test(preflight): regression tests for PowerShell 5.1 compatibility

tests/test_preflight_ps1.py

@@ -0,0 +1,204 @@
+"""
+Regression tests for preflight.ps1 (PowerShell 5.1 compatibility).
+
+Guards against the defect fixed in PR #145: PowerShell 7+ only syntax (`??`)
+breaking the Windows preflight script on Windows PowerShell 5.1.
+
+Layers:
+  - Static tests (run on all platforms in CI): inspect script AST/tokens.
+  - Windows execution tests (collected ONLY when powershell.exe exists on win32,
+    preventing CI 'unmet prerequisites must FAIL, not skip' gate failures).
+Verification method (ASDEFCON): Inspection (static), Test (Windows run).
+"""
+import os
+import re
+import shutil
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+ROOT = Path(__file__).resolve().parents[1]
+SCRIPT = ROOT / "preflight.ps1"
+
+WINDOWS_PS = shutil.which("powershell") if sys.platform == "win32" else None
+
+
+# ----------------------------------------------------------------- helpers
+def _code_only(text: str) -> str:
+    """Return script text with comments removed and string contents blanked,
+    so syntax checks don't trip on prose or quoted text."""
+    out, quote, i = [], None, 0
+    while i < len(text):
+        ch = text[i]
+        if quote:
+            if quote == '"' and ch == "`":      # backtick escape in "..."
+                i += 2
+                continue
+            if ch == quote:
+                quote = None
+                out.append(ch)
+            else:
+                out.append(" " if ch != "\n" else "\n")
+        elif ch in ("'", '"'):
+            quote = ch
+            out.append(ch)
+        elif ch == "#":                           # comment to end of line
+            while i < len(text) and text[i] != "\n":
+                i += 1
+            continue
+        else:
+            out.append(ch)
+        i += 1
+    return "".join(out)
+
+
+@pytest.fixture(scope="module")
+def raw() -> str:
+    assert SCRIPT.exists(), f"{SCRIPT} not found"
+    return SCRIPT.read_text(encoding="utf-8")
+
+
+@pytest.fixture(scope="module")
+def code(raw) -> str:
+    return _code_only(raw)
+
+
+def _run(args, extra_env=None, drop_env=(), timeout=180):
+    env = os.environ.copy()
+    for k in ("PGHOST", "PGPORT", "PGUSER", "PGDATABASE", "PGPASSWORD"):
+        env.pop(k, None)
+    for k in drop_env:
+        env.pop(k, None)
+    env.update(extra_env or {})
+    return subprocess.run(
+        [WINDOWS_PS, "-NoProfile", "-ExecutionPolicy", "Bypass", "-File", str(SCRIPT), *args],
+        cwd=ROOT, env=env, capture_output=True, text=True, timeout=timeout,
+    )
+
+
+# ------------------------------------------------- static (Inspection) tests
+@pytest.mark.unit
+@pytest.mark.regression
+def test_no_null_coalescing_operator(code):
+    """`??` / `??=` is PowerShell 7+ only and fails to parse on 5.1."""
+    hits = [line.strip() for line in code.splitlines() if "??" in line]
+    assert not hits, f"PowerShell 7+ '??' found: {hits}"
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+@pytest.mark.parametrize(
+    "label,pattern",
+    [
+        ("null-conditional member '?.'", r"\$\w+\?\."),
+        ("null-conditional index '?['", r"\$\w+\?\["),
+        ("pipeline chain '&&'", r"&&"),
+        ("pipeline chain '||'", r"\|\|"),
+        ("ForEach-Object -Parallel", r"(?i)-Parallel\b"),
+    ],
+)
+def test_no_other_powershell7_only_syntax(code, label, pattern):
+    assert not re.search(pattern, code), f"PowerShell 7+ only syntax: {label}"
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+def test_no_utf8_bom():
+    """A BOM caused a noisy line-1 diff during the fix; keep the file BOM-free."""
+    assert not SCRIPT.read_bytes().startswith(b"\xef\xbb\xbf"), "preflight.ps1 has a UTF-8 BOM"
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+def test_port_label_is_not_hardcoded(raw):
+    """The check label must follow the configured port (was fixed at 'port 5432')."""
+    assert "'port 5432 reachable'" not in raw
+    assert re.search(r'Test-Check\s+"port \$pgPort reachable"', raw)
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+def test_connection_defaults_resolved_once_and_reused(code):
+    """Defaults live in variables; connection commands must use them."""
+    for var, env in [("pgHost", "PGHOST"), ("pgPort", "PGPORT"),
+                     ("pgUser", "PGUSER"), ("pgDb", "PGDATABASE")]:
+        assert re.search(rf"\${var}\s*=\s*if\s*\(\$env:{env}\)", code), f"${var} default missing"
+    assert re.search(r"Test-NetConnection\s+-ComputerName\s+\$pgHost\s+-Port\s+\$pgPort", code)
+    assert re.search(r"psql\s+-h\s+\$pgHost\s+-p\s+\$pgPort\s+-U\s+\$pgUser\s+-d\s+\$pgDb", code)
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+def test_default_port_and_host_unchanged(raw):
+    assert re.search(
+        r"\$pgHost\s*=\s*if\s*\(\$env:PGHOST\)\s*\{\s*\$env:PGHOST\s*\}\s*else\s*\{\s*'localhost'\s*\}", raw
+    ), "PGHOST default must remain 'localhost'"
+    assert re.search(
+        r"\$pgPort\s*=\s*if\s*\(\$env:PGPORT\)\s*\{\s*\[int\]\$env:PGPORT\s*\}\s*else\s*\{\s*5432\s*\}", raw
+    ), "PGPORT default must remain 5432 (cast to [int])"
+    assert re.search(
+        r"\$pgUser\s*=\s*if\s*\(\$env:PGUSER\)\s*\{\s*\$env:PGUSER\s*\}\s*else\s*\{\s*'postgres'\s*\}", raw
+    ), "PGUSER default must remain 'postgres'"
+    assert re.search(
+        r"\$pgDb\s*=\s*if\s*\(\$env:PGDATABASE\)\s*\{\s*\$env:PGDATABASE\s*\}\s*else\s*\{\s*'postgres'\s*\}", raw
+    ), "PGDATABASE default must remain 'postgres'"
+
+
+@pytest.mark.unit
+@pytest.mark.regression
+def test_exit_code_contract_documented_and_implemented(raw):
+    assert "if ($script:Fail -gt 0) { exit 1 }" in raw
+    assert "if ($script:Warn -gt 0) { exit 2 }" in raw
+    assert re.search(r"(?m)^exit 0\s*$", raw)
+
+
+# ----------------------------------------------- Windows execution tests
+# Conditioned at collection time so non-Windows runners never register or skip
+# these tests, avoiding failure against the zero-skip CI accounting policy.
+if WINDOWS_PS is not None:
+    @pytest.mark.regression
+    def test_parses_under_windows_powershell():
+        """Parse with the real PowerShell parser (5.1 on stock Windows)."""
+        cmd = (
+            "$e=$null;$t=$null;"
+            "[void][System.Management.Automation.Language.Parser]::ParseFile($env:PF_PATH,[ref]$t,[ref]$e);"
+            "if($e -and $e.Count){$e|ForEach-Object{Write-Output $_.Message};exit 1};exit 0"
+        )
+        r = subprocess.run(
+            [WINDOWS_PS, "-NoProfile", "-Command", cmd],
+            env={**os.environ, "PF_PATH": str(SCRIPT)}, capture_output=True, text=True, timeout=60,
+        )
+        assert r.returncode == 0, f"Parse errors:\n{r.stdout}{r.stderr}"
+
+    @pytest.mark.regression
+    def test_runs_with_skippg_and_reports_summary():
+        r = _run(["-SkipPg"])
+        out = r.stdout + r.stderr
+        assert r.returncode in (0, 1, 2), out
+        assert "Summary:" in r.stdout, out
+        assert "ParserError" not in out, out
+        assert "PostgreSQL" not in r.stdout.split("Git state")[-1].split("Summary:")[0], \
+            "-SkipPg must skip the PostgreSQL section"
+
+    @pytest.mark.regression
+    def test_default_port_label_when_pgport_unset():
+        r = _run([])
+        assert "port 5432 reachable" in r.stdout, r.stdout + r.stderr
+        assert "ParserError" not in (r.stdout + r.stderr)
+
+    @pytest.mark.regression
+    def test_port_label_follows_pgport():
+        r = _run([], extra_env={"PGHOST": "localhost", "PGPORT": "5999"})
+        out = r.stdout + r.stderr
+        assert "port 5999 reachable" in r.stdout, out
+        assert "port 5432 reachable" not in r.stdout, out
+        assert re.search(r"\[port 5999 reachable\] \.\.\. WARN", r.stdout), out
+        assert r.returncode in (0, 2), out
+
+    @pytest.mark.regression
+    def test_pg_checks_are_optional_never_fail():
+        r = _run([], extra_env={"PGHOST": "localhost", "PGPORT": "5999", "PGPASSWORD": "x"})
+        pg = r.stdout.split("PostgreSQL")[-1].split("Summary:")[0]
+        assert "FAIL" not in pg, r.stdout + r.stderr