test-imerge: test resolve subcommand

tests/test-imerge

@@ -33,6 +33,12 b' hg -v imerge st'
 echo % next
 hg imerge next
 
+echo % resolve and unresolve
+hg imerge resolve foo
+hg -v imerge st
+hg imerge unresolve foo
+hg -v imerge st
+
 echo % merge next
 hg --traceback imerge
 

tests/test-imerge.out

@@ -15,6 +15,12 b' merging e6da46716401 and 30d266f502e7'
 U foo (foo2)
 % next
 foo
+% resolve and unresolve
+merging e6da46716401 and 30d266f502e7
+R foo (foo2)
+all conflicts resolved
+merging e6da46716401 and 30d266f502e7
+U foo (foo2)
 % merge next
 merging foo and foo2
 all conflicts resolved