Upstream $tolower/$toupper tests

.github/workflows/pr-tests.yml

@@ -11,7 +11,7 @@ jobs:
 
     services:
       mongodb:
-        image: mongo:8.2
+        image: mongo:8.2.4
         ports:
           - 27017:27017
         options: >-

documentdb_tests/compatibility/tests/core/operator/expressions/string/toLower/test_toLower_arguments.py

@@ -0,0 +1,141 @@
+from __future__ import annotations
+
+import pytest
+
+from documentdb_tests.compatibility.tests.core.operator.expressions.utils.utils import (
+    assert_expression_result,
+    execute_expression,
+    execute_project_with_insert,
+)
+from documentdb_tests.framework.assertions import assertSuccess
+from documentdb_tests.framework.error_codes import (
+    BSON_TO_STRING_CONVERSION_ERROR,
+    EXPRESSION_TYPE_MISMATCH_ERROR,
+    FAILED_TO_PARSE_ERROR,
+    INVALID_DOLLAR_FIELD_PATH,
+)
+from documentdb_tests.framework.parametrize import pytest_params
+
+from .utils.toLower_common import (
+    ToLowerTest,
+    _expr,
+)
+
+# Property [Expression Arguments]: the operator accepts expressions, $literal, and coercible
+# expression results, resolving and coercing them before lowercasing.
+TOLOWER_EXPR_TESTS: list[ToLowerTest] = [
+    ToLowerTest(
+        "expr_toupper_roundtrip",
+        value={"$toUpper": "hello"},
+        expected="hello",
+        msg="$toLower should reverse $toUpper on ASCII letters",
+    ),
+    ToLowerTest(
+        "expr_literal_dollar_sign",
+        value={"$literal": "$HELLO"},
+        expected="$hello",
+        msg="$toLower should lowercase $literal string preserving dollar sign",
+    ),
+    ToLowerTest(
+        "expr_coercible_numeric_result",
+        value={"$add": [1, 2]},
+        expected="3",
+        msg="$toLower should coerce numeric expression result to string",
+    ),
+]
+
+# Property [Arity Success]: a single-element array is unwrapped and processed as the argument,
+# including null and coercible types.
+TOLOWER_ARITY_SUCCESS_TESTS: list[ToLowerTest] = [
+    ToLowerTest(
+        "arity_single_element",
+        value=["HELLO"],
+        expected="hello",
+        msg="$toLower should unwrap single-element string array",
+    ),
+    ToLowerTest(
+        "arity_single_null",
+        value=[None],
+        expected="",
+        msg="$toLower should unwrap single-element null array to empty string",
+    ),
+    ToLowerTest(
+        "arity_single_coercible",
+        value=[42],
+        expected="42",
+        msg="$toLower should unwrap single-element coercible array",
+    ),
+]
+
+# Property [Arity Errors]: an empty array or an array with more than one element produces an
+# error.
+TOLOWER_ARITY_ERROR_TESTS: list[ToLowerTest] = [
+    ToLowerTest(
+        "arity_empty_array",
+        value=[],
+        error_code=EXPRESSION_TYPE_MISMATCH_ERROR,
+        msg="$toLower should reject empty array",
+    ),
+    ToLowerTest(
+        "arity_two_elements",
+        value=["a", "b"],
+        error_code=EXPRESSION_TYPE_MISMATCH_ERROR,
+        msg="$toLower should reject two-element array",
+    ),
+    # Single-element array containing a non-coercible type is unwrapped and errors.
+    ToLowerTest(
+        "arity_single_bool",
+        value=[True],
+        error_code=BSON_TO_STRING_CONVERSION_ERROR,
+        msg="$toLower should reject single-element array with boolean",
+    ),
+]
+
+# Property [Field Path Errors]: bare '$' and '$$' are rejected as invalid field paths.
+TOLOWER_FIELD_PATH_ERROR_TESTS: list[ToLowerTest] = [
+    ToLowerTest(
+        "fieldpath_bare_dollar",
+        value="$",
+        error_code=INVALID_DOLLAR_FIELD_PATH,
+        msg="$toLower should reject bare '$' as invalid field path",
+    ),
+    ToLowerTest(
+        "fieldpath_double_dollar",
+        value="$$",
+        error_code=FAILED_TO_PARSE_ERROR,
+        msg="$toLower should reject '$$' as empty variable name",
+    ),
+]
+
+TOLOWER_ARGUMENT_TESTS = (
+    TOLOWER_EXPR_TESTS
+    + TOLOWER_ARITY_SUCCESS_TESTS
+    + TOLOWER_ARITY_ERROR_TESTS
+    + TOLOWER_FIELD_PATH_ERROR_TESTS
+)
+
+
+@pytest.mark.parametrize("test_case", pytest_params(TOLOWER_ARGUMENT_TESTS))
+def test_tolower_arguments(collection, test_case: ToLowerTest):
+    """Test $toLower argument handling."""
+    result = execute_expression(collection, _expr(test_case))
+    assert_expression_result(
+        result,
+        expected=test_case.expected,
+        error_code=test_case.error_code,
+        msg=test_case.msg,
+    )
+
+
+def test_tolower_document_fields(collection):
+    """Test $toLower reads values from document fields."""
+    result = execute_project_with_insert(
+        collection,
+        {"val": "HELLO WORLD"},
+        {"result": {"$toLower": "$val"}},
+    )
+    assertSuccess(
+        result,
+        [{"result": "hello world"}],
+        msg="$toLower should read values from document fields",
+    )