[PATCH 1 of 2 evolve-ext] evolve: adding test case for calling split without -r argument

[Kostia Balytskyi]

# HG changeset patch
# User Kostia Balytskyi <ikostia at fb.com>
# Date 1454086569 28800
#      Fri Jan 29 08:56:09 2016 -0800
# Node ID 817cf1e8333856dd21b2886a61acef90e2151a7b
# Parent  983f2e4dbe5d4d97d6ca82f6679913d75c1f2577
evolve: adding test case for calling split without -r argument

Currently, if one runs `hg split .` or `hg split`, it will fail
with an exception. This happens becuase we only expect revision
args to be passed as --rev/-r ones and don't treat unnamed args
properly or add default values if no args are provided.

This test fails without the following commit and demonstrates
this bug.

diff --git a/tests/test-split.t b/tests/test-split.t
--- a/tests/test-split.t
+++ b/tests/test-split.t
@@ -335,4 +335,34 @@
   abort: cannot split commit: ced8fbcce3a7 not a head
   [255]
 
+Changing evolution level to createmarkers
+  $ echo "[experimental]" >> $HGRCPATH
+  $ echo "evolution=createmarkers" >> $HGRCPATH
 
+Running split without any revision
+  $ hg split << EOF
+  > q
+  > EOF
+  (leaving bookmark bookB)
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  adding _d
+  diff --git a/_d b/_d
+  new file mode 100644
+  examine changes to '_d'? [Ynesfdaq?] q
+  
+  abort: user quit
+  [255]
+
+Running split with tip revision, specified as unnamed argument
+  $ hg split . << EOF
+  > q
+  > EOF
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  adding _d
+  diff --git a/_d b/_d
+  new file mode 100644
+  examine changes to '_d'? [Ynesfdaq?] q
+  
+  abort: user quit
+  [255]
+