Fix Cygwin installation on CI for pip

.github/workflows/alpine-test.yml

@@ -47,13 +47,12 @@ jobs:
         # and cause subsequent tests to fail
         cat test/fixtures/.gitconfig >> ~/.gitconfig
 
-    - name: Set up virtualenv
+    - name: Set up virtual environment
       run: |
         python -m venv .venv
 
     - name: Update PyPA packages
       run: |
-        # Get the latest pip, wheel, and prior to Python 3.12, setuptools.
         . .venv/bin/activate
         python -m pip install -U pip 'setuptools; python_version<"3.12"' wheel
 

.github/workflows/cygwin-test.yml

@@ -7,8 +7,6 @@ permissions:
 
 jobs:
   test:
-    runs-on: windows-latest
-
     strategy:
       matrix:
         selection: [fast, perf]
@@ -20,6 +18,8 @@ jobs:
 
       fail-fast: false
 
+    runs-on: windows-latest
+
     env:
       CHERE_INVOKING: "1"
       CYGWIN_NOWINPATH: "1"
@@ -32,7 +32,7 @@ jobs:
     - name: Force LF line endings
       run: |
         git config --global core.autocrlf false  # Affects the non-Cygwin git.
-      shell: bash  # Use Git Bash instead of Cygwin Bash for this step.
+      shell: pwsh  # Do this outside Cygwin, to affect actions/checkout.
 
     - uses: actions/checkout@v4
       with:
@@ -41,7 +41,7 @@ jobs:
     - name: Install Cygwin
       uses: cygwin/cygwin-install-action@v5
       with:
-        packages: python39 python39-pip python39-virtualenv git wget
+        packages: git python39 python-pip-wheel python-setuptools-wheel python-wheel-wheel
         add-to-path: false  # No need to change $PATH outside the Cygwin environment.
 
     - name: Arrange for verbose output
@@ -67,18 +67,13 @@ jobs:
         # and cause subsequent tests to fail
         cat test/fixtures/.gitconfig >> ~/.gitconfig
 
-    - name: Set up virtualenv
+    - name: Set up virtual environment
       run: |
-        python3.9 -m venv --without-pip .venv
+        python3.9 -m venv .venv
         echo 'BASH_ENV=.venv/bin/activate' >>"$GITHUB_ENV"
 
-    - name: Bootstrap pip in virtualenv
-      run: |
-        wget -qO- https://bootstrap.pypa.io/get-pip.py | python
-
     - name: Update PyPA packages
       run: |
-        # Get the latest pip, wheel, and prior to Python 3.12, setuptools.
         python -m pip install -U pip 'setuptools; python_version<"3.12"' wheel
 
     - name: Install project and test dependencies

.github/workflows/pythonpackage.yml

@@ -71,7 +71,6 @@ jobs:
 
     - name: Update PyPA packages
       run: |
-        # Get the latest pip, wheel, and prior to Python 3.12, setuptools.
         python -m pip install -U pip 'setuptools; python_version<"3.12"' wheel
 
     - name: Install project and test dependencies

test/test_installation.py

@@ -4,19 +4,11 @@
 import ast
 import os
 import subprocess
-import sys
-
-import pytest
 
 from test.lib import TestBase, VirtualEnvironment, with_rw_directory
 
 
 class TestInstallation(TestBase):
-    @pytest.mark.xfail(
-        sys.platform == "cygwin" and "CI" in os.environ,
-        reason="Trouble with pip on Cygwin CI, see issue #2004",
-        raises=subprocess.CalledProcessError,
-    )
     @with_rw_directory
     def test_installation(self, rw_dir):
         venv = self._set_up_venv(rw_dir)