tests: add test for add of explicit path in subrepo

Add test coverage for the existing behavior where adds of explicit paths in
subrepos are silently ignored.  This is in preparation for changing the
behavior of the add command to have better support for subrepos.

tests/test-subrepo.t

@@ -883,3 +883,126 b' Test that removing .hgsub removes .hgsub'
   rm2
   
   
+Test behavior of add for explicit path in subrepo:
+  $ cd ..
+  $ hg init addtests
+  $ cd addtests
+  $ echo s = s > .hgsub
+  $ hg add .hgsub
+  $ hg init s
+  $ hg ci -m0
+  committing subrepository s
+Adding with an explicit path in a subrepo currently fails silently
+  $ echo c1 > f1
+  $ echo c2 > s/f2
+  $ hg st -S
+  ? f1
+  ? s/f2
+  $ hg add s/f2
+  $ hg st -S
+  ? f1
+  ? s/f2
+  $ hg ci -R s -Am0
+  adding f2
+  $ hg ci -Am1
+  adding f1
+  committing subrepository s
+Adding with an explicit path in a subrepo with -S adds the file
+  $ echo c3 > f3
+  $ echo c4 > s/f4
+  $ hg st -S
+  ? f3
+  ? s/f4
+  $ hg add -S s/f4
+  $ hg st -S
+  A s/f4
+  ? f3
+  $ hg ci -R s -m1
+  $ hg ci -Ama2
+  adding f3
+  committing subrepository s
+Adding without a path or pattern silently ignores subrepos
+  $ echo c5 > f5
+  $ echo c6 > s/f6
+  $ echo c7 > s/f7
+  $ hg st -S
+  ? f5
+  ? s/f6
+  ? s/f7
+  $ hg add
+  adding f5
+  $ hg st -S
+  A f5
+  ? s/f6
+  ? s/f7
+  $ hg ci -R s -Am2
+  adding f6
+  adding f7
+  $ hg ci -m3
+  committing subrepository s
+Adding without a path or pattern with -S also adds files in subrepos
+  $ echo c8 > f8
+  $ echo c9 > s/f9
+  $ echo c10 > s/f10
+  $ hg st -S
+  ? f8
+  ? s/f10
+  ? s/f9
+  $ hg add -S
+  adding f8
+  adding s/f10
+  adding s/f9
+  $ hg st -S
+  A f8
+  A s/f10
+  A s/f9
+  $ hg ci -R s -m3
+  $ hg ci -m4
+  committing subrepository s
+Adding with a pattern silently ignores subrepos
+  $ echo c11 > fm11
+  $ echo c12 > fn12
+  $ echo c13 > s/fm13
+  $ echo c14 > s/fn14
+  $ hg st -S
+  ? fm11
+  ? fn12
+  ? s/fm13
+  ? s/fn14
+  $ hg add 'glob:**fm*'
+  adding fm11
+  $ hg st -S
+  A fm11
+  ? fn12
+  ? s/fm13
+  ? s/fn14
+  $ hg ci -R s -Am4
+  adding fm13
+  adding fn14
+  $ hg ci -Am5
+  adding fn12
+  committing subrepository s
+Adding with a pattern with -S also adds matches in subrepos
+  $ echo c15 > fm15
+  $ echo c16 > fn16
+  $ echo c17 > s/fm17
+  $ echo c18 > s/fn18
+  $ hg st -S
+  ? fm15
+  ? fn16
+  ? s/fm17
+  ? s/fn18
+  $ hg add -S 'glob:**fm*'
+  adding fm15
+  adding s/fm17
+  $ hg st -S
+  A fm15
+  A s/fm17
+  ? fn16
+  ? s/fn18
+  $ hg ci -R s -Am5
+  adding fn18
+  $ hg ci -Am6
+  adding fn16
+  committing subrepository s
+  $ cd ..