test: make the Python suite green on Windows

tests/python_tests/test_quoted_columns.py

@@ -9,10 +9,22 @@
 from pathlib import Path
 from io import StringIO
 
+def _sql_cli_binary():
+    """Path to the release binary, with the .exe suffix Windows needs.
+
+    Without the suffix the `exists()` check below raised FileNotFoundError and
+    every test in this file silently never ran on a Windows box, while passing
+    in CI. Same fix as tests/comparison/engines.py and
+    test_in_between_operators.py already carry.
+    """
+    base_dir = Path(__file__).parent.parent.parent
+    suffix = ".exe" if sys.platform == "win32" else ""
+    return base_dir / "target" / "release" / f"sql-cli{suffix}"
+
+
 def run_query(query, data_file=None):
     """Execute a query and return the results."""
-    base_dir = Path(__file__).parent.parent.parent
-    sql_cli = base_dir / "target" / "release" / "sql-cli"
+    sql_cli = _sql_cli_binary()
 
     if not sql_cli.exists():
         raise FileNotFoundError(f"sql-cli not found at {sql_cli}")
@@ -37,10 +49,7 @@ def run_query(query, data_file=None):
 
 def format_query(query):
     """Format a SQL query."""
-    base_dir = Path(__file__).parent.parent.parent
-    sql_cli = base_dir / "target" / "release" / "sql-cli"
-
-    cmd = [str(sql_cli), "--format", "-"]
+    cmd = [str(_sql_cli_binary()), "--format", "-"]
     result = subprocess.run(cmd, input=query, capture_output=True, text=True)
 
     if result.returncode != 0:

tests/python_tests/test_sql_comments.py

@@ -14,7 +14,7 @@
 def run_query(query, output_format="json"):
     """Run a SQL query and return the result"""
     cmd = [str(SQL_CLI), str(TEST_DATA), "-q", query, "-o", output_format]
-    result = subprocess.run(cmd, capture_output=True, text=True)
+    result = subprocess.run(cmd, capture_output=True, text=True, encoding='utf-8')
 
     if result.returncode != 0:
         print(f"Command failed: {' '.join(cmd)}")
@@ -34,13 +34,20 @@ def run_query(query, output_format="json"):
 
 def run_query_file(sql_file_content, output_format="json"):
     """Run a SQL query from a file"""
-    with tempfile.NamedTemporaryFile(mode='w', suffix='.sql', delete=False) as f:
+    # encoding='utf-8' is required, not cosmetic: without it Python writes the
+    # temp file in the platform's preferred encoding, which is cp1252 on
+    # Windows, and the scientific-notation tests below (a₀, π, ε₀, ℏ) raise
+    # UnicodeEncodeError before the CLI is ever invoked. The CLI reads .sql
+    # files as UTF-8 on every platform, so this also makes the two agree.
+    with tempfile.NamedTemporaryFile(
+        mode='w', suffix='.sql', delete=False, encoding='utf-8'
+    ) as f:
         f.write(sql_file_content)
         temp_path = f.name
 
     try:
         cmd = [str(SQL_CLI), str(TEST_DATA), "-f", temp_path, "-o", output_format]
-        result = subprocess.run(cmd, capture_output=True, text=True)
+        result = subprocess.run(cmd, capture_output=True, text=True, encoding='utf-8')
 
         if result.returncode != 0:
             print(f"Command failed: {' '.join(cmd)}")

tests/python_tests/test_unnest.py

@@ -7,16 +7,22 @@
 import json
 import csv
 import os
+import sys
 import tempfile
 import pytest
 from pathlib import Path
 
-# Find the sql-cli binary
+# Find the sql-cli binary. The .exe suffix is required on Windows: without it
+# the release `exists()` check fails, this file quietly falls through to the
+# debug path, and Windows then resolves `sql-cli` -> `sql-cli.exe` anyway — so
+# the tests pass while exercising the DEBUG binary. That is worse than the
+# outright failure the same omission caused in test_quoted_columns.py.
 PROJECT_ROOT = Path(__file__).parent.parent.parent
-SQL_CLI = PROJECT_ROOT / "target" / "release" / "sql-cli"
+_SUFFIX = ".exe" if sys.platform == "win32" else ""
+SQL_CLI = PROJECT_ROOT / "target" / "release" / f"sql-cli{_SUFFIX}"
 
 if not SQL_CLI.exists():
-    SQL_CLI = PROJECT_ROOT / "target" / "debug" / "sql-cli"
+    SQL_CLI = PROJECT_ROOT / "target" / "debug" / f"sql-cli{_SUFFIX}"
 
 
 def run_query(csv_file, query):

tests/python_tests/test_web_cte_advanced.py

@@ -46,13 +46,20 @@ def test_method_parsing():
         )
         SELECT 1 as test
         """
-        # Just check that it parses without error by using --query-plan
-        # Don't actually execute the query
+        # Check that it parses, via --query-plan.
+        #
+        # NOTE: --query-plan prints the AST and then runs the query anyway, so
+        # despite the intent above this DOES attempt the fetch. On Linux the
+        # refused connection to a closed localhost port returns instantly; on
+        # Windows it takes ~2.4s, so the original timeout=2 made this the one
+        # test in the file that failed locally while passing in CI. The timeout
+        # is raised rather than tightened because the delay is the CLI's, not
+        # this test's. The real fix is for --query-plan not to execute.
         result = subprocess.run(
             [SQL_CLI, "-q", query, "--query-plan"],
             capture_output=True,
             text=True,
-            timeout=2  # Short timeout for localhost
+            timeout=15
         )
         # Check that parsing succeeded - should show the AST with method
         assert "WebCTESpec" in result.stdout or "method:" in result.stdout.lower(), \