added tests for LazyTableReference init and str

Author: dantownsend

tests/columns/test_reference.py

@@ -0,0 +1,48 @@
+"""
+Most of the tests for piccolo/columns/reference.py are covered in
+piccolo/columns/test_foreignkey.py
+"""
+from unittest import TestCase
+
+from piccolo.columns.reference import LazyTableReference
+
+
+class TestLazyTableReference(TestCase):
+    def test_init(self):
+        """
+        A ``LazyTableReference`` must be passed either an ``app_name`` or
+        ``module_path`` argument.
+        """
+        with self.assertRaises(ValueError):
+            LazyTableReference(table_class_name="Manager")
+
+        with self.assertRaises(ValueError):
+            LazyTableReference(
+                table_class_name="Manager",
+                app_name="example_app",
+                module_path="tests.example_app.tables",
+            )
+
+        # Shouldn't raise exceptions:
+        LazyTableReference(
+            table_class_name="Manager", app_name="example_app",
+        )
+        LazyTableReference(
+            table_class_name="Manager", module_path="tests.example_app.tables",
+        )
+
+    def test_str(self):
+        self.assertEqual(
+            LazyTableReference(
+                table_class_name="Manager", app_name="example_app",
+            ).__str__(),
+            "App example_app.Manager",
+        )
+
+        self.assertEqual(
+            LazyTableReference(
+                table_class_name="Manager",
+                module_path="tests.example_app.tables",
+            ).__str__(),
+            "Module tests.example_app.tables.Manager",
+        )