version 3.X to version 6.X the output format
+        # changed a lot in pytest, and probably will change
+        # in the future - so this manipulation might be fragile
+        if nodetype.lower() == 'function':
+            name_parts.append(item)
+            key_end = os.path.join(*[x[1] for x in key_parts])
+            key = next(f for f in files if f.endswith(key_end))
+            tests[key].add(tuple(x[1] for x in name_parts))
+        elif nodetype.lower() == 'class':
+            name_parts.append(item)
+        elif nodetype.lower() in ('package', 'module'):
+            key_parts.append(item)
 
     if args.list == "list":
-        files = set(prefix[0] for prefix in tests)
+        files = set(tests.keys())
         color_files = [colorize("B", file) for file in sorted(files)]
         colify(color_files)
 
@@ -144,6 +174,14 @@ def add_back_pytest_args(args, unknown_args):
 
 
 def unit_test(parser, args, unknown_args):
+    global pytest
+    if pytest is None:
+        vendored_pytest_dir = os.path.join(
+            spack.paths.external_path, 'pytest-fallback'
+        )
+        sys.path.append(vendored_pytest_dir)
+        import pytest
+
     if args.pytest_help:
         # make the pytest.main help output more accurate
         sys.argv[0] = 'spack unit-test'
@@ -161,7 +199,7 @@ def unit_test(parser, args, unknown_args):
         pytest_root = spack.extensions.path_for_extension(target, *extensions)
 
     # pytest.ini lives in the root of the spack repository.
-    with working_dir(pytest_root):
+    with llnl.util.filesystem.working_dir(pytest_root):
         if args.list:
             do_list(args, pytest_args)
             return
diff --git a/lib/spack/spack/test/cmd/unit_test.py b/lib/spack/spack/test/cmd/unit_test.py
index 1a273ff244..9811bdbfbd 100644
--- a/lib/spack/spack/test/cmd/unit_test.py
+++ b/lib/spack/spack/test/cmd/unit_test.py
@@ -22,7 +22,10 @@ def test_list_with_pytest_arg():
 
 
 def test_list_with_keywords():
-    output = spack_test('--list', '-k', 'cmd/unit_test.py')
+    # Here we removed querying with a "/" to separate directories
+    # since the behavior is inconsistent across different pytest
+    # versions, see https://stackoverflow.com/a/48814787/771663
+    output = spack_test('--list', '-k', 'unit_test.py')
     assert output.strip() == cmd_test_py
 
 
diff --git a/lib/spack/spack/test/conftest.py b/lib/spack/spack/test/conftest.py
index 9a6dc0b13b..d502cf1db1 100644
--- a/lib/spack/spack/test/conftest.py
+++ b/lib/spack/spack/test/conftest.py
@@ -430,8 +430,14 @@ def _skip_if_missing_executables(request):
     """Permits to mark tests with 'require_executables' and skip the
     tests if the executables passed as arguments are not found.
     """
-    if request.node.get_marker('requires_executables'):
-        required_execs = request.node.get_marker('requires_executables').args
+    if hasattr(request.node, 'get_marker'):
+        # TODO: Remove the deprecated API as soon as we drop support for Python 2.6
+        marker = request.node.get_marker('requires_executables')
+    else:
+        marker = request.node.get_closest_marker('requires_executables')
+
+    if marker:
+        required_execs = marker.args
         missing_execs = [
             x for x in required_execs if spack.util.executable.which(x) is None
         ]
@@ -1453,7 +1459,7 @@ def invalid_spec(request):
     return request.param
 
 
-@pytest.fixture("module")
+@pytest.fixture(scope='module')
 def mock_test_repo(tmpdir_factory):
     """Create an empty repository."""
     repo_namespace = 'mock_test_repo'