verify_works.go

// you must provide the account hex, signature hex and the message wrapped with <Bytes>...</Bytes>

// To get the hex from the account you can do:
// import { u8aToHex, u8aToU8a } from "@polkadot/util";
// const hexPublicKey = u8aToHex(decodeAddress(account.address));

func TestVerifySR25519(t *testing.T) {
	const pubhex = "0xf84d048da2ddae2d9d8fd6763f469566e8817a26114f39408de15547f6d47805" 
	const sighex = "0x48ce2c90e08651adfc8ecef84e916f6d1bb51ebebd16150ee12df247841a5437951ea0f9d632ca165e6ab391532e75e701be6a1caa88c8a6bcca3511f55b4183"
	const challenge = "<Bytes>message to sign</Bytes>"
	verifySR25519(
		t,
		pubhex,
		sighex,
		challenge,
	)
}

func verifySR25519(t *testing.T, address, signature, challenge string) {
	// decodes the public hex to a schnorrkel.PublicKey
	pub, err := schnorrkel.NewPublicKeyFromHex(address)
	require.NoError(t, err)

	// decodes the signature hex to a schnorrkel.Signature
	sig, err := schnorrkel.NewSignatureFromHex(signature)
	require.NoError(t, err)

	// this is the ctx the polkadot-js uses to create the signature
	ctx := []byte("substrate")

	// creates the SigningContext using the wrapped message
	transcript := schnorrkel.NewSigningContext(ctx, []byte(challenge))

	// verify the signature using the public key and the signing context
	ok, err := pub.Verify(sig, transcript)
	require.NoError(t, err)
	require.True(t, ok)
}