test: Separate out the exception handling

The tests currently catch a very broad Exception in each case. This is
thrown even in the event of a coding error.

We want to handle exceptions differently depending on their severity,
so that we can avoid hour-long delays waiting for a board that is
clearly broken.

As a first step, create some new exception types, separating out those
which are simply an unexpected result from executed a command, from
those which indicate some kind of hardware failure.

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

test/py/u_boot_console_base.py

@@ -14,6 +14,7 @@ import pytest
 import re
 import sys
 import u_boot_spawn
+from u_boot_spawn import BootFail, Timeout, Unexpected
 
 # Regexes for text we expect U-Boot to send to the console.
 pattern_u_boot_spl_signon = re.compile('(U-Boot SPL \\d{4}\\.\\d{2}[^\r\n]*\\))')
@@ -189,13 +190,13 @@ class ConsoleBase(object):
                     m = self.p.expect([pattern_u_boot_spl_signon] +
                                       self.bad_patterns)
                     if m != 0:
-                        raise Exception('Bad pattern found on SPL console: ' +
+                        raise BootFail('Bad pattern found on SPL console: ' +
                                         self.bad_pattern_ids[m - 1])
                     env_spl_banner_times -= 1
 
                 m = self.p.expect([pattern_u_boot_main_signon] + self.bad_patterns)
                 if m != 0:
-                    raise Exception('Bad pattern found on console: ' +
+                    raise BootFail('Bad pattern found on console: ' +
                                     self.bad_pattern_ids[m - 1])
             self.u_boot_version_string = self.p.after
             while True:
@@ -206,13 +207,9 @@ class ConsoleBase(object):
                 if m == 1:
                     self.p.send(' ')
                     continue
-                raise Exception('Bad pattern found on console: ' +
+                raise BootFail('Bad pattern found on console: ' +
                                 self.bad_pattern_ids[m - 2])
 
-        except Exception as ex:
-            self.log.error(str(ex))
-            self.cleanup_spawn()
-            raise
         finally:
             self.log.timestamp()
 
@@ -278,7 +275,7 @@ class ConsoleBase(object):
                 m = self.p.expect([chunk] + self.bad_patterns)
                 if m != 0:
                     self.at_prompt = False
-                    raise Exception('Bad pattern found on console: ' +
+                    raise BootFail('Bad pattern found on console: ' +
                                     self.bad_pattern_ids[m - 1])
             if not wait_for_prompt:
                 return
@@ -288,14 +285,18 @@ class ConsoleBase(object):
                 m = self.p.expect([self.prompt_compiled] + self.bad_patterns)
                 if m != 0:
                     self.at_prompt = False
-                    raise Exception('Bad pattern found on console: ' +
+                    raise BootFail('Missing prompt on console: ' +
                                     self.bad_pattern_ids[m - 1])
             self.at_prompt = True
             self.at_prompt_logevt = self.logstream.logfile.cur_evt
             # Only strip \r\n; space/TAB might be significant if testing
             # indentation.
             return self.p.before.strip('\r\n')
-        except Exception as ex:
+        except Timeout as exc:
+            self.log.error(str(exc))
+            self.cleanup_spawn()
+            raise
+        except BootFail as ex:
             self.log.error(str(ex))
             self.cleanup_spawn()
             raise
@@ -354,8 +355,9 @@ class ConsoleBase(object):
             text = re.escape(text)
         m = self.p.expect([text] + self.bad_patterns)
         if m != 0:
-            raise Exception('Bad pattern found on console: ' +
+            raise Unexpected(
-                            self.bad_pattern_ids[m - 1])
+                "Unexpected pattern found on console (exp '{text}': " +
+                self.bad_pattern_ids[m - 1])
 
     def drain_console(self):
         """Read from and log the U-Boot console for a short time.

test/py/u_boot_spawn.py

@@ -16,6 +16,17 @@ import traceback
 class Timeout(Exception):
     """An exception sub-class that indicates that a timeout occurred."""
 
+class BootFail(Exception):
+    """An exception sub-class that indicates that a boot failure occurred.
+
+    This is used when a bad pattern is seen when waiting for the boot prompt.
+    It is regarded as fatal, to avoid trying to boot the again and again to no
+    avail.
+    """
+
+class Unexpected(Exception):
+    """An exception sub-class that indicates that unexpected test was seen."""
+
 class Spawn:
     """Represents the stdio of a freshly created sub-process. Commands may be
     sent to the process, and responses waited for.