diff --git a/pyproject.toml b/pyproject.toml
index bc36dee..50dd6f4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,6 +34,13 @@ pytest = "^7.4.3"
 [tool.poetry.scripts]
 vyper-lsp = 'vyper_lsp.main:main'
 
+[tool.coverage.run]
+source = ["vyper_lsp"]
+omit = ["vyper_lsp/analyzer/SourceAnalyzer.py",
+        "vyper_lsp/__init__.py",
+        "vyper_lsp/__main__.py",
+        ]
+
 [build-system]
 requires = ["poetry-core>=1.0.0"]
 build-backend = "poetry.core.masonry.api"
diff --git a/tests/test_debouncer.py b/tests/test_debouncer.py
new file mode 100644
index 0000000..3ca1749
--- /dev/null
+++ b/tests/test_debouncer.py
@@ -0,0 +1,21 @@
+import time
+from vyper_lsp.debounce import Debouncer  # Import Debouncer from your module
+
+
+def test_debounce():
+    result = []
+
+    def test_function(arg):
+        result.append(arg)
+
+    debouncer = Debouncer(wait=0.5)
+    debounced_func = debouncer.debounce(test_function)
+
+    debounced_func("first call")
+    time.sleep(0.2)  # Sleep for less than the debounce period
+    debounced_func("second call")
+    time.sleep(
+        0.6
+    )  # Sleep for more than the debounce period to allow the function to execute
+
+    assert result == ["second call"]
diff --git a/tests/test_utils.py b/tests/test_utils.py
index fe5cc11..8904b8c 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -24,3 +24,19 @@ def test_get_expression_at_cursor():
     assert utils.get_expression_at_cursor(text, 0) == "foo_bar"
     assert utils.get_expression_at_cursor(text, 4) == "foo_bar"
     assert utils.get_expression_at_cursor(text, 21) == "self.baz (1,2,3)"
+
+
+def test_get_internal_fn_name_at_cursor():
+    text = "self.foo = 123"
+    assert utils.get_internal_fn_name_at_cursor(text, 0) is None
+    assert utils.get_internal_fn_name_at_cursor(text, 1) is None
+    assert utils.get_internal_fn_name_at_cursor(text, 5) is None
+    assert utils.get_internal_fn_name_at_cursor(text, 12) is None
+
+    text = "foo_bar = self.baz (1,2,3)"
+    assert utils.get_internal_fn_name_at_cursor(text, 0) is None
+    assert utils.get_internal_fn_name_at_cursor(text, 4) is None
+    assert utils.get_internal_fn_name_at_cursor(text, 21) == "baz"
+
+    text = "self.foo(self.bar())"
+    assert utils.get_internal_fn_name_at_cursor(text, 0) == "foo"
diff --git a/vyper_lsp/utils.py b/vyper_lsp/utils.py
index 27dff38..4e9551a 100644
--- a/vyper_lsp/utils.py
+++ b/vyper_lsp/utils.py
@@ -139,9 +139,9 @@ def get_expression_at_cursor(sentence: str, cursor_index: int) -> str:
 def get_internal_fn_name_at_cursor(sentence: str, cursor_index: int) -> str:
     # TODO: dont assume the fn call is at the end of the line
     # REVIEW: make cases like self.foo(self.bar()) work
-    word = sentence.split("(")[0].split(" ")[-1].strip().split("self.")[-1]
-
-    return word
+    expression = get_expression_at_cursor(sentence, cursor_index)
+    if is_internal_fn(expression):
+        return expression.split(".")[1].split("(")[0].strip()
 
 
 def extract_enum_name(line: str):