test-impact: a script test runs by bare interpreter only when it guards its own entry

An unguarded script test that no package script or usage line names was handed
to node or npx tsx, which undid #1570 (a file nothing runs is said so). It still
counts and is selected; only a file with require.main === module, import.meta.main
or a __main__ guard gets its interpreter as the command.

Co-authored-by: axiomcode-bot[bot] <334110751+axiomcode-bot[bot]@users.noreply.github.com>

Author: swapnilpaliwal-sd

plugins/axiomcode/skills/axiomcode/scripts/axiomcode-test-impact

@@ -1430,8 +1430,9 @@ def js_plan(repo, files):
         cmd = _script_for(repo, pkg, f[len(pkg) + 1:] if pkg else f)
         if cmd:
             singles.append((pkg, cmd))
-        elif graph_sql.script_test_file(f, _read(os.path.join(repo, f), 400_000)):
-            # a script test no package script or usage line names runs under its interpreter, never a guessed framework
+        elif graph_sql.script_test_file(f, t := _read(os.path.join(repo, f), 400_000)) and graph_sql.script_main_guard(f, t):
+            # a script test no package script or usage line names runs under its interpreter only when it guards its
+            # own entry; an unguarded one is named as run by nothing (#1570), never a guessed framework or interpreter
             singles.append(('', f"{'npx tsx' if f.endswith(('.ts', '.mts', '.cts', '.tsx')) else 'node'} {shlex.quote(f)}"))
         else:
             unrun.append(f)

plugins/axiomcode/skills/axiomcode/scripts/graph_sql.py

@@ -576,6 +576,20 @@ def script_test_file(rel, text):
     return False
 
 
+# Being a script test says it is a test (counted, selected), not what runs it. Only a file that guards its own entry
+# (`require.main === module`, `import.meta.main`, `__name__ == '__main__'`) says it is meant to run under its bare
+# interpreter; an unguarded one with no package script or usage line naming it is said to be run by nothing (#1570),
+# never handed to an interpreter the project may not have (tsx).
+JS_SCRIPT_MAIN = re.compile(r'\brequire\.main\s*===?\s*module\b|\bmodule\s*===?\s*require\.main\b|\bimport\.meta\.main\b')
+
+
+def script_main_guard(rel, text):
+    """whether the script test `rel` guards its own entry, so its interpreter is the command that runs it"""
+    if not text: return False
+    if rel.endswith('.py'): return PY_SCRIPT_MAIN.search(text) is not None
+    return rel.endswith(JS_SCRIPT_EXT) and JS_SCRIPT_MAIN.search(text) is not None
+
+
 def script_tests(rows, text_of, tm):
     """the module symbols among `rows` ((id, kind, file) of is_test symbols) that are script tests; a file holding a
     test in `tm` is its framework's, never a script"""

tests/cases/javascript/script-runner-is-a-test/case.json

@@ -6,14 +6,18 @@
    "avoid": ["helpers.js (script", "0 of"]},
   {"why": "the runner counts in the summary line: before, the walk reached it and the count said 0 of 0",
    "run": ["impact", "normalize"],
-   "want": ["tests: 3 of 3 test method(s)"]},
+   "want": ["tests: 4 of 4 test method(s)"]},
   {"why": "CONTROL: a runner's setup file has top-level code that reaches the change, and is still not a script test",
    "run": ["impact", "normalize", "--tests"],
    "avoid": ["setup.js (script", "node src/test/setup.js"]},
-  {"why": "a runner no package script names is run by its interpreter, never by a guessed framework",
+  {"why": "a runner no package script names, guarded by `require.main === module`, is run by its interpreter, never by a guessed framework",
    "run": ["impact", "shout", "--tests"],
    "want": ["smoke.js (script: node src/test/smoke.js)", "text.test.js"],
    "avoid": ["run.js"]},
+  {"why": "CONTROL: an unguarded script nothing names still counts as a test, but no interpreter is guessed for it (#1570)",
+   "run": ["impact", "shout", "--tests"],
+   "want": ["loose.js (script: no command found"],
+   "avoid": ["node src/test/loose.js"]},
   {"why": "CONTROL: a helper imported by a framework test is not a script test, and the framework test keeps its selection",
    "run": ["impact", "sample", "--tests"],
    "want": ["text.test.js"],

tests/cases/javascript/script-runner-is-a-test/src/test/loose.js

@@ -0,0 +1,3 @@
+const { shout } = require('../lib/text');
+
+console.log(shout('loose'));

tests/cases/javascript/script-runner-is-a-test/src/test/smoke.js

@@ -1,3 +1,5 @@
 const { shout } = require('../lib/text');
 
-console.log(shout('smoke'));
+if (require.main === module) {
+  console.log(shout('smoke'));
+}