Refactor work with env variables (#8208)

* del MO_ROOT

* del MO_ROOT from common_utils.py

* add MO_PATH to common_utils.py

* change mo_path

tests/layer_tests/common/constants.py

@@ -4,14 +4,6 @@
 import os
 
 
-if 'MO_ROOT' in os.environ:
-    mo_bin = os.environ['MO_ROOT']
-    if not os.path.exists(mo_bin):
-        raise EnvironmentError(
-            "Environment variable MO_ROOT points to non existing path {}".format(mo_bin))
-else:
-    raise EnvironmentError("MO_ROOT variable is not set")
-
 if os.environ.get('OUTPUT_DIR') is not None:
     out_path = os.environ['OUTPUT_DIR']
 else:

tests/layer_tests/common/utils/common_utils.py

@@ -2,24 +2,24 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import logging
-import os
 import subprocess
 import sys
+from pathlib import Path
 
+import mo
 import numpy as np
 
-
 logger = logging.getLogger(__name__)
 
 
 def generate_ir(coverage=False, **kwargs):
-    # Get default mo args
-    mo = os.path.join(os.environ.get("MO_ROOT"), "mo.py")
+    mo_path = Path(mo.__file__).parent
+    mo_runner = mo_path.joinpath('main.py').as_posix()
     if coverage:
-        params = [sys.executable, '-m', 'coverage', 'run', '-p', '--source={}'.format(os.environ.get("MO_ROOT")),
-                  '--omit=*_test.py', mo]
+        params = [sys.executable, '-m', 'coverage', 'run', '-p', '--source={}'.format(mo_path.parent),
+                  '--omit=*_test.py', mo_runner]
     else:
-        params = [sys.executable, mo]
+        params = [sys.executable, mo_runner]
     for key, value in kwargs.items():
         if key == "batch":
             params.extend(("-b", str(value)))