wvtest: chdir to start dir before extracting stack

It looks like traceback may not be able to find the source text if the
current directory has been changed from the original.

Signed-off-by: Rob Browning <rlb@defaultvalue.org>
Tested-by: Rob Browning <rlb@defaultvalue.org>

diff --git a/wvtest.py b/wvtest.py
index 561cc8794ba8e93fc43be65fbd5a50ba53922bb0..61245b29bc4fc976634624b88f1d48e7f409fa37 100755 (executable)
--- a/wvtest.py
+++ b/wvtest.py
@@ -18,6 +18,8 @@ import re
 import sys
 import traceback
 
+_start_dir = os.getcwd()
+
 # NOTE
 # Why do we do we need the "!= main" check?  Because if you run
 # wvtest.py as a main program and it imports your test files, then
@@ -63,8 +65,18 @@ if __name__ != '__main__':   # we're imported as a module
         sys.stdout.flush()
 
 
+    def _caller_stack():
+        # Without the chdir, the source text lookup may fail
+        orig = os.getcwd()
+        os.chdir(_start_dir)
+        try:
+            return traceback.extract_stack()[-4]
+        finally:
+            os.chdir(orig)
+
+
     def _check(cond, msg = 'unknown', tb = None):
-        if tb == None: tb = traceback.extract_stack()[-3]
+        if tb == None: tb = _caller_stack()
         if cond:
             _result(msg, tb, 'ok')
         else:
@@ -73,14 +85,12 @@ if __name__ != '__main__':   # we're imported as a module
 
     _code_rx = re.compile(r'^\w+\((.*)\)(\s*#.*)?$')
     def _code():
-        (filename, line, func, text) = traceback.extract_stack()[-3]
+        text = _caller_stack()[3]
         return _code_rx.sub(r'\1', text)
 
-
-
     def WVMSG(message):
         ''' Issues a notification. '''
-        return _result(message, traceback.extract_stack()[-3], 'ok')
+        return _result(message, _caller_stack(), 'ok')
 
     def WVPASS(cond = True):
         ''' Counts a test failure unless cond is true. '''