use sys.executable instead of hardcoded python (#5763)

Co-authored-by: Saugat Pachhai (सौगात) <[email protected]>

tests/__main__.py

@@ -14,7 +14,7 @@ os.putenv(
 )
 os.putenv("DVC_HOME", REPO_ROOT)
 
+opts = "-v -n=auto --dist loadscope --cov=dvc --durations=0"
 params = " ".join(sys.argv[1:])
-
-cmd = f"pytest -v -n=auto --dist loadscope --cov=dvc --durations=0 {params}"
+cmd = f"{sys.executable} -m pytest {opts} {params}"
 check_call(cmd, shell=True)

tests/unit/test_imports.py

@@ -1,4 +1,5 @@
 import subprocess
+import sys
 
 
 def test_no_remote_imports():
@@ -15,7 +16,7 @@ def test_no_remote_imports():
 
     code = "import dvc.main, sys; print(' '.join(sys.modules))"
     res = subprocess.run(
-        ["python", "-c", code], stdout=subprocess.PIPE, check=True
+        [sys.executable, "-c", code], stdout=subprocess.PIPE, check=True
     )
     modules = res.stdout.decode().split()
     assert not set(modules) & remote_modules