test-merge-default and check-code.py: No "export x=x" in sh

contrib/check-code.py

@@ -52,6 +52,7 b' testpats = ['
     (r'/bin/', "don't use explicit paths for tools"),
     (r'\$PWD', "don't use $PWD, use `pwd`"),
     (r'[^\n]\Z', "no trailing newline"),
+    (r'export.*=', "don't export and assign at once"),
 ]
 
 testfilters = [

tests/test-merge-default

@@ -24,7 +24,7 b' hg merge'
 
 hg up
 echo % should fail because \> 2 heads
-export HGMERGE=internal:other
+HGMERGE=internal:other; export HGMERGE
 hg merge
 
 echo % should succeed