Fix warnings on eliding label for 5.12, test more qt versions (#19)

* more tests and eliding fix

* update tests

* tox env override

* remove ubuntu 16

* still trying to fix tests

* add backends

.github/workflows/test_and_deploy.yml

@@ -60,20 +60,26 @@ jobs:
           - python-version: 3.8
             platform: ubuntu-18.04
             backend: pyside2
-          - python-version: 3.6
-            platform: ubuntu-16.04
-            backend: pyqt5
           - python-version: 3.6
             platform: windows-2016
             backend: pyqt5
 
           # legacy Qt
+          - python-version: 3.7
+            platform: ubuntu-latest
+            backend: pyside511
           - python-version: 3.7
             platform: ubuntu-latest
             backend: pyqt511
           - python-version: 3.7
             platform: ubuntu-latest
-            backend: pyside511
+            backend: pyqt512
+          - python-version: 3.7
+            platform: ubuntu-latest
+            backend: pyqt513
+          - python-version: 3.7
+            platform: ubuntu-latest
+            backend: pyqt514
 
     steps:
       - uses: actions/checkout@v2
@@ -83,12 +89,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
-      - name: Install Linux libraries
-        if: runner.os == 'Linux'
-        run: |
-          sudo apt-get install -y libdbus-1-3 libxkbcommon-x11-0 libxcb-icccm4 \
-            libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 \
-            libxcb-xinerama0 libxcb-xfixes0
+      - uses: tlambert03/setup-qt-libs@v1
 
       - name: Linux opengl
         if: runner.os == 'Linux' && ( matrix.backend == 'pyside6' || matrix.backend == 'pyqt6' )
@@ -100,7 +101,9 @@ jobs:
           pip install setuptools tox tox-gh-actions
 
       - name: Test with tox
-        run: tox
+        uses: GabrielBB/xvfb-action@v1
+        with:
+          run: tox
         env:
           PLATFORM: ${{ matrix.platform }}
           BACKEND: ${{ matrix.backend }}
@@ -128,7 +131,6 @@ jobs:
           name: screenshots ${{ runner.os }}
           path: screenshots
 
-
   deploy:
     # this will run when you have tagged a commit, starting with "v*"
     # and requires that you have put your twine API key in your