covermode should be atomic if there are goroutines

Signed-off-by: Ying Li <ying.li@docker.com>

buildscripts/covertest.py

@@ -32,7 +32,7 @@ def get_coverprofile_filename(pkg, buildtags):
         buildtags = "." + buildtags.replace(' ', '.')
     return pkg.replace('/', '-').replace(' ', '_') + buildtags + ".coverage.txt"
 
-def run_test_with_coverage(buildtags="", coverdir=".cover", pkgs=None, opts="", covermode="count"):
+def run_test_with_coverage(buildtags="", coverdir=".cover", pkgs=None, opts="", covermode="atomic"):
     """
     Run go test with coverage over the the given packages, with the following options
     """
@@ -51,6 +51,7 @@ def run_test_with_coverage(buildtags="", coverdir=".cover", pkgs=None, opts="",
 
     for pkg in pkgs:
         cmd = base_cmd + ["-coverprofile", os.path.join(coverdir, get_coverprofile_filename(pkg, buildtags)), pkg]
+        print(" ".join(cmd))
         app = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
         for line in app.stdout:
             # we are trying to generate coverage reports for everything in the base package, and some may not be