Add string operator $trim/$ltrim/$rtrim 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/ltrim/test_ltrim_custom_chars.py

@@ -0,0 +1,180 @@
+from __future__ import annotations
+
+import pytest
+
+from documentdb_tests.compatibility.tests.core.operator.expressions.utils.utils import (
+    execute_expression,
+)
+from documentdb_tests.framework.assertions import assertResult
+from documentdb_tests.framework.parametrize import pytest_params
+
+from .utils.ltrim_common import (
+    LtrimTest,
+    _expr,
+)
+
+# Property [Custom Chars]: when chars is provided, only those characters are trimmed from the
+# leading edge. Each character in chars is treated individually (not as a substring), and the
+# order of characters in chars does not affect the result.
+LTRIM_CUSTOM_CHARS_TESTS: list[LtrimTest] = [
+    LtrimTest(
+        "custom_single_char",
+        input="aaahello",
+        chars="a",
+        expected="hello",
+        msg="$ltrim should trim leading occurrences of a single custom char",
+    ),
+    LtrimTest(
+        "custom_repeated_single",
+        input="xxxhello",
+        chars="x",
+        expected="hello",
+        msg="$ltrim should trim repeated leading custom char",
+    ),
+    # Custom chars completely replaces the default whitespace set.
+    LtrimTest(
+        "custom_spaces_not_trimmed",
+        input="  xxxhello",
+        chars="x",
+        expected="  xxxhello",
+        msg="$ltrim should not trim spaces when custom chars replaces default set",
+    ),
+    LtrimTest(
+        "custom_tabs_not_trimmed",
+        input="\t\txxxhello",
+        chars="x",
+        expected="\t\txxxhello",
+        msg="$ltrim should not trim tabs when custom chars replaces default set",
+    ),
+    # Duplicate characters in chars have no additional effect.
+    LtrimTest(
+        "custom_duplicate_chars",
+        input="aaahello",
+        chars="aab",
+        expected="hello",
+        msg="$ltrim should ignore duplicate characters in chars",
+    ),
+    # Each character in chars is treated individually, not as a substring pattern.
+    LtrimTest(
+        "custom_individual_any_order",
+        input="cbahello",
+        chars="abc",
+        expected="hello",
+        msg="$ltrim should treat each char in chars individually, not as a substring",
+    ),
+    LtrimTest(
+        "custom_individual_mixed_repeats",
+        input="aabbcchello",
+        chars="abc",
+        expected="hello",
+        msg="$ltrim should trim mixed repeats of individual chars",
+    ),
+    # Characters not in chars are preserved.
+    LtrimTest(
+        "custom_no_match",
+        input="xhello",
+        chars="a",
+        expected="xhello",
+        msg="$ltrim should preserve leading chars not in the trim set",
+    ),
+    # Order of characters in chars does not affect the result.
+    LtrimTest(
+        "custom_order_abc",
+        input="bcaahello",
+        chars="abc",
+        expected="hello",
+        msg="$ltrim should produce same result regardless of chars order (abc)",
+    ),
+    LtrimTest(
+        "custom_order_cba",
+        input="bcaahello",
+        chars="cba",
+        expected="hello",
+        msg="$ltrim should produce same result regardless of chars order (cba)",
+    ),
+    LtrimTest(
+        "custom_order_bac",
+        input="bcaahello",
+        chars="bac",
+        expected="hello",
+        msg="$ltrim should produce same result regardless of chars order (bac)",
+    ),
+]
+
+
+# Property [Directionality]: only leading (left-side) characters are trimmed. Trailing characters
+# matching the trim set are preserved.
+LTRIM_DIRECTIONALITY_TESTS: list[LtrimTest] = [
+    LtrimTest(
+        "dir_trailing_spaces",
+        input="hello   ",
+        expected="hello   ",
+        msg="$ltrim should preserve trailing spaces",
+    ),
+    LtrimTest(
+        "dir_leading_trimmed_trailing_kept",
+        input="  hello  ",
+        expected="hello  ",
+        msg="$ltrim should trim leading spaces while preserving trailing spaces",
+    ),
+    LtrimTest(
+        "dir_custom_trailing_kept",
+        input="aaahelloaaa",
+        chars="a",
+        expected="helloaaa",
+        msg="$ltrim should trim leading custom chars while preserving trailing ones",
+    ),
+    LtrimTest(
+        "dir_trailing_tab_kept",
+        input="\thello\t",
+        expected="hello\t",
+        msg="$ltrim should trim leading tab while preserving trailing tab",
+    ),
+    # First character not in trim set stops all trimming.
+    LtrimTest(
+        "dir_first_char_not_in_set",
+        input="hxexlxlxo",
+        chars="x",
+        expected="hxexlxlxo",
+        msg="$ltrim should not trim when first character is not in the trim set",
+    ),
+]
+
+# Property [Whitespace Subset Chars]: when chars is a subset of whitespace characters, only
+# those specific whitespace characters are trimmed; other whitespace is preserved.
+LTRIM_WHITESPACE_SUBSET_TESTS: list[LtrimTest] = [
+    LtrimTest(
+        "subset_tab_only",
+        input="\t hello \t",
+        chars="\t",
+        expected=" hello \t",
+        msg="$ltrim with chars=tab should trim only leading tabs, preserving spaces",
+    ),
+    LtrimTest(
+        "subset_space_tab",
+        input=" \t\nhello\n\t ",
+        chars=" \t",
+        expected="\nhello\n\t ",
+        msg="$ltrim with chars=space+tab should preserve leading newlines",
+    ),
+    LtrimTest(
+        "subset_newline_only",
+        input="\n\n hello",
+        chars="\n",
+        expected=" hello",
+        msg="$ltrim with chars=newline should trim only leading newlines, preserving spaces",
+    ),
+]
+
+LTRIM_CUSTOM_CHARS_ALL_TESTS = (
+    LTRIM_CUSTOM_CHARS_TESTS + LTRIM_DIRECTIONALITY_TESTS + LTRIM_WHITESPACE_SUBSET_TESTS
+)
+
+
+@pytest.mark.parametrize("test_case", pytest_params(LTRIM_CUSTOM_CHARS_ALL_TESTS))
+def test_ltrim_custom_chars(collection, test_case: LtrimTest):
+    """Test $ltrim custom chars and directionality cases."""
+    result = execute_expression(collection, _expr(test_case))
+    assertResult(
+        result, expected=test_case.expected, error_code=test_case.error_code, msg=test_case.msg
+    )