diff --git a/src/ptpython/completer.py b/src/ptpython/completer.py
index 40701ca..b15e385 100644
--- a/src/ptpython/completer.py
+++ b/src/ptpython/completer.py
@@ -130,10 +130,10 @@ def double_quoted_wrapper(text: str) -> str:
         )
 
     def _complete_path_while_typing(self, document: Document) -> bool:
-        char_before_cursor = document.char_before_cursor
+        text = document.text_before_cursor
+        char_before_cursor = text[-1:]
         return bool(
-            document.text
-            and (char_before_cursor.isalnum() or char_before_cursor in "/.~")
+            text and (char_before_cursor.isalnum() or char_before_cursor in "/.~")
         )
 
     def _complete_python_while_typing(self, document: Document) -> bool:
diff --git a/src/ptpython/utils.py b/src/ptpython/utils.py
index 92cfc2a..4b40a71 100644
--- a/src/ptpython/utils.py
+++ b/src/ptpython/utils.py
@@ -59,7 +59,7 @@ def has_unclosed_brackets(text: str) -> bool:
 
 def get_jedi_script_from_document(
     document: Document, locals: dict[str, Any], globals: dict[str, Any]
-) -> Interpreter:
+) -> Interpreter | None:
     import jedi  # We keep this import in-line, to improve start-up time.
 
     # Importing Jedi is 'slow'.
diff --git a/tests/test_completer_utils.py b/tests/test_completer_utils.py
new file mode 100644
index 0000000..b75203c
--- /dev/null
+++ b/tests/test_completer_utils.py
@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+from prompt_toolkit.document import Document
+
+from ptpython.completer import PythonCompleter
+from ptpython.utils import get_jedi_script_from_document
+
+
+def test_complete_path_while_typing_empty_or_whitespace() -> None:
+    completer = PythonCompleter(
+        get_globals=lambda: {},
+        get_locals=lambda: {},
+        enable_dictionary_completion=lambda: True,
+    )
+    # Empty document.
+    assert completer._complete_path_while_typing(Document("")) is False
+    # Whitespace-only.
+    assert completer._complete_path_while_typing(Document("   ")) is False
+    # Newline-only.
+    assert completer._complete_path_while_typing(Document("\n")) is False
+    # Cursor at start of non-empty text.
+    assert completer._complete_path_while_typing(Document("hello/", cursor_position=0)) is False
+
+
+def test_complete_path_while_typing_valid_paths() -> None:
+    completer = PythonCompleter(
+        get_globals=lambda: {},
+        get_locals=lambda: {},
+        enable_dictionary_completion=lambda: True,
+    )
+    assert completer._complete_path_while_typing(Document("hello/")) is True
+    assert completer._complete_path_while_typing(Document("~/")) is True
+    assert completer._complete_path_while_typing(Document("./")) is True
+
+
+def test_get_jedi_script_from_document_return_annotation() -> None:
+    assert get_jedi_script_from_document.__annotations__["return"] == "Interpreter | None"