diff --git a/cmd/echoip/main_test.go b/cmd/echoip/main_test.go
new file mode 100644
index 0000000..045a82a
--- /dev/null
+++ b/cmd/echoip/main_test.go
@@ -0,0 +1,42 @@
+package main
+
+import "testing"
+
+func TestMultiValueFlagString(t *testing.T) {
+	var xmvf = []struct {
+		values multiValueFlag
+		expect string
+	}{
+		{
+			values: multiValueFlag{
+				"test",
+				"with multiples",
+				"flags",
+			},
+			expect: `test, with multiples, flags`,
+		},
+		{
+			values: multiValueFlag{
+				"test",
+			},
+			expect: `test`,
+		},
+		{
+			values: multiValueFlag{
+				"",
+			},
+			expect: ``,
+		},
+		{
+			values: nil,
+			expect: ``,
+		},
+	}
+
+	for _, mvf := range xmvf {
+		got := mvf.values.String()
+		if got != mvf.expect {
+			t.Errorf("\nFor: %#v\nExpected: %v\nGot: %v", mvf.values, mvf.expect, got)
+		}
+	}
+}