interpreter: replace mock keyword argument with unittest.mock

Python provides some nifty tools for mocking, without relying on
altering running code. We should use these to simplify the actual run
paths and move the complicated logic into tests.

3 files changed, 19 insertions, 12 deletions

diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index b736aea41..bee64aa94 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -266,7 +266,6 @@ class Interpreter(InterpreterBase, HoldableObject):
                 subdir: str = '',
                 subproject_dir: str = 'subprojects',
                 default_project_options: T.Optional[T.Dict[OptionKey, str]] = None,
-                mock: bool = False,
                 ast: T.Optional[mparser.CodeBlockNode] = None,
                 is_translated: bool = False,
                 relaxations: T.Optional[T.Set[InterpreterRuleRelaxation]] = None,
@@ -285,12 +284,11 @@ class Interpreter(InterpreterBase, HoldableObject):
         self.subproject_directory_name = subdir.split(os.path.sep)[-1]
         self.subproject_dir = subproject_dir
         self.relaxations = relaxations or set()
-        if not mock and ast is None:
+        if ast is None:
             self.load_root_meson_file()
-            self.sanity_check_ast()
-        elif ast is not None:
+        else:
             self.ast = ast
-            self.sanity_check_ast()
+        self.sanity_check_ast()
         self.builtin.update({'meson': MesonMain(self.build, self)})
         self.generators: T.List[build.Generator] = []
         self.processed_buildfiles: T.Set[str] = set()
@@ -319,8 +317,7 @@ class Interpreter(InterpreterBase, HoldableObject):
         build_filename = os.path.join(self.subdir, environment.build_filename)
         if not is_translated:
             self.build_def_files.add(build_filename)
-        if not mock:
-            self.parse_project()
+        self.parse_project()
         self._redetect_machines()
 
     def __getnewargs_ex__(self) -> T.Tuple[T.Tuple[object], T.Dict[str, object]]:
diff --git a/unittests/datatests.py b/unittests/datatests.py
index ae32a9491..4f9d52032 100644
--- a/unittests/datatests.py
+++ b/unittests/datatests.py
@@ -5,6 +5,7 @@ import re
 import unittest
 from itertools import chain
 from pathlib import Path
+from unittest import mock
 
 import mesonbuild.mlog
 import mesonbuild.depfile
@@ -208,7 +209,10 @@ class DataTests(unittest.TestCase):
             name = name.replace('_', '-')
             self.assertIn(name, html)
 
-    @unittest.mock.patch.dict(os.environ)
+    @mock.patch.dict(os.environ)
+    @mock.patch.object(Interpreter, 'load_root_meson_file', mock.Mock(return_value=None))
+    @mock.patch.object(Interpreter, 'sanity_check_ast', mock.Mock(return_value=None))
+    @mock.patch.object(Interpreter, 'parse_project', mock.Mock(return_value=None))
     def test_vim_syntax_highlighting(self):
         '''
         Ensure that vim syntax highlighting files were updated for new
@@ -217,13 +221,16 @@ class DataTests(unittest.TestCase):
         # Disable unit test specific syntax
         del os.environ['MESON_RUNNING_IN_PROJECT_TESTS']
         env = get_fake_env()
-        interp = Interpreter(FakeBuild(env), mock=True)
+        interp = Interpreter(FakeBuild(env))
         with open('data/syntax-highlighting/vim/syntax/meson.vim', encoding='utf-8') as f:
             res = re.search(r'syn keyword mesonBuiltin(\s+\\\s\w+)+', f.read(), re.MULTILINE)
             defined = set([a.strip() for a in res.group().split('\\')][1:])
             self.assertEqual(defined, set(chain(interp.funcs.keys(), interp.builtin.keys())))
 
-    @unittest.mock.patch.dict(os.environ)
+    @mock.patch.dict(os.environ)
+    @mock.patch.object(Interpreter, 'load_root_meson_file', mock.Mock(return_value=None))
+    @mock.patch.object(Interpreter, 'sanity_check_ast', mock.Mock(return_value=None))
+    @mock.patch.object(Interpreter, 'parse_project', mock.Mock(return_value=None))
     def test_all_functions_defined_in_ast_interpreter(self):
         '''
         Ensure that the all functions defined in the Interpreter are also defined
@@ -232,6 +239,6 @@ class DataTests(unittest.TestCase):
         # Disable unit test specific syntax
         del os.environ['MESON_RUNNING_IN_PROJECT_TESTS']
         env = get_fake_env()
-        interp = Interpreter(FakeBuild(env), mock=True)
+        interp = Interpreter(FakeBuild(env))
         astint = AstInterpreter('.', '', '')
         self.assertEqual(set(interp.funcs.keys()), set(astint.funcs.keys()))
diff --git a/unittests/internaltests.py b/unittests/internaltests.py
index 945faa18b..fd843c88c 100644
--- a/unittests/internaltests.py
+++ b/unittests/internaltests.py
@@ -1662,13 +1662,16 @@ class InternalTests(unittest.TestCase):
                     actual = mesonbuild.environment.detect_cpu({})
                     self.assertEqual(actual, expected)
 
+    @mock.patch('mesonbuild.interpreter.Interpreter.load_root_meson_file', mock.Mock(return_value=None))
+    @mock.patch('mesonbuild.interpreter.Interpreter.sanity_check_ast', mock.Mock(return_value=None))
+    @mock.patch('mesonbuild.interpreter.Interpreter.parse_project', mock.Mock(return_value=None))
     def test_interpreter_unpicklable(self) -> None:
         build = mock.Mock()
         build.environment = mock.Mock()
         build.environment.get_source_dir = mock.Mock(return_value='')
         with mock.patch('mesonbuild.interpreter.Interpreter._redetect_machines', mock.Mock()), \
                 self.assertRaises(mesonbuild.mesonlib.MesonBugException):
-            i = mesonbuild.interpreter.Interpreter(build, mock=True)
+            i = mesonbuild.interpreter.Interpreter(build)
             pickle.dumps(i)
 
     def test_major_versions_differ(self) -> None: