feat: make it easier to debug generated Python test programs

The generated test program now has --log and --save-on-failure
options, and automatically logs every scenario, step, and change to
context.

1 files changed, 60 insertions, 4 deletions

diff --git a/templates/python/template.py b/templates/python/template.py
index 87ced78..62b1fc9 100644
--- a/templates/python/template.py
+++ b/templates/python/template.py
@@ -7,12 +7,14 @@
 #############################################################################
 # Helper code generated by Subplot.
 
+import argparse
 import base64
 import logging
 import os
 import random
 import shutil
 import sys
+import tarfile
 import tempfile
 
 # Store context between steps.
@@ -31,6 +33,7 @@ class Context:
         return self._vars[key]
 
     def __setitem__(self, key, value):
+        logging.info('Context: {}={!r}'.format(key, value))
         self._vars[key] = value
 
 # Decode a base64 encoded string. Result is binary or unicode string.
@@ -85,6 +88,7 @@ os.chdir(_datadir)
 def scenario_{{ loop.index }}():
     title = decode_str('{{ scenario.title | base64 }}')
     print('scenario: {}'.format(title))
+    logging.info("Scenario: {}".format(title))
     _scendir = tempfile.mkdtemp(dir=_datadir)
     os.chdir(_scendir)
     ctx = Context()
@@ -92,6 +96,7 @@ def scenario_{{ loop.index }}():
     # Step: {{ step.text }}
     step = decode_str('{{ step.text | base64 }}')
     print('  step: {{ step.kind | lower }} {}'.format(step))
+    logging.info('  step: {{ step.kind | lower }} {}'.format(step))
     args = {}
     {% for part in step.parts %}{% if part.CapturedText is defined -%}
     name = decode_str('{{ part.CapturedText.name | base64 }}')
@@ -110,20 +115,70 @@ _scenarios = {
 }
 
 
+def parse_command_line():
+    p = argparse.ArgumentParser()
+    p.add_argument("--log")
+    p.add_argument("--save-on-failure")
+    p.add_argument("patterns", nargs="*")
+    return p.parse_args()
+
+
+def setup_logging(args):
+    if args.log:
+        fmt = "%(asctime)s %(levelname)s %(message)s"
+        datefmt = "%Y-%m-%d %H:%M:%S"
+        formatter = logging.Formatter(fmt, datefmt)
+
+        filename = os.path.abspath(os.path.join(srcdir, args.log))
+        handler = logging.FileHandler(filename)
+        handler.setFormatter(formatter)
+    else:
+        handler = logging.NullHandler()
+
+    logger = logging.getLogger()
+    logger.addHandler(handler)
+    logger.setLevel(logging.DEBUG)
+
+
+def save_directory(dirname, tarname):
+    print('tarname', tarname)
+    logging.info("Saving {} to {}".format(dirname, tarname))
+    tar = tarfile.open(tarname, "w")
+    tar.add(dirname, arcname="datadir")
+    tar.close()
+
+
 def main():
-    if len(sys.argv) == 1:
+    args = parse_command_line()
+    setup_logging(args)
+    logging.info("Test program starts")
+
+    logging.info("patterns: {}".format(args.patterns))
+    if len(args.patterns) == 0:
+        logging.info("Executing all scenarios")
         funcs = list(_scenarios.values())
         random.shuffle(funcs)
     else:
-        patterns = [arg.lower() for arg in sys.argv[1:]]
+        logging.info("Executing requested scenarios only: {}".format(args.patterns))
+        patterns = [arg.lower() for arg in args.patterns]
         funcs = [
             func
             for title, func in _scenarios.items()
             if any(pattern in title.lower() for pattern in patterns)
         ]
 
-    for func in funcs:
-        func()
+    try:
+        for func in funcs:
+            func()
+    except Exception as e:
+        logging.error(str(e), exc_info=True)
+        if args.save_on_failure:
+            print(args.save_on_failure)
+            filename = os.path.abspath(os.path.join(srcdir, args.save_on_failure))
+            print(filename)
+            save_directory(_datadir, filename)
+        raise
+
 
 main()
 
@@ -132,3 +187,4 @@ main()
 
 shutil.rmtree(_datadir)
 print('OK, all scenarios finished successfully')
+logging.info("OK, all scenarios finished successfully")