Consistently use sys.executable to run subprocesses

In some scenarios, like running pytest outside of an active virtualenv,
it could happen that "coverage" would refer to a different Python
interpreter than the one running the tests. Admittedly that does not
happen in standard development scenarios where you use a virtualenv. But
it easily happens when packaging for Linux distributions that support
multiple versions of Python and it can also happen when running pytest
from a virtualenv without activating it. The latter is something that's
convenient when testing versus multiple Python versions without using
tox.

Explicitly invoking coverage as a module on sys.executable ensures that
the same binary, not process, that's also running the tests is used.
This was in fact already done in some tests but not consistently across
all of them.

tests/test_compat/test_option_get_help.py

@@ -1,5 +1,6 @@
 import os
 import subprocess
+import sys
 
 from typer.testing import CliRunner
 
@@ -26,7 +27,7 @@ def test_coverage_call():
 
 def test_completion():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",

tests/test_completion/test_completion.py

@@ -47,7 +47,7 @@ def test_install_completion():
 
 def test_completion_invalid_instruction():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -63,7 +63,7 @@ def test_completion_invalid_instruction():
 
 def test_completion_source_bash():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -81,7 +81,7 @@ def test_completion_source_bash():
 
 def test_completion_source_invalid_shell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -96,7 +96,7 @@ def test_completion_source_invalid_shell():
 
 def test_completion_source_invalid_instruction():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -111,7 +111,7 @@ def test_completion_source_invalid_instruction():
 
 def test_completion_source_zsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -126,7 +126,7 @@ def test_completion_source_zsh():
 
 def test_completion_source_fish():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -141,7 +141,7 @@ def test_completion_source_fish():
 
 def test_completion_source_powershell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -159,7 +159,7 @@ def test_completion_source_powershell():
 
 def test_completion_source_pwsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__],
+        [sys.executable, "-m", "coverage", "run", mod.__file__],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",

tests/test_completion/test_completion_complete.py

@@ -1,12 +1,13 @@
 import os
 import subprocess
+import sys
 
 from docs_src.commands.help import tutorial001 as mod
 
 
 def test_completion_complete_subcommand_bash():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -23,7 +24,7 @@ def test_completion_complete_subcommand_bash():
 
 def test_completion_complete_subcommand_bash_invalid():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -40,7 +41,7 @@ def test_completion_complete_subcommand_bash_invalid():
 
 def test_completion_complete_subcommand_zsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -59,7 +60,7 @@ def test_completion_complete_subcommand_zsh():
 
 def test_completion_complete_subcommand_zsh_files():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -75,7 +76,7 @@ def test_completion_complete_subcommand_zsh_files():
 
 def test_completion_complete_subcommand_fish():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -95,7 +96,7 @@ def test_completion_complete_subcommand_fish():
 
 def test_completion_complete_subcommand_fish_should_complete():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -112,7 +113,7 @@ def test_completion_complete_subcommand_fish_should_complete():
 
 def test_completion_complete_subcommand_fish_should_complete_no():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -129,7 +130,7 @@ def test_completion_complete_subcommand_fish_should_complete_no():
 
 def test_completion_complete_subcommand_powershell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -147,7 +148,7 @@ def test_completion_complete_subcommand_powershell():
 
 def test_completion_complete_subcommand_pwsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -165,7 +166,7 @@ def test_completion_complete_subcommand_pwsh():
 
 def test_completion_complete_subcommand_noshell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",

tests/test_completion/test_completion_complete_no_help.py

@@ -1,12 +1,13 @@
 import os
 import subprocess
+import sys
 
 from docs_src.commands.index import tutorial002 as mod
 
 
 def test_completion_complete_subcommand_zsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -23,7 +24,7 @@ def test_completion_complete_subcommand_zsh():
 
 def test_completion_complete_subcommand_fish():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -40,7 +41,7 @@ def test_completion_complete_subcommand_fish():
 
 def test_completion_complete_subcommand_powershell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -56,7 +57,7 @@ def test_completion_complete_subcommand_powershell():
 
 def test_completion_complete_subcommand_pwsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, " "],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, " "],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",

tests/test_completion/test_completion_install.py

@@ -1,5 +1,6 @@
 import os
 import subprocess
+import sys
 from pathlib import Path
 from unittest import mock
 
@@ -16,7 +17,7 @@
 
 def test_completion_install_no_shell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--install-completion"],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "--install-completion"],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -39,7 +40,15 @@ def test_completion_install_bash():
     if bash_completion_path.is_file():
         text = bash_completion_path.read_text()
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--install-completion", "bash"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--install-completion",
+            "bash",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -74,7 +83,15 @@ def test_completion_install_zsh():
     if completion_path.is_file():
         text = completion_path.read_text()
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--install-completion", "zsh"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--install-completion",
+            "zsh",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -103,7 +120,15 @@ def test_completion_install_fish():
         Path.home() / f".config/fish/completions/{script_path.name}.fish"
     )
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--install-completion", "fish"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--install-completion",
+            "fish",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",

tests/test_completion/test_completion_show.py

@@ -1,12 +1,13 @@
 import os
 import subprocess
+import sys
 
 from docs_src.first_steps import tutorial001 as mod
 
 
 def test_completion_show_no_shell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion"],
+        [sys.executable, "-m", "coverage", "run", mod.__file__, "--show-completion"],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -25,7 +26,15 @@ def test_completion_show_no_shell():
 
 def test_completion_show_bash():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion", "bash"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--show-completion",
+            "bash",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -43,7 +52,15 @@ def test_completion_show_bash():
 
 def test_completion_source_zsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion", "zsh"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--show-completion",
+            "zsh",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -58,7 +75,15 @@ def test_completion_source_zsh():
 
 def test_completion_source_fish():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion", "fish"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--show-completion",
+            "fish",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -73,7 +98,15 @@ def test_completion_source_fish():
 
 def test_completion_source_powershell():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion", "powershell"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--show-completion",
+            "powershell",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",
@@ -91,7 +124,15 @@ def test_completion_source_powershell():
 
 def test_completion_source_pwsh():
     result = subprocess.run(
-        ["coverage", "run", mod.__file__, "--show-completion", "pwsh"],
+        [
+            sys.executable,
+            "-m",
+            "coverage",
+            "run",
+            mod.__file__,
+            "--show-completion",
+            "pwsh",
+        ],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         encoding="utf-8",