add docs on how to run tests, use sys.executable instead of "python"

README.md

@@ -39,3 +39,10 @@ Suggested code hygiene:
 $ ruff --show-fixes --show-source .
 $ black .
 ```
+
+## Running tests locally
+
+```sh
+python3 -m pip install pytest yamlish junit_xml
+python3 -m pytest
+```

test/_prepare_outputs.py

@@ -1,6 +1,7 @@
 import glob
 import os
 import subprocess
+import sys
 
 from _common import normalize_output
 
@@ -9,7 +10,7 @@
     output = f"test/output/{name}.xml"
     try:
         run = subprocess.run(
-            ["python", "-m", "tap2junit", "-i", file, "-o", output],
+            [sys.executable, "-m", "tap2junit", "-i", file, "-o", output],
             shell=False,
         )
         run.check_returncode()

test/test_outputs.py

@@ -1,6 +1,7 @@
 import glob
 import os
 import subprocess
+import sys
 from pathlib import Path
 
 import pytest
@@ -16,5 +17,5 @@ def test_file(self, tmp_path, file):
         name = os.path.basename(file).replace(".tap", "")
         original = f"./test/output/{name}.xml"
         output = f"{tmp_path}/out.xml"
-        subprocess.run(["python", "-m", "tap2junit", "-i", file, "-o", output])
+        subprocess.run([sys.executable, "-m", "tap2junit", "-i", file, "-o", output])
         assert Path(original).read_text() == normalize_output(Path(output).read_text())