fix(tools): idf_tools.py tests should keep the original constraint file

tools/test_idf_tools/test_idf_tools_python_env.py

@@ -231,11 +231,37 @@ class TestCustomPythonPathInstall(BasePythonInstall):
 
 
 class TestCheckPythonDependencies(BasePythonInstall):
+
+    """
+    The constraint file name is available as the constraint_file attribute. The content of the file is changed by these
+    tests. The backup_constraint_file is a temporary file with the content of the original constraint file. This is
+    kept in order to restore the original content of the constraint file. Keeping the original constraint file is
+    important for consequent tests which should not download a new one especially when the test was run with a custom
+    constraint file different from the one on dl.espressif.com.
+    """
+    constraint_file: str
+    backup_constraint_file: str
+
+    @classmethod
+    def setUpClass(cls):  # type: () -> None
+        cls.constraint_file = idf_tools.get_constraints(idf_tools.get_idf_version(), online=False)
+        with tempfile.NamedTemporaryFile() as f:
+            cls.backup_constraint_file = f.name
+        shutil.copyfile(cls.constraint_file, cls.backup_constraint_file)
+
+    @classmethod
+    def tearDownClass(cls):  # type: () -> None
+        try:
+            os.remove(cls.backup_constraint_file)
+        except OSError:
+            pass
+
     def setUp(self):  # type: () -> None
         if os.path.isdir(PYTHON_DIR):
             shutil.rmtree(PYTHON_DIR)
 
     def tearDown(self):  # type: () -> None
+        shutil.copyfile(self.backup_constraint_file, self.constraint_file)
         if os.path.isdir(PYTHON_DIR):
             shutil.rmtree(PYTHON_DIR)
 
@@ -256,14 +282,10 @@ class TestCheckPythonDependencies(BasePythonInstall):
         # are also present in the freeze list.
         con_list = [r.replace('==', '>') for r in freeze_output.splitlines() if r.split('==')[0] in req_list]
 
-        con_fn = idf_tools.get_constraints(idf_tools.get_idf_version(), online=False)
-        # delete modified constraints file after this test is finished
-        self.addCleanup(os.remove, con_fn)
-
         # Write the created constraints list into existing constraints file.
         # It will not be overwritten by subsequent idf_tools.py run, because
         # there is timestamp check.
-        with open(con_fn, 'w') as fd:
+        with open(self.constraint_file, 'w') as fd:
             fd.write(os.linesep.join(con_list))
 
         # Test that check_python_dependencies reports that requirements are not satisfied for
@@ -283,12 +305,8 @@ class TestCheckPythonDependencies(BasePythonInstall):
         foo_pkg = self.dump_foopackage()
         self.run_in_venv(['-m', 'pip', 'install', foo_pkg])
 
-        con_fn = idf_tools.get_constraints(idf_tools.get_idf_version(), online=False)
-        # delete modified constraints file after this test is finished
-        self.addCleanup(os.remove, con_fn)
-
         # append foopackage constraint to the existing constraints file
-        with open(con_fn, 'a') as fd:
+        with open(self.constraint_file, 'a') as fd:
             fd.write('foopackage>0.99')
 
         # check-python-dependencies should not complain about dummy_package
@@ -305,12 +323,8 @@ class TestCheckPythonDependencies(BasePythonInstall):
         foo_pkg = self.dump_foopackage_dev()
         self.run_in_venv(['-m', 'pip', 'install', foo_pkg])
 
-        con_fn = idf_tools.get_constraints(idf_tools.get_idf_version(), online=False)
-        # delete modified constraints file after this test is finished
-        self.addCleanup(os.remove, con_fn)
-
         # append foopackage constraint to the existing constraints file
-        with open(con_fn, 'r+') as fd:
+        with open(self.constraint_file, 'r+') as fd:
             con_lines = fd.readlines()
             fd.write('foopackage~=0.98')
 
@@ -318,7 +332,7 @@ class TestCheckPythonDependencies(BasePythonInstall):
         self.assertIn(REQ_SATISFIED, output)
 
         # append foopackage dev version constraint to the existing constraints file
-        with open(con_fn, 'r+') as fd:
+        with open(self.constraint_file, 'r+') as fd:
             fd.writelines(con_lines + ['foopackage==0.99.dev0'])
 
         output = self.run_idf_tools(['check-python-dependencies'])