add github.com/docker/docker dependency

vendor/github.com/docker/distribution/health/checks/checks_test.go

@@ -0,0 +1,25 @@
+package checks
+
+import (
+	"testing"
+)
+
+func TestFileChecker(t *testing.T) {
+	if err := FileChecker("/tmp").Check(); err == nil {
+		t.Errorf("/tmp was expected as exists")
+	}
+
+	if err := FileChecker("NoSuchFileFromMoon").Check(); err != nil {
+		t.Errorf("NoSuchFileFromMoon was expected as not exists, error:%v", err)
+	}
+}
+
+func TestHTTPChecker(t *testing.T) {
+	if err := HTTPChecker("https://www.google.cybertron", 200, 0, nil).Check(); err == nil {
+		t.Errorf("Google on Cybertron was expected as not exists")
+	}
+
+	if err := HTTPChecker("https://www.google.pt", 200, 0, nil).Check(); err != nil {
+		t.Errorf("Google at Portugal was expected as exists, error:%v", err)
+	}
+}