scm: subversion: refactor getting svn version and add lib test (#4273).

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@4825 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/scm/adapters/subversion_adapter.rb

@@ -38,19 +38,21 @@ module Redmine
           def client_version
             @@client_version ||= (svn_binary_version || [])
           end
+
+          def client_available
+            !client_version.empty?
+          end
 
           def svn_binary_version
-            cmd = "#{sq_bin} --version"
-            version = nil
-            shellout(cmd) do |io|
-              # Read svn version in first returned line
-              if m = io.read.to_s.match(%r{\A(.*?)((\d+\.)+\d+)})
-                version = m[2].scan(%r{\d+}).collect(&:to_i)
-              end
-            end
-            return nil if $? && $?.exitstatus != 0
-            version
+            scm_version = scm_version_from_command_line
+            if m = scm_version.match(%r{\A(.*?)((\d+\.)+\d+)})
+              m[2].scan(%r{\d+}).collect(&:to_i)
+            end
           end
+
+          def scm_version_from_command_line
+            shellout("#{sq_bin} --version") { |io| io.read }.to_s
+          end
         end
 
         # Get info about the svn repository