A way to artificially crash coverage, for testing.

2 files changed, 8 insertions, 1 deletions

diff --git a/coverage/config.py b/coverage/config.py
index 6372f4c0..452d320e 100644
--- a/coverage/config.py
+++ b/coverage/config.py
@@ -195,6 +195,7 @@ class CoverageConfig(object):
         self.run_omit = None
         self.source = None
         self.timid = False
+        self._crash = None
 
         # Defaults for [report]
         self.exclude_list = DEFAULT_EXCLUDE[:]
@@ -359,6 +360,7 @@ class CoverageConfig(object):
         ('run_omit', 'run:omit', 'list'),
         ('source', 'run:source', 'list'),
         ('timid', 'run:timid', 'boolean'),
+        ('_crash', 'run:_crash'),
 
         # [report]
         ('exclude_list', 'report:exclude_lines', 'regexlist'),
diff --git a/coverage/control.py b/coverage/control.py
index fdd1556e..6e59078c 100644
--- a/coverage/control.py
+++ b/coverage/control.py
@@ -18,7 +18,7 @@ from coverage.collector import Collector, CTracer
 from coverage.config import read_coverage_config
 from coverage.context import should_start_context_test_function, combine_context_switchers
 from coverage.data import CoverageData, combine_parallel_data
-from coverage.debug import DebugControl, write_formatted_info
+from coverage.debug import DebugControl, short_stack, write_formatted_info
 from coverage.disposition import disposition_debug_msg
 from coverage.files import PathAliases, abs_file, relative_filename, set_relative_directory
 from coverage.html import HtmlReporter
@@ -280,6 +280,11 @@ class Coverage(object):
             self._wrote_debug = True
             self._write_startup_debug()
 
+        # '[run] _crash' will raise an exception if the value is close by in
+        # the call stack, for testing error handling.
+        if self.config._crash and self.config._crash in short_stack(limit=4):
+            raise Exception("Crashing because called by {}".format(self.config._crash))
+
     def _write_startup_debug(self):
         """Write out debug info at startup if needed."""
         wrote_any = False