GH Action: Add missing tox environments

Use the recently added GNUPG env variable to hide gpg.

Author: Jussi Kukkonen

.github/workflows/ci.yml

@@ -13,7 +13,19 @@ jobs:
         os: [ubuntu-latest, macos-latest]
         toxenv: [py]
 
-        # TODO add special cases: purepy27, purepy38, py27-no-gpg, py38-no-gpg
+        include:
+          - python-version: 2.7
+            os: ubuntu-latest
+            toxenv: purepy27
+          - python-version: 2.7
+            os: ubuntu-latest
+            toxenv: py27-no-gpg
+          - python-version: 3.8
+            os: ubuntu-latest
+            toxenv: purepy38
+          - python-version: 3.8
+            os: ubuntu-latest
+            toxenv: py38-no-gpg
 
     runs-on: ${{ matrix.os }}
 

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = py27, py36, py37, py38, py39 purepy27, purepy38
+envlist = py27, py36, py37, py38, py39, purepy27, purepy38, py27-no-gpg, py38-no-gpg
 skipsdist = True
 
 [testenv]
@@ -34,12 +34,14 @@ deps =
 commands =
     python -m tests.check_public_interfaces
 
-# Below test envs require manual removal of gpg on the host system (see
-# .travis.yml) and are excluded from the default tox run
 [testenv:py27-no-gpg]
+setenv =
+    GNUPG = nonexisting-gpg-for-testing
 commands =
     python -m tests.check_public_interfaces_gpg
 
 [testenv:py38-no-gpg]
+setenv =
+    GNUPG = nonexisting-gpg-for-testing
 commands =
     python -m tests.check_public_interfaces_gpg