Add prepare_url_slash to string_helpers.py and tests

Function cleans up url paths (without domain) by ensuring they start with a single slash and removing double slashes.

tests/unit/string_handling/test_string_helpers.py

@@ -5,7 +5,7 @@ PyTest: string_handling/string_helpers
 from textwrap import shorten
 import pytest
 from corelibs.string_handling.string_helpers import (
-    shorten_string, left_fill, format_number
+    shorten_string, left_fill, format_number, prepare_url_slash
 )
 
 
@@ -191,6 +191,75 @@ class TestFormatNumber:
         assert result == "0.001"
 
 
+class TestPrepareUrlSlash:
+    """Tests for prepare_url_slash function"""
+
+    def test_url_without_leading_slash(self):
+        """Test that URL without leading slash gets one added"""
+        result = prepare_url_slash("api/users")
+        assert result == "/api/users"
+
+    def test_url_with_leading_slash(self):
+        """Test that URL with leading slash remains unchanged"""
+        result = prepare_url_slash("/api/users")
+        assert result == "/api/users"
+
+    def test_url_with_double_slashes(self):
+        """Test that double slashes are reduced to single slash"""
+        result = prepare_url_slash("/api//users")
+        assert result == "/api/users"
+
+    def test_url_with_multiple_slashes(self):
+        """Test that multiple consecutive slashes are reduced to single slash"""
+        result = prepare_url_slash("api///users////data")
+        assert result == "/api/users/data"
+
+    def test_url_with_leading_double_slash(self):
+        """Test URL starting with double slash"""
+        result = prepare_url_slash("//api/users")
+        assert result == "/api/users"
+
+    def test_url_without_slash_and_double_slashes(self):
+        """Test URL without leading slash and containing double slashes"""
+        result = prepare_url_slash("api//users//data")
+        assert result == "/api/users/data"
+
+    def test_single_slash(self):
+        """Test single slash URL"""
+        result = prepare_url_slash("/")
+        assert result == "/"
+
+    def test_multiple_slashes_only(self):
+        """Test URL with only multiple slashes"""
+        result = prepare_url_slash("///")
+        assert result == "/"
+
+    def test_empty_string(self):
+        """Test empty string"""
+        result = prepare_url_slash("")
+        assert result == "/"
+
+    def test_url_with_query_params(self):
+        """Test URL with query parameters"""
+        result = prepare_url_slash("/api/users?id=1")
+        assert result == "/api/users?id=1"
+
+    def test_url_with_double_slashes_and_query(self):
+        """Test URL with double slashes and query parameters"""
+        result = prepare_url_slash("api//users?id=1")
+        assert result == "/api/users?id=1"
+
+    def test_complex_url_path(self):
+        """Test complex URL path with multiple segments"""
+        result = prepare_url_slash("api/v1/users/123/profile")
+        assert result == "/api/v1/users/123/profile"
+
+    def test_complex_url_with_multiple_issues(self):
+        """Test URL with both missing leading slash and multiple double slashes"""
+        result = prepare_url_slash("api//v1///users//123////profile")
+        assert result == "/api/v1/users/123/profile"
+
+
 # Additional integration tests
 class TestIntegration:
     """Integration tests combining functions"""
@@ -236,4 +305,23 @@ def test_format_number_parametrized(number: float | int, precision: int, expecte
     """Parametrized test for format_number"""
     assert format_number(number, precision) == expected
 
+
+@pytest.mark.parametrize("input_url,expected", [
+    ("api/users", "/api/users"),
+    ("/api/users", "/api/users"),
+    ("api//users", "/api/users"),
+    ("/api//users", "/api/users"),
+    ("//api/users", "/api/users"),
+    ("api///users////data", "/api/users/data"),
+    ("/", "/"),
+    ("///", "/"),
+    ("", "/"),
+    ("api/v1/users/123", "/api/v1/users/123"),
+    ("/api/users?id=1&name=test", "/api/users?id=1&name=test"),
+    ("api//users//123//profile", "/api/users/123/profile"),
+])
+def test_prepare_url_slash_parametrized(input_url: str, expected: str):
+    """Parametrized test for prepare_url_slash"""
+    assert prepare_url_slash(input_url) == expected
+
 # __END__