Implement basic version of local shell

Also added two simple reporters that can be used by the shell to report command execution details.

Signed-off-by: Vladimir Domnich <v.domnich@yadro.com>

tests/test_local_shell_non_interactive.py

@@ -0,0 +1,46 @@
+from unittest import TestCase
+
+from shell.interfaces import CommandOptions
+from shell.local_shell import LocalShell
+from tests.helpers import format_error_details
+
+
+class TestLocalShellNonInteractive(TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.shell = LocalShell()
+
+    def test_successful_command(self):
+        script = "print('test')"
+
+        result = self.shell.exec(f"python -c \"{script}\"")
+
+        self.assertEqual(0, result.return_code)
+        self.assertEqual("test", result.stdout.strip())
+        self.assertEqual("", result.stderr)
+
+    def test_failed_command_with_check(self):
+        script = "invalid script"
+
+        with self.assertRaises(RuntimeError) as exc:
+            self.shell.exec(f"python -c \"{script}\"")
+
+        error = format_error_details(exc.exception)
+        self.assertIn("Error", error)
+        self.assertIn("return code: 1", error)
+
+    def test_failed_command_without_check(self):
+        script = "invalid script"
+
+        result = self.shell.exec(f"python -c \"{script}\"", CommandOptions(check=False))
+
+        self.assertEqual(1, result.return_code)
+        self.assertIn("Error", result.stdout)
+
+    def test_non_existing_binary(self):
+        with self.assertRaises(RuntimeError) as exc:
+            self.shell.exec(f"not-a-command")
+
+        error = format_error_details(exc.exception)
+        self.assertIn("Error", error)
+        self.assertIn("return code: 127", error)