diff --git a/tests/cases/checker/04_custom_types.py b/tests/cases/checker/04_custom_types.py
index 93569b8..c015a75 100644
--- a/tests/cases/checker/04_custom_types.py
+++ b/tests/cases/checker/04_custom_types.py
@@ -1,8 +1,6 @@
 # type: ignore
 # ruff: disable [F821]
 
-midas.using("04_custom_types.midas")
-
 distance: Meter = cast(Meter, 123.45)
 time: Second = cast(Second, 6.7)
 speed = distance / time
diff --git a/tests/cases/python-parser/02_custom_types.py b/tests/cases/python-parser/02_custom_types.py
index 32dbab3..1725bf4 100644
--- a/tests/cases/python-parser/02_custom_types.py
+++ b/tests/cases/python-parser/02_custom_types.py
@@ -2,10 +2,6 @@
 # ruff: disable[F821]
 from __future__ import annotations
 
-import midas
-
-midas.using("02_custom_types.midas")
-
 df: Frame[
     location: GeoLocation
 ]
diff --git a/tests/cases/python-parser/02_custom_types.py.ref.json b/tests/cases/python-parser/02_custom_types.py.ref.json
index 49b861f..639610d 100644
--- a/tests/cases/python-parser/02_custom_types.py.ref.json
+++ b/tests/cases/python-parser/02_custom_types.py.ref.json
@@ -1,26 +1,5 @@
 {
   "stmts": [
-    {
-      "_type": "ExpressionStmt",
-      "expr": {
-        "_type": "CallExpr",
-        "callee": {
-          "_type": "GetExpr",
-          "object": {
-            "_type": "VariableExpr",
-            "name": "midas"
-          },
-          "name": "using"
-        },
-        "arguments": [
-          {
-            "_type": "LiteralExpr",
-            "value": "02_custom_types.midas"
-          }
-        ],
-        "keywords": {}
-      }
-    },
     {
       "_type": "TypeAssign",
       "name": "df",
diff --git a/tests/checker.py b/tests/checker.py
index 0383132..d0a7b3e 100644
--- a/tests/checker.py
+++ b/tests/checker.py
@@ -33,6 +33,10 @@ class CheckerTester(Tester):
         if not path.is_file():
             raise TypeError(f"Test '{path}' is not a file")
 
+        types_paths: list[Path] = []
+        types_path: Path = path.with_suffix(".midas")
+        if types_path.exists():
+            types_paths.append(types_path)
         source: str = path.read_text()
         tree: ast.Module = ast.parse(source, filename=path)
         parser = PythonParser()
@@ -40,7 +44,11 @@ class CheckerTester(Tester):
         resolver = Resolver()
         resolver.resolve(*stmts)
         result: CaseResult = CaseResult()
-        checker = Checker(resolver.locals, file_path=path)
+        checker = Checker(
+            resolver.locals,
+            source_path=path,
+            types_paths=types_paths,
+        )
         diagnostics: list[Diagnostic] = checker.check(stmts)
         for diagnostic in diagnostics:
             result.diagnostics.append(