diff --git a/transport/internet/tls/pin_test.go b/transport/internet/tls/pin_test.go
new file mode 100644
index 000000000..9607fe1f7
--- /dev/null
+++ b/transport/internet/tls/pin_test.go
@@ -0,0 +1,110 @@
+package tls
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCalculateCertHash(t *testing.T) {
+	/* This is used to make sure that the hash signature generated is consistent
+	   Do NOT change this test to suit your modification.
+	*/
+	const CertBundle = `
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+	t.Run("bundle", func(t *testing.T) {
+		hash := CalculatePEMCertChainSHA256Hash([]byte(CertBundle))
+		assert.Equal(t, "WF65fBkgltadMnXryOMZ6TEYeV4d5Q0uu4SGXGZ0RjI=", hash)
+	})
+	const Single = `-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
+`
+	t.Run("single", func(t *testing.T) {
+		hash := CalculatePEMCertChainSHA256Hash([]byte(Single))
+		assert.Equal(t, "FW3SVMCL6um2wVltOdgJ3DpI82aredw83YoCblkMkVM=", hash)
+	})
+}