Fix #109, #116, #131: don't report in deadcode about unused test functions in main package

Author: jirfag

Gopkg.lock

@@ -0,0 +1,15 @@
+package main
+
+import "testing"
+
+func TestF(t *testing.T) {
+
+}
+
+func BenchmarkF(t *testing.B) {
+
+}
+
+func ExampleF() {
+
+}