improve PYTEST_DEBUG tracing output

by putingextra data on a new lines
with additional indent

CHANGELOG

@@ -13,6 +13,9 @@ Changes between 2.3.4 and 2.3.5dev
 - allow to specify prefixes starting with "_" when 
   customizing python_functions test discovery. (thanks Graham Horler)
 
+- improve PYTEST_DEBUG tracing output by puting
+  extra data on a new lines with additional indent
+
 Changes between 2.3.3 and 2.3.4
 -----------------------------------
 

_pytest/core.py

@@ -24,12 +24,28 @@ class TagTracer:
     def get(self, name):
         return TagTracerSub(self, (name,))
 
+    def format_message(self, tags, args):
+        if isinstance(args[-1], dict):
+            extra = args[-1]
+            args = args[:-1]
+        else:
+            extra = {}
+
+        content = " ".join(map(str, args))
+        indent = "  " * self.indent
+        
+        lines = [
+            "%s%s [%s]\n" %(indent, content, ":".join(tags))
+        ]
+
+        for name, value in extra.items():
+            lines.append("%s    %s: %s\n" % (indent, name, value))
+        return lines
+
     def processmessage(self, tags, args):
-        if self.writer is not None:
+        if self.writer is not None and args:
-            if args:
+            lines = self.format_message(tags, args)
-                indent = "  " * self.indent
+            self.writer(''.join(lines))
-                content = " ".join(map(str, args))
-                self.writer("%s%s [%s]\n" %(indent, content, ":".join(tags)))
         try:
             self._tag2proc[tags](tags, args)
         except KeyError:

testing/test_core.py

@@ -612,6 +612,19 @@ class TestTracer:
         assert names == ['hello', '  line1', '  line2',
                      '    line3', '    line4', '  line5', 'last']
 
+    def test_readable_output_dictargs(self):
+        from _pytest.core import TagTracer
+        rootlogger = TagTracer()
+
+        out = rootlogger.format_message(['test'], [1])
+        assert out == ['1 [test]\n']
+
+        out2= rootlogger.format_message(['test'], ['test', {'a':1}])
+        assert out2 ==[
+            'test [test]\n',
+            '    a: 1\n'
+        ]
+
     def test_setprocessor(self):
         from _pytest.core import TagTracer
         rootlogger = TagTracer()