test: agregar tests de GUI con mocks de tkinter

conftest.py

@@ -0,0 +1,82 @@
+import pytest
+import tkinter as tk
+
+class DummyRoot:
+    def __init__(self, *args, **kwargs):
+        self._title = ""
+    def title(self, t=None):
+        if t is not None:
+            self._title = t
+        return self._title
+    def geometry(self, *a, **k):
+        pass
+    def configure(self, *a, **k):
+        pass
+    def grid_rowconfigure(self, *a, **k):
+        pass
+    def grid_columnconfigure(self, *a, **k):
+        pass
+    def mainloop(self):
+        pass
+    def bind(self, *a, **k):
+        pass
+    def after(self, *a, **k):
+        pass
+    def destroy(self):
+        pass
+
+class DummyEntry:
+    def __init__(self, master=None, *args, **kwargs):
+        self._text = ""
+    def grid(self, *a, **k):
+        pass
+    def delete(self, start, end=None):
+        self._text = ""
+    def insert(self, index, text):
+        self._text = str(text)
+    # helper opcional para tests si quieren leer el contenido:
+    def get(self):
+        return self._text
+
+class DummyButton:
+    def __init__(self, master=None, *args, **kwargs):
+        pass
+    def grid(self, *a, **k):
+        pass
+
+class DummyLabel:
+    def __init__(self, master=None, *args, **kwargs):
+        self._text = kwargs.get('text', '')
+    def grid(self, *a, **k):
+        pass
+    def config(self, **kwargs):
+        if 'text' in kwargs:
+            self._text = kwargs['text']
+    def get(self):
+        return self._text
+
+@pytest.fixture(autouse=True)
+def replace_tkinter():
+    """
+    Fixture autouse que sustituye componentes gráficos por dummies durante los tests.
+    Esto evita la necesidad de tener Tcl/Tk instalado para ejecutar los tests unitarios.
+    """
+    # Guardamos referencias originales para restaurar al finalizar el test
+    original_Tk = tk.Tk
+    original_Entry = tk.Entry
+    original_Button = tk.Button
+    original_Label = tk.Label
+
+    tk.Tk = DummyRoot
+    tk.Entry = DummyEntry
+    tk.Button = DummyButton
+    tk.Label = DummyLabel
+
+    try:
+        yield
+    finally:
+        # restaurar
+        tk.Tk = original_Tk
+        tk.Entry = original_Entry
+        tk.Button = original_Button
+        tk.Label = original_Label