Drop auxiliary requirements files

Move the contents of test-requirements.txt and doc/requirements.txt
into pyproject.toml as project.optional-dependencies (a.k.a.
"extras"). The requirements.txt format is considered pip-specific
and nonstandard.

While we're at it, fine-tune these per test environment.

Change-Id: I477b9685e5d1159086b7a38c9322e07b7c43e2e9

CONTRIBUTING.rst

@@ -32,11 +32,11 @@ testr arguments that are needed to nox. For example, you can run:
 It is also possible to run the tests inside of a virtual environment
 you have created, or it is possible that you have all of the dependencies
 installed locally already. If you'd like to go this route, the requirements
-are listed in pyproject.toml and the requirements for testing are in
-test-requirements.txt. Installing them via pip, for instance, is simply::
+are listed in pyproject.toml and the requirements for testing are in package
+extras defined with project.optional-dependencies entries. Installing them
+via pip, for instance, is simply::
 
-  pip install -r test-requirements.txt
-  pip install -e .
+  pip install -e .[test-unit]
 
 In you go this route, you can interact with the testr command directly.
 Running `testr run` will run the entire test suite. `testr run --parallel`

doc/requirements.txt

@@ -1,6 +0,0 @@
-reno>=2.8.0 # Apache-2.0
-sphinx!=1.6.6,!=1.6.7,!=2.1.0  # BSD
-sphinxcontrib-programoutput  # BSD license
-
-# needed because we use autodoc to document our tests in the dev docs
-fixtures>=0.3.12

noxfile.py

@@ -11,14 +11,13 @@ nox.options.sessions = ["tests-3", "linters"]
 # version using --force-python.
 @nox.session(python="3")
 def linters(session):
-    session.install("hacking>=7,<8")
+    session.install(".[test-linters]")
     session.run("flake8")
 
 
 @nox.session(python="3")
 def docs(session):
-    session.install("-r", "doc/requirements.txt")
-    session.install(".")
+    session.install(".[build-docs]")
     session.run(
         "sphinx-build", "-W",
         "-d", "doc/build/doctrees",
@@ -29,24 +28,21 @@ def docs(session):
 
 @nox.session(python="3")
 def venv(session):
-    session.install("-r", "test-requirements.txt")
-    session.install("-e", ".")
+    session.install("-e", ".[test-unit]")
     session.run(*session.posargs)
 
 
 # This will attempt to run python3 tests by default.
 @nox.session(python=["3"])
 def tests(session):
-    session.install("-r", "test-requirements.txt")
-    session.install("-e", ".")
+    session.install("-e", ".[test-unit]")
     session.run("stestr", "run", *session.posargs)
     session.run("stestr", "slowest")
 
 
 @nox.session(python="3")
 def cover(session):
-    session.install("-r", "test-requirements.txt")
-    session.install("-e", ".")
+    session.install("-e", ".[test-cover]")
     session.env["PYTHON"] = "coverage run --source bindep --parallel-mode"
     session.run("stestr", "run", *session.posargs)
     session.run("stestr", "slowest")

pyproject.toml

@@ -55,6 +55,29 @@ name = "bindep"
 readme = {charset = "UTF-8", content-type = "text/x-rst", file = "README.rst"}
 requires-python = ">=3.7"
 
+[project.optional-dependencies]
+build-docs = [
+    # needed because we use autodoc to document our tests in the dev docs
+    "fixtures>=0.3.12",
+
+    "reno>=2.8.0",  # Apache-2.0
+    "sphinx!=1.6.6,!=1.6.7,!=2.1.0",  # BSD
+    "sphinxcontrib-programoutput",  # BSD license
+]
+test-cover = [
+    "bindep[test-unit]",
+    "coverage>=3.6",
+]
+test-linters = [
+    "hacking>=7,<8"
+]
+test-unit = [
+    "fixtures>=0.3.12",
+    "python-subunit",
+    "stestr>=1",
+    "testtools>=0.9.27",
+]
+
 [project.scripts]
 bindep = "bindep.__main__:main"
 

test-requirements.txt

@@ -1,5 +0,0 @@
-coverage>=3.6
-fixtures>=0.3.12
-python-subunit
-stestr>=1.0.0 # Apache-2.0
-testtools>=0.9.27