test: cover method text concatenation

tests/test_validate_typecheck_diagnostics.py

@@ -192,6 +192,12 @@ class ValidateTypecheckDiagnosticsTests(unittest.TestCase):
             MODULE.EXPECTED_OK,
         )
 
+    def test_includes_method_text_concatenation_success_fixture(self):
+        self.assertIn(
+            "tests/typecheck_method_text_concat_good.claro",
+            MODULE.EXPECTED_OK,
+        )
+
     def test_includes_yesno_method_field_assignment_diagnostics(self):
         self.assertIn(
             "tests/typecheck_method_yesno_field_assignment_bad.claro",

tests/typecheck_method_text_concat_good.claro

@@ -0,0 +1,12 @@
+CLASS Player
+    HAS first TEXT
+    HAS last TEXT
+
+    TEACH full_name
+        SET first first + "!"
+        SET last "Dr. " + last
+    END
+END
+
+NEW Player player
+DO player.full_name