test: Detect dead connections

When the connection to a board dies, assume it is dead forever until
some user action is taken. Skip all remaining tests. This avoids CI
runs taking an hour, with hundreds of 30-second timeouts all to no
avail.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/py/conftest.py

@@ -24,6 +24,7 @@ import pytest
 import re
 from _pytest.runner import runtestprotocol
 import sys
+from u_boot_spawn import BootFail, Timeout, Unexpected, handle_exception
 
 # Globals: The HTML log file, and the connection to the U-Boot console.
 log = None
@@ -254,6 +255,7 @@ def pytest_configure(config):
     ubconfig.board_identity = board_identity
     ubconfig.gdbserver = gdbserver
     ubconfig.dtb = build_dir + '/arch/sandbox/dts/test.dtb'
+    ubconfig.connection_ok = True
 
     env_vars = (
         'board_type',
@@ -420,8 +422,21 @@ def u_boot_console(request):
     Returns:
         The fixture value.
     """
-
-    console.ensure_spawned()
+    if not ubconfig.connection_ok:
+        pytest.skip('Cannot get target connection')
+        return None
+    try:
+        console.ensure_spawned()
+    except OSError as err:
+        handle_exception(ubconfig, console, log, err, 'Lab failure', True)
+    except Timeout as err:
+        handle_exception(ubconfig, console, log, err, 'Lab timeout', True)
+    except BootFail as err:
+        handle_exception(ubconfig, console, log, err, 'Boot fail', True,
+                         console.get_spawn_output())
+    except Unexpected:
+        handle_exception(ubconfig, console, log, err, 'Unexpected test output',
+                         False)
     return console
 
 anchors = {}