Make reports directory build work correctly

rakefile

@@ -38,6 +38,10 @@ def django_admin(system, env, command, *args)
     return "#{django_admin} #{command} --settings=#{system}.envs.#{env} --pythonpath=. #{args.join(' ')}"
 end
 
+def report_dir_path(dir)
+    return File.join(REPORT_DIR, dir.to_s)
+end
+
 task :default => [:test, :pep8, :pylint]
 
 directory REPORT_DIR
@@ -58,7 +62,7 @@ task :clean_test_files do
 end
 
 [:lms, :cms, :common].each do |system|
-    report_dir = File.join(REPORT_DIR, system.to_s)
+    report_dir = report_dir_path(system)
     directory report_dir
 
     desc "Run pep8 on all #{system} code"
@@ -107,8 +111,7 @@ end
 TEST_TASK_DIRS = []
 
 [:lms, :cms].each do |system|
-    report_dir = File.join(REPORT_DIR, system.to_s)
-    directory report_dir
+    report_dir = report_dir_path(system)
 
     # Per System tasks
     desc "Run all django tests on our djangoapps for the #{system}"
@@ -154,8 +157,7 @@ end
 Dir["common/lib/*"].select{|lib| File.directory?(lib)}.each do |lib|
     task_name = "test_#{lib}"
 
-    report_dir = File.join(REPORT_DIR, task_name.gsub('/', '_'))
-    directory report_dir
+    report_dir = report_dir_path(lib)
 
     desc "Run tests for common lib #{lib}"
     task task_name => report_dir do
@@ -174,6 +176,14 @@ Dir["common/lib/*"].select{|lib| File.directory?(lib)}.each do |lib|
 
 end
 
+task :report_dirs
+
+TEST_TASK_DIRS.each do |dir|
+    report_dir = report_dir_path(dir)
+    directory report_dir
+    task :report_dirs => [REPORT_DIR, report_dir]
+end
+
 task :test do
     TEST_TASK_DIRS.each do |dir|
         Rake::Task["test_#{dir}"].invoke(false)
@@ -186,14 +196,14 @@ end
 
 namespace :coverage do
     desc "Build the html coverage reports"
-    task :html do
+    task :html => :report_dirs do
         TEST_TASK_DIRS.each do |dir|
             sh("coverage html --rcfile=#{dir}/.coveragerc")
         end
     end
 
     desc "Build the xml coverage reports"
-    task :xml do
+    task :xml => :report_dirs do
         TEST_TASK_DIRS.each do |dir|
             # Why doesn't the rcfile control the xml output file properly??
             sh("coverage xml -o reports/#{dir}/coverage.xml --rcfile=#{dir}/.coveragerc")