--- a/tests/test-config.t	Wed Aug 20 22:52:56 2014 -0700
+++ b/tests/test-config.t	Sun Mar 16 17:31:31 2014 +0200
@@ -19,6 +19,25 @@
   hg: parse error at $TESTTMP/.hg/hgrc:1: =nokeyvalue
   [255]
 
+Test hint about invalid syntax from leading white space
+
+  $ cat > .hg/hgrc << EOF
+  >  key=value
+  > EOF
+  $ hg showconfig
+  hg: parse error at $TESTTMP/.hg/hgrc:1:  key=value
+  unexpected leading whitespace
+  [255]
+
+  $ cat > .hg/hgrc << EOF
+  >  [section]
+  > key=value
+  > EOF
+  $ hg showconfig
+  hg: parse error at $TESTTMP/.hg/hgrc:1:  [section]
+  unexpected leading whitespace
+  [255]
+
 Reset hgrc
 
   $ echo > .hg/hgrc