ci: use installed pip, upgrade to pinned if necessary (#167)

* ci: use installed pip, upgrade to pinned if necessary

Ref: pytest-dev#6522

* PIP_DISABLE_PIP_VERSION_CHECK=1

.builds/freebsd.yml

@@ -9,6 +9,7 @@ environment:
   PYTEST_ADDOPTS: -vv --showlocals --durations=100
   # XXX: makes testing/test_pdb.py hang (with pexpect).
   PYTEST_REORDER_TESTS: 0
+  PIP_DISABLE_PIP_VERSION_CHECK: 1
 
 tasks:
   - install: |

.github/workflows/main.yml

@@ -111,7 +111,11 @@ jobs:
         key: pre-commit|${{ env.PY_CACHE_KEY }}|${{ hashFiles('.pre-commit-config.yaml') }}
 
     - name: Install tox
-      run: python -m pip install git+https://github.com/blueyed/tox@master
+      env:
+        PIP_DISABLE_PIP_VERSION_CHECK: "1"
+      run: |
+        python -m pip --version
+        python -m pip install git+https://github.com/blueyed/tox@master
 
     - name: Setup tox environment
       run: python -m tox --notest -v --durations -e ${{ matrix.tox_env }}
@@ -145,6 +149,7 @@ jobs:
         python-version: "3.7"
     - name: Install dependencies
       run: |
+        python -m pip --version
         python -m pip install wheel setuptools git+https://github.com/blueyed/tox@master
     - name: Build package
       run: |

.travis.yml

@@ -6,6 +6,7 @@ cache: false
 env:
   global:
     - PYTEST_ADDOPTS="-vv --showlocals --durations=50"
+    - PIP_DISABLE_PIP_VERSION_CHECK=1
 
 # setuptools-scm needs all tags in order to obtain a proper version
 git:
@@ -23,7 +24,7 @@ jobs:
       python: '3.5.1'
       dist: trusty
       before_install:
-        - python -m pip install -U pip
+        - python -m pip install -U pip==19.3.1
 
 before_script:
   - |