appveyor_install: Don't install old PyQt if unneeded

scripts/dev/ci/appveyor_install.py

@@ -28,6 +28,7 @@ CI machines.
 
 from __future__ import print_function
 
+import os
 import time
 import subprocess
 import urllib
@@ -44,23 +45,6 @@ def pip_install(pkg):
                            pkg])
 
 
-print("Getting PyQt5...")
-qt_version = '5.5.1'
-pyqt_version = '5.5.1'
-pyqt_url = ('https://www.qutebrowser.org/pyqt/'
-            'PyQt5-{}-gpl-Py3.4-Qt{}-x32.exe'.format(
-                pyqt_version, qt_version))
-
-try:
-    urllib.urlretrieve(pyqt_url, r'C:\install-PyQt5.exe')
-except (OSError, IOError):
-    print("Downloading PyQt failed, trying again in 10 seconds...")
-    time.sleep(10)
-    urllib.urlretrieve(pyqt_url, r'C:\install-PyQt5.exe')
-
-print("Installing PyQt5...")
-subprocess.check_call([r'C:\install-PyQt5.exe', '/S'])
-
 print("Installing tox")
 pip_install('pip')
 pip_install(r'-rmisc\requirements\requirements-tox.txt')
@@ -69,4 +53,23 @@ print("Linking Python...")
 with open(r'C:\Windows\system32\python3.bat', 'w') as f:
     f.write(r'@C:\Python34\python %*')
 
-check_setup(r'C:\Python34\python')
+
+if '-pyqt' not in os.environ['TESTENV']:
+    print("Getting PyQt5...")
+    qt_version = '5.5.1'
+    pyqt_version = '5.5.1'
+    pyqt_url = ('https://www.qutebrowser.org/pyqt/'
+                'PyQt5-{}-gpl-Py3.4-Qt{}-x32.exe'.format(
+                    pyqt_version, qt_version))
+
+    try:
+        urllib.urlretrieve(pyqt_url, r'C:\install-PyQt5.exe')
+    except (OSError, IOError):
+        print("Downloading PyQt failed, trying again in 10 seconds...")
+        time.sleep(10)
+        urllib.urlretrieve(pyqt_url, r'C:\install-PyQt5.exe')
+
+    print("Installing PyQt5...")
+    subprocess.check_call([r'C:\install-PyQt5.exe', '/S'])
+
+    check_setup(r'C:\Python34\python')