manually add dependency on go-getter

vendor/github.com/mitchellh/go-testing-interface/testing_test.go

@@ -0,0 +1,15 @@
+package testing
+
+import (
+	"testing"
+)
+
+func TestT(t *testing.T) {
+	testTFunc(t) // Just verify this doesn't give a compiler error
+}
+
+func TestRuntimeT(t *testing.T) {
+	var _ T = new(RuntimeT) // Another compiler check
+}
+
+func testTFunc(t T) {}