block pyqt 5.15.0.

remove xdist from azure pipelines

tox-azure.ini

@@ -12,10 +12,9 @@ deps =
     -rrequirements/requirements_test.txt
     -rrequirements/requirements_dev.txt
     PyVirtualDisplay<1.0
-    pytest-xdist
     pytest-azurepipelines
     pytest-xvfb ; sys_platform == 'linux'
-    PyQt5: PyQt5
-    PySide2: PySide2
+    PyQt5: PyQt5!=5.15.0
+    PySide2: PySide2!=5.15.0
 commands =
-    pytest package/tests --cov=PartSeg --cov=PartSegCore --cov=PartSegImage --cov-report html -n auto --cov-append --dist=loadfile
+    pytest package/tests --cov=PartSeg --cov=PartSegCore --cov=PartSegImage --cov-report html --cov-append

tox.ini

@@ -14,7 +14,7 @@ deps =
     setuptools_scm[toml]>=3.4
     pytest-xvfb ; sys_platform == 'linux'
     PyVirtualDisplay<1.0
-    PyQt5: PyQt5
+    PyQt5: PyQt5!=5.15.0
     PySide2: PySide2!=5.15.0
 
 commands =