Avoid overriding branch references

In case the repo is currently at a different branch than the one
to be changed to, git reset would modify the current branch ref,
so future usages of that branch don't work anymore
(they all point to the same commit ref).

Author: adangel

lib/pmdtester/builders/project_builder.rb

@@ -89,7 +89,7 @@ def run_as_script(path, command)
     def execute_reset_cmd(type, tag)
       case type
       when 'git'
-        reset_cmd = "git reset --hard #{tag}"
+        reset_cmd = "git checkout #{tag}; git reset --hard #{tag}"
       when 'hg'
         reset_cmd = "hg up #{tag}"
       end

test/test_project_builder.rb

@@ -12,9 +12,9 @@ def setup
 
   def test_clone
     expect_clone('checkstyle', 'git', 'https://github.com/checkstyle/checkstyle',
-                 'git reset --hard master')
+                 'git checkout master; git reset --hard master')
     expect_clone('spring-framework', 'git', 'https://github.com/spring-projects/spring-framework',
-                 'git reset --hard v5.0.6.RELEASE')
+                 'git checkout v5.0.6.RELEASE; git reset --hard v5.0.6.RELEASE')
 
     project_builder = PmdTester::ProjectBuilder.new(@projects)
     project_builder.clone_projects