Add ability to specify target branch to test

This is now only initial implementation. There should be also
specification of board and more but that is going to be added later on
once we are able to run tests on more than one board.

imgs/boot/bin/prepare_turris_image

@@ -2,15 +2,11 @@
 set -e
 TFTP_ROOT="/var/tftpboot"
 
-# TODO use this
-BOARD="$1"
-MODE="$2"
-TARGET="$3"
-# TODO
+branch="${1:-hbk}"
 
 # Get appropriate medkit
 wait4network
-wget "https://repo.turris.cz/hbk/medkit/omnia-medkit-latest.tar.gz" -O medkit.tar.gz
+wget "https://repo.turris.cz/$branch/medkit/omnia-medkit-latest.tar.gz" -O medkit.tar.gz
 
 # Repack as CPIO
 mkdir root

tests/conftest.py

-import pytest
 import os
 import time
 import random
 import string
 import configparser
+import pytest
 import nsfarm.board
 import nsfarm.cli
 import nsfarm.lxd
@@ -21,6 +21,12 @@ def pytest_addoption(parser):
         help="Path to configuration file with additional targets.",
         metavar="PATH",
     )
+    parser.addoption(
+        "-B", "--branch",
+        default="hbk",
+        help="Run tests for specified Turris OS BRANCH.",
+        metavar="BRANCH",
+    )
 
 
 def pytest_configure(config):
@@ -36,6 +42,8 @@ def pytest_configure(config):
         if target not in targets:
             raise Exception(f"No configuration for target: {target}")
         setattr(config, "target_config", targets[target])
+    # Set target branch
+    setattr(config, "target_branch", config.getoption("-B"))
 
 
 def pytest_runtest_setup(item):
@@ -85,7 +93,7 @@ def fixture_board_serial(request, board, wan):
     Provides instance of nsfarm.cli.Shell()
     """
     request.addfinalizer(lambda: board.reset(True))
-    return board.bootup(wan)
+    return board.bootup(wan, request.config.target_branch)
 
 
 @pytest.fixture(name="board_root_password", scope="session")